2014 Jeep Wrangler JK Factory Service Manual 29 - Non-DTC Diagnostics

Drivability - Diesel

ENGINE WILL NOT CRANK

For a complete wiring diagram, refer to the Wiring Information.



Possible Causes

BATTERY CABLE HIGH RESISTANCE
BATTERY CABLES
TRANSMISSION IS NOT READING THE PROPER RANGE (AUTO) OR CLUTCH SWITCH IS NOT READING THE PROPER STATUS (MANUAL)
OPEN FUSED BATTERY (+) CIRCUIT
STARTER COIL DRIVER (INTERNAL TIPM)
SKREEM CODES PRESENT
STARTER MOTOR
STARTER RELAY
(T752) STARTER RELAY CONTROL CIRCUIT OPEN
(T752) STARTER RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE
(T750) STARTER RELAY OUTPUT CIRCUIT OPEN
MECHANICAL PROBLEM
POWERTRAIN CONTROL MODULE

1. BATTERY CABLES



NOTE: The battery must be fully charged before diagnosing a no crank condition.
1. Turn the ignition off.
2. Inspect the battery cables for corrosion, looseness or other problems.


Is there evidence of problems?

Yes


No


2. CHECK THE BATTERY CABLES FOR HIGH RESISTANCE

1. Using the service information, check the battery cables for high resistance.


Did either battery cable have a voltage drop greater than 0.2 Volt?

Yes


No


3. TIPM CAN BUS CODES PRESENT

1. With the scan tool, read the TIPM DTCs.


NOTE: If there are CAN BUS related problems the TIPM will not supply power to the Starter Relay coil.


Does the scan tool display any CAN Bus related DTCs in the TIPM?

Yes


No


4. CHECK THE TRANSMISSION OR CLUTCH STATUS



NOTE: If there are DTCs related to the Clutch switch or Neutral Safety Switch, perform the diagnostic procedure for those DTCs before continuing.
1. With the scan tool, read the status of the Transmission range (Auto) or Clutch Switch position (Manual).

NOTE: The Auto Transmission must be in Park/Neutral position and the Manual Transmission Clutch Switch must read Clutch depressed in order for the engine to crank.


Does the scan tool display as described above?

Yes


No


5. CHECKING STARTER OPERATION
1. Turn the ignition off.
2. Remove the Starter Relay from the TIPM.

WARNING:

THE TRANSMISSION MUST BE IN NEUTRAL AND THE PARK BRAKE MUST BE SET FOR THIS TEST.

WARNING:

THE ENGINE MAY CRANK IN THE NEXT STEP. WHEN THE ENGINE IS CRANKING, DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.

3. Momentarily jumper Starter Relay connector cavities 30 and 87 in the TIPM connector.


Did the engine crank?

Yes


No


6. STARTER RELAY

1. Install a known good relay in place of the Starter Relay.
2. Attempt to start the engine.


Does the engine crank?

Yes


No


7. CHECK THE PCM POWERS AND GROUNDS

1. (Refer to 29 - Non-DTC Diagnostics/Drivability - Diesel - Diagnosis and Testing) and perform the Checking the PCM POWER AND GROUND diagnostic procedure.


Were any problem found with the PCM powers and grounds?

Yes


No


8. CHECK THE STARTER COIL DRIVE CIRCUIT (INTERNAL TIPM)
1. Turn the ignition off.
2. Remove the Starter Relay from the TIPM.
3. Using a 12-Volt test light connected to ground, check the Starter Coil Driver circuit in the Starter Relay connector while turning the ignition switch to the START position.


Does the test light illuminate with the ignition switch in the START position?

Yes


No


9. CHECK THE (T752) STARTER RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the PCM harness connectors.
3. Remove the ASD Relay from the TIPM.
4. Using a jumper wire, connect ASD Relay connector cavities 30 and 87 in the TIPM.
5. Turn the ignition on.
6. Measure the voltage of the (T752) Starter Relay Control circuit.


Is the voltage above 1.0 volt?

Yes


No


10. CHECK THE (T752) STARTER RELAY CONTROL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Remove the jumper wire and install the ASD Relay.
3. Measure the resistance of the (T752) Starter Relay Control circuit between the PCM harness connector and the Starter Relay connector in the TIPM.


Is the resistance below 5.0 ohms?

Yes


No


11. CHECK THE FUSED B(+) CIRCUIT FOR AN OPEN
1. Using a 12-Volt test light connected to ground, check the Fused B(+) circuit in the Starter Relay connector in the TIPM.


Is the test light illuminated and bright?

