Diagnostic Test
- CHECKING DTCS
Ignition on, engine not running.
With a scan tool, read DTCs.
Are any DTCs present?
- Yes : Refer to the appropriate Diagnostic Procedure.
- No : Go To 2
- CHECKING SKIM DTCS NOTE: If you are unable to communicate with the SKIM/SKREEM, refer to the VEHICLE THEFT SECURITY - ELECTRICAL DIAGNOSTICS and perform the appropriate diagnostics.
With the scan tool, read the SKIM codes.
Are there any SKIM DTCs?
- Yes : Refer to VEHICLE THEFT SECURITY - ELECTRICAL DIAGNOSTICS .
- No : Go To 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 3.7L or 4.7L engine.
On vehicles equipped with a 5.7L engine, using a scan tool perform the pedal follower test and monitor both TP Sensor voltage readings.
Was the voltage change smooth?
- Yes : Go To 4
- No : Replace the Throttle Position Sensor on a 3.7L and 4.7L engines or the Throttle Body Assembly on a 5.7L engine.
- 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 : Go To 5
- No : Check for a binding throttle condition. If OK, replace the Throttle Position Sensor or the Throttle Body Assembly on a 5.7L
- 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 : Go To 6
- No : Replace the Engine Coolant Temperature Sensor.
- 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 : Repair as necessary.
- No : Go To 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 : Test Complete.
- No : Check for contamination/water in the fuel. Ensure the fuel being used in this vehicle meets manufactures Fuel Requirement, refer to the owner's manual.