2012 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P0018-CRANKSHAFT/CAMSHAFT TIMING MISALIGNMENT - BANK 2 SENSOR 1

P0018-CRANKSHAFT/CAMSHAFT TIMING MISALIGNMENT - BANK 2 SENSOR 1

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





Theory of Operation

NOTE:

The CMP sensor is a dual read sensor reading both camshafts of it's correlating bank.


3.6L VVT Component Locations

CALLOUT

DESCRIPTION

1

VVT Actuator Bank 1 Position 2

2

VVT Actuator Bank 1 Position 1

3

VVT Actuator Bank 2 Position 1

4

VVT Actuator Bank 2 Position 2

5

Camshaft Position Sensor 2/1 Signal

6

Bank 2 Camshaft Sensor

7

Camshaft Position Sensor 2/2 Signal

8

Camshaft Position Sensor 1/2 Signal

9

Bank 1 Camshaft Sensor

10

Camshaft Position Sensor 1/1 Signal

The 3.6L engine has four separate Camshafts that the Powertrain Control Module (PCM) requires positional information from. There are two Camshaft Position (CMP) Sensors on the 3.6L, each CMP Sensor consists of four circuits. The sensors are located on the top end of each valve cover, closest to the transmission side of the engine. The CMP Sensor is an integrated circuit sensing device and on the end of each Camshaft is a magnetic encoder that is programmed with a magnetic pattern. The PCM provides a 5-Volt supply and a sensor ground circuit to the CMP Sensor and the CMP Sensor provides two Camshaft positional signals, the intake and exhaust camshaft position, to the PCM. The sensor detects the magnetically encoded information, a series of magnetic peaks and valleys, from the encoder. As each Camshaft rotates, the magnetic encoded pattern passes by the CMP Sensor creating a changing magnetic field at the sensor face. The changing magnetic field is interpreted by the sensor electronics and a digital output, ON/OFF or HIGH/LOW pattern, is produced. The length of the pulse widths generated by the CMP varies in size based on the velocity of the Camshaft. The PCM decodes the digital pattern to identify the Camshaft position. The information from each individual Camshaft along with the Crankshaft information is used to control and sequence the Variable Valve Timing (VVT) system and fuel injection events.



Possible Causes

ERRATIC CAM POSITION SENSOR SIGNAL
CAMSHAFT POSITION SENSOR TONE WHEEL/PULSE RING
ERRATIC CRANKSHAFT POSITION SENSOR SIGNAL
CRANKSHAFT POSITION SENSOR TONE WHEEL/PULSE RING
TIMING SPROCKET ALIGNMENT
CAMSHAFT POSITION SENSOR 2
CRANKSHAFT POSITION SENSOR

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


1. ACTIVE DTC

1. Turn the ignition on.
2. Using the scan tool, read DTCs.
3. Record the related Freeze Frame data.
4. Using the scan tool, erase DTCs.
5. Start the engine and allow it to reach operating temperature.

WARNING:

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

6. Using the scan tool, read the active DTCs.


NOTE: Diagnose and repair any Camshaft Position Actuator Circuit Open DTCs before continuing with this test.

NOTE: If the DTC does not reset it may be necessary to test drive the vehicle.


Is the DTC Active at this time?

Yes


No


2. CAMSHAFT POSITION SENSOR CIRCUIT WIRING OR CONNECTORS

1. Turn the ignition off.
2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Camshaft Position Sensor and the Powertrain Control Module (PCM).
3. Look for any chafed, pierced, pinched or partially broken wires.
4. Verify that there is good pin to terminal contact in the Camshaft Position Sensor and the Powertrain Control Module connectors.
5. Look for broken, bent, pushed out or corroded terminals.
6. Inspect the Camshaft Position Sensor for conditions such as loose mounting screws, damage or cracks.


Were any problems found?

Yes


No


3. CRANKSHAFT POSITION SENSOR CIRCUIT WIRING OR CONNECTORS

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Crankshaft Position Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Verify that there is good pin to terminal contact in the Crankshaft Position Sensor and the Powertrain Control Module connectors.
5. Remove the Crankshaft Position Sensor.
6. Inspect the Crankshaft Position Sensor, mounting area, and tone wheel for any condition that would result in an incorrect signal, such as damage, evidence of foreign material or excessive movement.


Were any problems found?

Yes


No


4. CAMSHAFT, TONE WHEEL OR PULSE RING

1. Turn the ignition off.
2. Remove the Camshaft Position Sensor.
3. Inspect the Camshaft Position Sensor, mounting area, and tone wheel for any condition that would result in an incorrect signal, such as damage, evidence of foreign material or excessive movement.


Were any problems found?

Yes


No


5. TIMING SPROCKET ALIGNMENT

1. Turn the ignition off.
2. Verify proper timing sprocket alignment in accordance with the Service Information.


Were any problems found?

Yes


No


6. CAMSHAFT POSITION SENSOR IRREGULAR SIGNAL

1. Turn the ignition off.
2. Install any previously removed components. Reconnect all connectors.
3. Using a lab scope and back probing tool, back probe the (K444) CMP Sensor Signal 2/1 circuit in the Camshaft Position Sensor harness connector.
4. Start the engine.
5. Wiggle the related wire harness and lightly tap on the Camshaft Position Sensor while monitoring the lab scope screen.
6. Monitor the Camshaft Position Sensor signal on the lab scope screen.


Were any Camshaft Position Sensor signals irregular or missing?

Yes


No


7. CRANKSHAFT POSITION SENSOR IRREGULAR SIGNAL

1. Turn the ignition off.
2. Using a lab scope and back probing tool, back probe the (K24) CKP Signal circuit in the Crankshaft Position Sensor harness connector.
3. Start the engine.
4. Wiggle the related wire harness and lightly tap on the Crankshaft Position Sensor while monitoring the lab scope screen.
5. Monitor the Crankshaft Position Sensor signal on the lab scope screen.


Were any Crankshaft Position Sensor signals irregular or missing?

Yes


No


8. CAMSHAFT POSITION SENSOR

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Camshaft Position Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Verify that there is good pin to terminal contact in the Camshaft Position Sensor and the Powertrain Control Module harness connectors.
4. Look for broken, bent, pushed out or corroded terminals.


Were any problems found?

Yes


No


9. CRANKSHAFT POSITION SENSOR

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Crankshaft Position Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Verify that there is good pin to terminal contact in the Crankshaft Position Sensor and the Powertrain Control Module harness connectors.
4. Look for broken, bent, pushed out or corroded terminals.


Were any problems found?

Yes


No


10. POWERTRAIN CONTROL MODULE (PCM)

1. Turn the ignition off.
2. Perform any Technical Service Bulletins that may apply.


Were there any TSBs related to this fault or condition?

Yes


No