Yes


No


12. CHECK THE (T750) STARTER RELAY OUTPUT CIRCUIT FOR AN OPEN
1. Disconnect the (T750) Starter Relay Output wire from the Starter Solenoid.
2. Connect the (T750) Starter Relay Output wire (at the Starter) to ground.
3. Using a 12-Volt test light connected to 12-Volts, check the (T750) Starter Relay Output circuit at the Starter Relay connector in the TIPM.


Does the test light illuminate brightly?

Yes


No


13. MECHANICAL PROBLEM

1. Turn the ignition off.
2. Attempt to manually rotate the crankshaft 360°.


Is the crankshaft able to rotate 360°?

Yes


No

ENGINE CRANKS BUT WILL NOT START

For a complete wiring diagram, refer to the Wiring Information.



Possible Causes

SKREEM CODES PRESENT
INTAKE SYSTEM RESTRICTION
ECT SENSOR
FUEL INJECTOR LOW-SIDE CONTROL CIRCUIT SHORTED TO VOLTAGE
FUEL SUPPLY CONTAMINATION
FUEL DELIVERY SYSTEM FAILURE
GLOW PLUGS
ENGINE DRIVE BELT
POWERTRAIN CONTROL MODULE

1. PCM CODES PRESENT



NOTE: The PCM must have proper power and ground connections for the following tests to be valid. Refer to Checking the PCM Power and Grounds in the symptom list.
1. Turn the ignition on.
2. With the scan tool, read the PCM DTCs.


Does the scan tool display any PCM DTCs?

Yes


No


2. SKREEM CODES PRESENT

1. With the scan tool, read the SKREEM DTCs.


Does the scan tool display any SKREEM DTCs?

Yes


No


3. CHECK FOR INTAKE SYSTEM RESTRICTIONS

1. Turn the ignition off.
2. Make sure vehicle has adequate fuel supply in fuel tank.
3. Inspect all air intake and turbocharger related hoses/tubes and connections.
4. Inspect the air filter for excessive dirt, soiling or other problems that may cause restricted air flow.


Were any problems found?

Yes


No


4. ECT SENSOR

1. Using a temperature probe, check the vehicle temperature near the ECT Sensor.
2. Turn the ignition on.
3. With the scan tool in Sensors, read the ECT Sensor temperature.
4. Compare the temperature probe reading with the scan tool reading.


Are the two readings within 10°C of each other?

Yes


No


5. GLOW PLUGS



NOTE: Prior to performing this test, be sure to check the Glow Plug operation.
1. Refer to the service information and check the Glow Plugs for proper operation.


Are the Glow Plugs operating properly?

Yes


No


6. CHECK THE FUEL DELIVERY SYSTEM

1. Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. (Refer to 29 - Non-DTC Diagnostics/Drivability - Diesel - Diagnosis and Testing) .


Is there any evidence of problems?

Yes


No


7. FUEL INJECTOR LOW-SIDE CONTROL CIRCUIT(S) SHORTED TO VOLTAGE

1. Turn the ignition off.
2. Disconnect the each Fuel Injector harness connector.
3. Disconnect the PCM harness connectors.
4. Remove the ASD Relay from the TIPM.
5. Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.
6. Turn the ignition on.
7. Measure the voltage of each Fuel Injector Low-Side Control circuit in the Fuel Injector harness connectors.


Is there any voltage present?

Yes


No


8. ENGINE DRIVE BELT

1. Refer to the service information to ensure the Engine Drive Belt is installed correctly and the camshaft and crankshaft gears are timed correctly.


Were any problems found?

Yes


No

LACK OF ENGINE POWER

Special Tools: Click to display a list of tools used in this procedure

For a complete wiring diagram, refer to the Wiring Information.



Possible Causes

AIR IN FUEL SYSTEM
INJECTOR QUANTITY ADJUSTMENT
INTAKE/EXHAUST SYSTEM RESTRICTION
EGR SYSTEM PROBLEM
LOW ENGINE COMPRESSION
INTAKE AIR SYSTEM LEAK
FUEL DELIVERY SYSTEM FAILURE
ENGINE DRIVE BELT/CHAIN
FUEL INJECTOR(S)
FUEL SYSTEM CONTAMINATION
TURBOCHARGER

1. CHECKING FOR PCM DTCS

WARNING:

High Pressure fuel lines deliver diesel fuel under extreme pressure from the injection pump to the fuel injectors. This may be as high as 23,200 PSI (1600BAR). Use extreme caution when inspecting for high pressure fuel leaks. Failure to follow these instructions may result in possible serious or fatal injury.

WARNING:

Fuel under this amount of pressure can penetrate skin causing possible serious or fatal injury. Inspect for high pressure fuel leaks with a sheet of cardboard. Wear safety goggles and adequate protective clothing when servicing fuel system. Failure to follow these instructions may result in possible serious or fatal injury.

