P1607
P1607-PCM INTERNAL SHUTDOWN TIMER RATIONALITY
For a complete wiring diagram Consult Diagrams/Electrical.
Theory of Operation
When the engine is shut off the Engine Coolant temperature is measured. While the vehicle sets with the Ignition off, the ECT is expected to drop a specific amount depending on ambient air temperature, length of shutdown time, and other variables. If the temperature decrease is more than expected or less than expected, a one trip failure will occur after the first detected failure and the MIL will set after the second detected failure.
- When Monitored:
Ignition on and battery voltage greater than 10 volts.
- Set Condition:
This DTC sets if the engine coolant temp does not drop enough or drops too much during engine off time. This DTC may also set if the controller timer is inaccurate. Two Trip Fault. Three good trips to turn off the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview.
Diagnostic Test
1. ENGINE COOLANT INSPECTION
NOTE: This DTC will set if the engine cools quicker than is should compared to engine off times. If the customer washed a hot engine with the engine off, a One Trip Failure will set. If the vehicle is parked in a highly ventilated area or has a large fan blowing on it which might cause the engine to cool quicker than expected this DTC may set.
WARNING: Do not remove or loosen the radiator cap with the system hot and under pressure. Serious burns from coolant can occur.
Turn the ignition off.
Allow the engine to cool enough to allow the pressure in the coolant system to drop enough to safely remove the radiator cap.
Check the coolant level and condition.
Is the engine coolant level filled to the proper level?
Yes
- Go To 2
No
- Add the appropriate type and amount of engine coolant. Service and Repair
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
2. PCM
Turn the ignition on.
With the scan tool under PCM/NGC Data Display, locate the Ignition Off Time value.
While monitoring a stop watch, turn the Ignition off for 10 minutes, watch the stop watch for those 10 minutes, and then turn the Ignition on.
With the scan tool under Data Functions, check the Ignition Off Time value again.
Does the Ignition Time Off value on the scan tool match the actual time you had the Ignition off on the stop watch?
Yes
- The conditions that set the DTC are not active at this time. For further assistance Refer to the INTERMITTENT CONDITION Diagnostic Procedure.Intermittent Condition
No
- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.