2007 Wrangler JK Factory Service Manual 9 - ENGINE

*START AND STALL CONDITION

For a complete wiring diagram Refer to Section 8W.



Possible Causes
  
CURRENT PCM DTCS
  
CURRENT SKIM DTCS
  
THROTTLE POSITION SENSOR SWEEP
  
TP SENSOR NO.1 VOLTAGE GREATER THAN 0.92 VOLTS WITH THROTTLE CLOSED
  
ECT SENSOR
  
OTHER POSSIBLE CAUSES FOR START AND STALL CONDITION
  
FUEL CONTAMINATION
  



Diagnostic Test

1. CHECKING DTCS

Ignition on, engine not running.
With a scan tool, select View DTCs.

Are any DTCs present?

Yes


No

2. CHECKING SKREEM DTCS

NOTE: If you are unable to communicate with the SKIM/SKREEM, refer to the VEHICLE THEFT AND SECURITY ELECTRICAL DIAGNOSTICS in Section 8 and perform the appropriate diagnostics.


With the scan tool, read the SKIM codes.

Are there any SKIM DTCs?

Yes


No

3. TP SENSOR SWEEP

Ignition on, engine not running.
With the scan tool read TP Sensor voltage.
While monitoring the scan tool, slowly open and close the Throttle on vehicles equipped with a manual throttle body.
On vehicles equipped with an electronic throttle body, use a scan tool to perform the pedal follower test and monitor both TP Sensor voltage readings.

Was the voltage change smooth?

Yes


No

4. TP SENSOR NO.1 VOLTAGE GREATER THAN 0.92 VOLTS WITH THROTTLE CLOSED

With the scan tool, read Throttle Position Sensor No.1 voltage.
Throttle must be against its stop.

Is the voltage 0.92 or less with the Throttle closed?

Yes


No

5. ECT SENSOR OPERATION

NOTE: For this test to be valid, the thermostat must be operating correctly.

NOTE: This test works best if performed on a cold engine (cold soaked).

NOTE: If the vehicle was allowed to sit over night with no engine start, coolant temperature should be near ambient temperatures.


Ignition on, engine not running.
With the scan tool, read the ECT value.

NOTE: If engine coolant temperature is above 82° C (180° F), allow the engine to cool until 65° C (150° F) is reached.


Start the engine.
During engine warm-up, monitor the Engine Coolant Temperature value. The temperature value change should be a smooth transition from start up to normal operating temp 82° C (180° F). The value should reach at least 82° C (180° F).

Did the Engine Temperature value increase smoothly and did it reach at least 82° C (180° F)?

Yes


No

6. OTHER POSSIBLE CAUSES OF START AND STALL CONDITION

The following additional items should be checked as a possible cause for a start and stall condition.
Refer to any Technical Service Bulletins (TSBs) that may apply to the symptom.
The exhaust system must be free of any restrictions.
The engine compression must be within specifications.
The engine valve timing must be within specifications.
The engine must be free from vacuum leaks.
The throttle body must be free of carbon buildup and dirt.

Do any of the above conditions exist?

Yes


No

7. FUEL PUMP DELIVERY

Verify that the Fuel tank is not empty before continuing.
Follow the diagnostics for Checking Fuel Delivery in this manual.

Was the No Start condition solved after following the above diagnostic test?

Yes


No