1. Turn the ignition on.
2. With the scan tool, read the PCM DTCs.


Are there any DTCs present?

Yes


No


2. CHECKING BOOST PRESSURE

1. Turn the ignition on.


NOTE: This test requires two people. One person to test drive the vehicle while a technician observes the scan tool readings.
2. With the scan tool in Sensors, read and compare the Boost Pressure (PSI) with the Boost Pressure Desired/Setpoint (PSI) while test driving the vehicle under various load conditions such as idle, hard acceleration, and cruise.

NOTE: The Boost Pressure reading should directionally follow (trail) the Boost Pressure Desired/Setpoint reading.


Does the Boost Pressure reading follow the Boost Pressure Desired/Setpoint reading?

Yes


No


3. INJECTOR QUANTITY ADJUSTMENT



NOTE: Each Fuel Injector is labeled with a code. This code determines the injector quantity adjustment. Each Injector code must be programmed into the PCM using the scan tool.
1. Turn the ignition off.
2. Use the service information to locate each fuel injector label and check for the correct code for each fuel injector in the PCM.


Are all of the injector codes correct?

Yes


No


4. CHECK THE FUEL DELIVERY SYSTEM

1. Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. (Refer to 29 - Non-DTC Diagnostics/Drivability - Diesel - Diagnosis and Testing) .


Is there any evidence of problems?

Yes


No


5. FUEL INJECTOR



NOTE: An injector that sticks open can cause this symptom. A sticking injector will cause the engine to misfire and emit excessive black smoke from the exhaust system.
1. Start and idle the engine.
2. With the scan tool, perform the Cylinder Fuel Quantity Correction Test.

NOTE: A problem injector will be indicated by a significant change in correction quantity as compared to the rest of the injectors.


Are any of the injectors displaying a significant amount of injection quantity correction?

Yes


No


6. ENGINE COMPRESSION

1. Start and idle the engine.
2. With the scan tool, perform the Cylinder Compression Test.


Does the Cylinder Compression Test indicate low compression in any of the cylinders?

Yes


No


7. ENGINE DRIVE BELT/CHAIN

1. Refer to the Service Information to ensure the Engine Drive Belt/Chain is installed correctly and the camshaft and crankshaft gears are timed correctly.


Were any problems found?

Yes


No


8. CHECK FOR INTAKE AND EXHAUST SYSTEM RESTRICTIONS

1. Turn the ignition off.
2. Inspect the exhaust system for damaged components that could cause exhaust flow blockage.
3. Inspect all air intake, crankcase vent and turbocharger related hoses/tubes and connections for damage, air leaks or blockage.
4. Inspect the Charge Air Cooler hoses/tubes and connections.
5. Inspect the air filter for excessive dirt, soiling or other problems that may cause restricted air flow.


Were any problems found?

Yes


No


9. CHECKING INTAKE SYSTEM LEAKS



NOTE: Inspect all air intake and turbocharger related tubes for damage, restriction or poor connection. Any of these conditions can cause a poor performance/lack of power symptom.
1. Turn the ignition off.
2. Remove the Crankcase Vent Heater.
3. Remove the Mass Air Flow Sensor from the Turbocharger inlet tube.
4. Seal off and/or plug the turbocharger inlet tube where the MAF sensor was removed.
5. Connect the Kit, EELD And Accessory 8404C Evaporative Emissions Leak Detector (EELD) to the Crankcase Vent Heater port in the intake duct and begin injecting smoke into the intake system.
6. Observe all intake system components for evidence of smoke leakage.


Is there evidence of smoke leakage?

Yes


No

CHECKING THE ENGINE MECHANICAL SYSTEMS

For a complete wiring diagram, refer to the Wiring Information.



Possible Causes

CHECKING ENGINE MECHANICAL SYSTEMS

CHECKING ENGINE MECHANICAL

WARNING:

Do not attempt to remove or separate high pressure fuel line. Attempting to do so could result in possible serious or fatal injury.



NOTE: The following items should be checked as a possible cause of a Driveability or No-Start problem:

  • Engine Valve Timing - must be within specification.
  • Engine Compression - must be within specifications.
  • Camshaft Lobes - check for abnormal wear.
  • Camshaft Position Sensor - check the camshaft position sensor tooth for debris and deterioration.
  • Crankshaft Position Sensor - check the crankshaft magnetic strip for debris and deterioration.
  • Engine Exhaust System - must be free of any restriction.
  • Engine Drive Belt and Sprockets - must be properly positioned.
  • Vacuum System - must operate properly and be free of any vacuum leaks.
  • Fuel - must have adequate supply and must be free of contamination (ie. debris, water and gasoline).
  • Fuel Injectors - must not be plugged or restricted.
  • Fuel Lift Pump - must operate properly (where applicable).
  • Fuel Injection Pump - must be producing the correct output volume and pressure.
  • Inspect the Fuel Lines, Fuel Filter and Fuel Pressure Relief Valve for signs of restriction and leaks.

NOTE: Check for any Technical Service Bulletins that may relate to the problem.


Are there any problems evident?

Yes


No

CHECKING THE PCM POWER AND GROUND CIRCUITS


Possible Causes

FUSED ASD RELAY BATTERY SUPPLY CIRCUIT OPEN
(K51) ASD RELAY CONTROL CIRCUIT OPEN/HIGH RESISTANCE
(F342) ASD RELAY OUTPUT CIRCUIT OPEN/HIGH RESISTANCE
(F344) ASD RELAY OUTPUT CIRCUIT OPEN/HIGH RESISTANCE
(Z905) PCM GROUND CIRCUIT OPEN/HIGH RESISTANCE
(F202) FUSED IGNITION SWITCH (START/RUN) OUTPUT CIRCUIT OPEN/HIGH RESISTANCE
ASD RELAY
POWERTRAIN CONTROL MODULE (PCM)

1. CHECK THE PCM GROUND CIRCUITS FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Using a 12-Volt test light connected to 12-Volts, check the (Z905) PCM Ground circuits at the PCM C2 harness connector.


Is the test light illuminated and bright for each cavity?

Yes


No


2. CHECK THE (F202) FUSED IGNITION SWITCH START/RUN OUTPUT CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition to the Start position.
2. Using a 12-Volt test light connected to ground, check the (F202) Fused Ignition Switch Start/Run Output circuit at PCM C2 harness connector.
3. Turn the ignition to the Run position.
4. Using a 12-Volt test light connected to ground, check the (F202) Fused Ignition Switch Start/Run Output circuit in PCM C2 harness connector.


Is the test light illuminated and bright for both ignition switch positions?

Yes


No


3. CHECKING THE ASD RELAY SYSTEM
1. Turn the ignition off.
2. Connect a jumper wire between ground and the (K51) ASD Relay Control circuit at PCM C2 harness connector.
3. Turn the ignition on.
4. Using a 12-Volt test light connected to ground, check the (F342) Fused ASD Relay Output circuit and the (F344) Fused ASD Relay Output circuit at the PCM C2 harness connector.


Is the test light illuminated and bright at each cavity?

Yes


No


4. CHECK THE FUSED ASD RELAY BATTERY SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Remove the ASD Relay from the TIPM.
3. Using a 12-Volt test light connected to ground, check both Fused ASD Relay Battery Supply circuits in ASD Relay connector.


Is the test light illuminated and bright?

Yes


No


5. CHECK THE (K51) ASD RELAY CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Measure the resistance of the (K51) ASD Relay Control circuit between the ASD Relay connector and the PCM C2 harness connector.


Is the resistance below 5.0 Ohms?

Yes


No


6. CHECK THE (F344) ASD RELAY OUTPUT CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Connect a jumper wire between cavity 30 and cavity 87 in the ASD Relay connector.
2. Using a 12-Volt test light connected to ground, check the (F342) Fused ASD Relay Output circuit and the (F344) Fused ASD Relay Output circuit at the PCM C2 harness connector.


Is the test light illuminated and bright at each cavity?

Yes


No


7. ASD RELAY

1. Turn the ignition off.
2. Reinstall the ASD Relay.
3. Reconnect the PCM C2 harness connector.
4. Turn the ignition on.
5. Backprobe the (K51) ASD Relay Control circuit in PCM C2 harness connector. Using an Ohmmeter, measure the resistance between ground and the (K51) ASD Relay Control circuit.


Is the resistance below 5.0 Ohms with the ignition on?

Yes


No

CHECKING THE FUEL DELIVERY SYSTEM

Special Tools: Click to display a list of tools used in this procedure



 

FUEL SYSTEM COMPONENTS

 

1. Fuel Lift Pump

4. Fuel Temperature Sensor

7. High Pressure Pump

2. Fuel Filter

5. Cascade Valve

8. Rail Pressure Sensor

3. Water in Fuel Sensor

6. Fuel Quantity Solenoid

9. Fuel Pressure Solenoid

For a complete wiring diagram, refer to the Wiring Information.



Possible Causes

AIR IN FUEL SYSTEM
FUEL QUALITY/CONTAMINATION
FUEL SYSTEM LEAK
FUEL LINE RESTRICTIONS
FUEL FILTER
FUEL LIFT PUMP
FUEL INJECTOR
FUEL PRESSURE SOLENOID
FUEL QUANTITY SOLENOID
HIGH PRESSURE DELIVERY PUMP

1. VISUAL INSPECTION



NOTE: If there are any DTCs present for the Fuel Pressure Solenoid, Fuel Quantity Solenoid, Fuel Injectors, or Fuel Pump Control Circuit or relay, repair those DTCs before continuing with the Fuel Delivery System test.

NOTE: For best results, perform Fuel Delivery System test with vehicle at room temperature. Extreme cold temperatures can cause inacurrate results.

NOTE: Make sure that the vehicle has at least 1/8 of a tank of fuel before proceding with this test.
1. Perform a visual inspection of the fuel system for any signs of a fuel leak.


Were any signs of a leak detected?

Yes


No


2. CHECKING SENSORS VALUES WITH THE SCAN TOOL

1. Turn the ignition on, engine not running.
2. With a scan tool, perform the following checks for a no start or hard start:

  • Check and compare the values of the Ambient Temperature Sensor, Coolant Temperature Sensor and Fuel Temperature Sensor with the key on. The values should read within 5°C (41°F) of each other.
  • Check and compare the values of the Air Inlet Pressure Sensor, Boost Pressure Sensor and Exhaust Differential Pressure Sensor. The sensors should read approximately the same.
  • Check the Crank/Cam synchronization during cranking.


Are the Cam and Crank sensors synchronized and the sensors reading normal?

Yes


No


3. SCAN TOOL TEST

1. Perform the following tests with the scan tool:

  • Compression Test. The RPM drop in each cylinder should be approximately equal.
  • Cylinder Balance Test. The RPM drop in each cylinder should be approximately equal.
  • Injector Kill Test. The RPM drop in each cylinder should be approximately equal.
  • Fuel Quantity Correction Test. Cylinder values should not exceed +4mm³.


Were any of the cylinders out of range as compared to the others during the scan tool tests?

Yes


No


4. CHECKING THE FUEL INJECTOR WIRING

1. Disconnect the Fuel Injector harness connector of the suspect injector.
2. Disconnect the Powertrain Control Module harness connector.
3. Using the wiring diagram as a guide, perform the following measurements:

  • Measure the resistance of the Fuel Injector High Side Control circuit between the Fuel Injector harness connector and the Powertrain Control Module harness connector.
  • Measure the resistance of the Fuel Injector Low Side Control circuit between the Fuel Injector harness connector and the Powertrain Control Module harness connector.


Is the resistance below 5.0 Ohms on both circuits?

Yes


No


5. CHECKING FUEL PRESSURE



NOTE: This test requires two people. One person to test drive the vehicle while a technician observes the scan tool readings. It may be easier to track both values by using the graph feature on the scan tool in data display.
1. With the scan tool, read and compare the Fuel Pressure reading with the Fuel Pressure Setpoint while cranking the engine on a no start, or while test driving the vehicle under various load conditions such as idle, hard acceleration, cruise and deceleration.

NOTE: The Fuel Pressure reading should closely follow the Fuel Pressure Setpoint reading. Fuel Pressure should stay within approximately 100 psi of the Fuel Pressure Setpoint at steady state/idle and 300 psi at load transitions.


Select the conclusion that best matches the result of the test:

The Fuel Pressure reading follows closely to the Fuel Pressure Setpoint reading.


The Fuel Pressure reading is too low.


The Fuel Pressure reading is excessive.


The Fuel Pressure reading is oscillating excessively above and below the Fuel Pressure Setpoint reading.


6. CHECKING FUEL PRESSURE SOLENOID MINIMUM PRESSURE

1. Turn the ignition off.
2. Disconnect the Fuel Pressure Solenoid.
3. Crank the engine for ten seconds.
4. With the scan tool, read the Fuel Pressure.


Select the conclusion that best matches the result of the test:

Fuel pressure reading is at or below 950 psi (65.5 bar)


Fuel pressure reading is still above 950 psi (65.5 bar)


7. CHECKING THE FUEL PRESSURE SOLENOID CIRCUITS

1. Disconnect the Fuel Pressure Solenoid harness connector.
2. Disconnect the Powertrain Control Module harness connector.
3. Using the wiring diagram as a guide, measure the resistance between ground and the Fuel Pressure Solenoid Control circuit.


Is the resistance below 10k Ohms?

Yes


No


8. CHECKING FUEL RETURN PRESSURE AT THE FUEL PRESSURE SOLENOID

1. Turn the ignition off for two minutes to make sure fuel pressure has purged from return system.
2. Connect a separate hose to the fuel return outlet port of the fuel rail.
3. Install the Decay Tool, Fuel 8978A in-line of return line.
4. Crank the engine or run the engine for ten seconds.


Is the fuel return pressure below 14.5 psi (1 bar)?

Yes


No


9. CHECKING FUEL RETURN VOLUME AT THE FUEL PRESSURE SOLENOID

1. Turn the ignition off for two minutes to make sure fuel pressure has purged from return system.
2. Open the valve to the reservoir.
3. Turn the ignition on for ten seconds.


Is the measured volume of fuel above 200 ml?

Yes


No


10. CHECKING FUEL RETURN PRESSURE FROM THE HIGH PRESSURE DELIVERY PUMP

1. Turn the ignition off.
2. Reconnect the Back Flow Return Line at the fuel return outlet port of the fuel rail.
3. Disconnect the Fuel Return Line coming from the High Pressure Delivery Pump at the Fuel Return Line junction/splice.
4. Install the Decay Tool, Fuel 8978A in-line between the Fuel Return Line and the splice.
5. Crank the engine or run the engine for ten seconds.


Is the fuel return pressure below 14.5 psi (1 bar)?

Yes


No


11. CHECKING FUEL RETURN VOLUME AT THE HIGH PRESSURE DELIVERY PUMP

1. Turn the ignition off for two minutes to make sure fuel pressure has purged from return system.
2. Disconnect the Decay Tool, Fuel 8978A .
3. Route the open end of the return line in a container (one liter capacity).
4. Turn the ignition on for ten seconds.


Is the measured volume of fuel above 200 ml?

Yes


No


12. CHECKING THE BACK FLOW RETURN LINE

1. Isolate for restriction in the Back flow Return Line by installing the Decay Tool, Fuel 8978A at different connecting points in the return line.


Were any restrictions found in the Back flow Return Line?

Yes


No


13. CHECKING THE FUEL RAIL PRESSURE SENSOR CIRCUITS

1. Disconnect the Fuel Rail Pressure Sensor harness connector.
2. Disconnect the Powertrain Control Module harness connector.
3. Using the wiring diagram as a guide, measure the resistance between the Fuel Rail Pressure Sensor harness connector and the Powertrain Control Module harness connector of the:

  • Fuel Rail Pressure Sensor 5-Volt Supply circuit.
  • Fuel Rail Pressure Sensor Signal circuit.
  • Fuel Rail Pressure Sensor Return circuit.


Is the resistance below 5 Ohms for each circuit?

Yes


No


14. CHECKING THE HIGH PRESSURE DELIVERY PUMP
1. Turn the ignition off.
2. Disconnect all four Fuel Injector harness connectors.
3. Using the DRBIII® as a lab scope:
4. Connect the positive lead to the signal circuit of the Rail Pressure Sensor by back probing the connector of the Rail Pressure Sensor. Be careful not to damage connector or terminals.
5. Connect the negative lead to a good engine or chassis ground.
6. Select PEP Module Tools on the DRBIII® screen.
7. Select Lab Scope.
8. Select Live Data.
9. Select 5-Volt Sensor.
10. Select Lab Scope with the F2 key.
11. Select Start with the F3 key.
12. Adjust the lab scope parameters as follows:

  • Time - 0.2 s/Div.
  • Voltage range - 2.0 Volts.
13. Crank the engine for 10 seconds and press hold.


NOTE: The High Pressure Delivery Pump uses three separate internal pistons to build high pressure in the fuel rail. The peaks on the lab scope correspond to the pressure spikes that occur when the pistons in the High Pressure Delivery Pump compress the fuel.
14. Compare the graph of the vehicle with the two sample graph's provided. Figure one is an example of a properly working High Pressure Delivery Pump. Figure two is an example of a High Pressure Delivery Pump with one faulty piston.


Are all three pistons operating properly in the High Pressure Delivery Pump?

Yes


No


15. CHECKING FUEL QUALITY/CONTAMINATION

1. Collect a fuel sample from the vehicle in a clean see through container.
2. Collect a fuel sample of fresh clean fuel in a clean see through container for reference.
3. Check the vehicle's fuel sample for the following:

  • Check the color of the fuel. Diesel fuel will generally be a yellow color.
  • Allow the fuel to settle and look for cloudiness indicating contamination.
  • Check the volatility of the fuel.
  • Look for a parting line in the fuel sample indicating another type of liquid mixed with the fuel.
  • Look for any signs of debris in the fuel sample.


Are there any signs of contamination or poor quality detected?

Yes


No


16. CHECKING THE FUEL LIFT PUMP OPERATION

1. Turn the ignition on.
2. With a scan tool, actuate the fuel pump control to ON (100%).


NOTE: It may be necessary to use a mechanics stethoscope in the next step.
3. Listen for the Fuel Lift Pump operation at the fuel tank.

CAUTION:

Stop all actuation tests before continuing.



Does the Fuel Lift Pump operate?

Yes


No


17. CHECKING THE LOW SIDE FUEL PRESSURE

1. Turn the ignition off.

WARNING:

The fuel system is under a constant pressure, even with the engine off. Before testing or servicing any fuel system, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

2. Disconnect the Fuel Filter Outlet fuel line at the Fuel Filter.
3. Install the Decay Tool, Fuel 8978A in'line between the Fuel Filter Outlet port and the fuel line.
4. Turn the ignition on.
5. Using the scan tool, actuate the Fuel Pump Relay Control to ON (100%). Observe the fuel pressure gauge.


NOTE: The fuel pressure should read between 50 psi (3.5 bar) and 65 psi (4.5 bar).

CAUTION:

Stop all actuation tests before continuing.



Select the conclusion that best matches the result of the test:

Fuel pressure is within the stated specification.


Fuel pressure is below the stated specification.


Fuel pressure is above the stated specification.


18. CHECKING THE FUEL PRESSURE BEFORE THE FUEL FILTER

1. Turn the ignition off.
2. Remove the Decay Tool, Fuel 8978A and reconnect the Fuel Filter Outlet line to the filter.
3. Disconnect the Fuel Filter Inlet line at the Fuel Filter.
4. Install the Decay Tool, Fuel 8978A in-line between the Fuel Filter Inlet and the fuel line.
5. Turn the ignition on.
6. Using the scan tool, actuate the fuel pump relay control to ON (100%). Observe the fuel pressure gauge.


NOTE: The fuel pressure should read between 50 psi (3.5 bar) and 65 psi (4.5 bar).

CAUTION:

Stop all actuation tests before continuing.



Is the fuel pressure reading within the stated specification?

Yes


No


19. CHECKING THE FUEL PUMP MAXIMUM OUTPUT AND PRESSURE RELIEF VALVE

1. Ignition on.
2. Using the scan tool, actuate the fuel pump relay control to ON (100%). Observe the fuel pressure gauge.
3. Close the valve after the gauge to allow maximum fuel pressure to build in the system.


NOTE: The fuel pressure should read between 90 psi (6.5 bar) and 116 psi (8.5 bar).

CAUTION:

Stop all actuation tests before continuing.



Is the fuel pressure within the stated specification?

Yes


No


20. FUEL SUPPLY VOLUME TEST AT FUEL FILTER OUTLET

1. Turn the ignition off.
2. Open the valve after the gauge.
3. Turn the ignition on.
4. Open the valve leading into the measuring container.
5. Using the scan tool, actuate the Fuel Pump Relay Control to ON (100%) for 10 seconds.
6. Measure the amount of fuel collected in the container.

CAUTION:

Stop all actuation tests before proceeding.



Is the measured volume of fuel above 450 ml?

Yes


No


21. CHECKING THE FUEL SUPPLY SYSTEM FOR AIR

1. Turn the ignition off.
2. Remove the Decay Tool, Fuel 8978A from the line.
3. Install a clear hose in-line as close to the High Pressure Pump inlet as possible.
4. Crank or star the engine and check for air bubbles in the clear tubing.


Were any air bubbles evident in the clear tubing?

Yes


No


22. CHECKING THE FUEL PRESSURE SOLENOID FOR LEAKAGE

1. Turn the ignition off.
2. Disconnect the Back Flow Return Line at the Fuel Pressure Solenoid.
3. Connect one end of a separate hose to the Fuel Rail Return Outlet Port and put the other end into a container.


NOTE: Keep in mind that the High Pressure Delivery Pump Fuel Return and the Fuel Pressure Solenoid Fuel return are both connected to the fuel return line. The fuel return line should either be capped or put into a container during the next step to catch any fuel spillage.
4. Crank the engine for 10 seconds and observe for any fuel coming from the Fuel Pressure Solenoid return.
5. With the Fuel Pressure reading less than the Fuel Pressure Setpoint reading, the Fuel Pressure Solenoid should be closed and little or no fuel should be present.


Is there any fuel present from the Fuel Pressure Solenoid during cranking?

Yes


No


23. CHECKING THE FUEL PRESSURE SOLENOID CIRCUITS

1. Disconnect the Fuel Pressure Solenoid harness connector.
2. Disconnect the Powertrain Control Module harness connector.
3. Using the wiring diagram as a guide, measure resistance between the Fuel Pressure Solenoid harness connector and the PCM harness connector of the:

  • Fuel Pressure Solenoid Control circuit.
  • Fuel Pressure Solenoid 12-Volt Supply circuit.


Is the resistance below 5.0 Ohms?

Yes


No


24. CHECKING THE HIGH PRESSURE DELIVERY PUMP
1. Turn the ignition off.
2. Reconnect the Back Flow Return Line at the Fuel Pressure Solenoid if disconnected.
3. Disconnect all four Fuel Injector harness connectors.
4. Using the DRBIII® as a lab scope:
5. Connect the positive lead to the signal circuit of the Rail Pressure Sensor by back probing the connector of the Rail Pressure Sensor. Be careful not to damage connector or terminals.
6. Connect the negative lead to a good engine or chassis ground.
7. Select PEP Module Tools on the DRBIII® screen.
8. Select Lab Scope.
9. Select Live Data.
10. Select 5-Volt Sensor.
11. Select Lab Scope with the F2 key.
12. Select Start with the F3 key.
13. Adjust the lab scope parameters as follows:

  • Time - 0.2 s/Div.
  • Voltage range - 2.0 Volts.
14. Crank the engine for 10 seconds and press hold.


NOTE: The High Pressure Delivery Pump uses three separate internal pistons to build high pressure in the fuel rail. The peaks on the lab scope correspond to the pressure spikes that occur when the pistons in the High Pressure Delivery Pump compress the fuel.
15. Compare the graph of the vehicle with the two sample graph's provided. Figure one is an example of a properly working High Pressure Delivery Pump. Figure two is an example of a High Pressure Delivery Pump with one faulty piston.


Are all three pistons operating properly in the High Pressure Delivery Pump?

Yes


No


25. FUEL QUANTITY SOLENOID

1. Turn the ignition off.
2. Disconnect the lab scope from the Rail Pressure Sensor.
3. Turn the ignition on.
4. Use a stethoscope the listen to the Fuel Quantity Solenoid.
5. Using the scan tool, actuate the Fuel Quantity Solenoid.
6. Use the table as a guide to check the operation of the Fuel Quantity Solenoid.
7. Compare the audible sound with the PWM actuation percentage from the chart.

FUEL QUANTITY SOLENOID ACTUATED

SOUND FROM FUEL QUANTITY SOLENOID
0% NO SOUND AUDIBLE
20% SOUND STEADY BUT HARDLY NOTICEABLE
40% SOUND STEADY AND NOTICEABLE
60% SOUND STEADY AND LOUD
80% SOUND STEADY BUT HARDLY NOTICEABLE
100% NO SOUND AUDIBLE


Select the conclusion that best matches the result of the test:

The Fuel Quantity Solenoid does not make any sound.


The Fuel Quantity Solenoid is audible but does not follow the table.


26. FUEL SUPPLY VOLUME TEST AT FUEL FILTER INLET

1. Turn the ignition off.
2. Remove the Decay Tool, Fuel 8978A from between the Fuel Filter Outlet and the fuel line.
3. Install the Decay Tool, Fuel 8978A between the Fuel Filter Inlet and the fuel line.
4. Empty the fuel in the container.
5. Turn the ignition on.
6. Using the scan tool, actuate the Fuel Pump Relay Control to ON (100%) for 10 seconds.
7. Measure the amount of fuel collected in the container.

CAUTION:

Stop all actuation tests before proceeding.



Is the measured volume of fuel above 450 ml?

Yes


No


27. CHECKING FOR A RESTRICTED EVAPORATIVE EMISSIONS SYSTEM

1. Turn the ignition off.
2. Remove the Fuel Cap.
3. Empty the fuel in the container.
4. Turn the ignition on.
5. Using the scan tool, actuate the Fuel Pump Relay Control to ON (100%) for 10 seconds.
6. Measure the amount of fuel collected in the container.

CAUTION:

Stop all actuation tests before proceeding.



Is the measured volume of fuel above 450 ml?

Yes


No


28. CHECKING THE FUEL PUMP CIRCUITS

1. Turn the ignition on.
2. Disconnect the Fuel Pump Module harness connector.
3. Connect a 12-volt test light between the Fuel Pump Control Output circuit and the Ground circuit at the Fuel Pump Module harness connector (body side).
4. With a scan tool, actuate the fuel pump control to ON (100%).


NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

CAUTION:

Stop all actuation tests before continuing.



Is the test light illuminated and bright?

Yes


No


29. FUEL PUMP OUTPUT CIRCUIT CHECK

1. Using a 12-volt test light connected to ground, check the Fuel Pump Output circuit at the Fuel Pump Module harness connector.
2. With a scan tool, actuate the fuel pump control to ON (100%).


NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.


Is the test light illuminated and bright?

Yes


No


30. FUEL PUMP GROUND CIRCUIT OPEN OR HIGH RESISTANCE

1. Turn the ignition off.
2. Using a 12-volt test light connected to 12 volts, check the Fuel Pump Motor Ground circuit at the Fuel Pump Module harness connector.


NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.


Is the test light illuminated and bright?

Yes


No