P1607
P1607-PCM INTERNAL SHUTDOWN TIMER RATIONALITY TOO SLOW
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Powertrain Control Module (PCM) compares actual shutdown time to a calculated shutdown time value. The calculated shut down time value is based on the amount the Engine Coolant Temperature (ECT )should drop after a completely warmed up engine is shut down for a minimum of 8 hours. If the difference between actual shutdown time and the calculated shut down time is greater than a maximum value, a one trip failure will set. The shutdown time is measured again after 1 hour of ignition off time following the next engine warm up cycle. The PCM compares the shutdown time to a calculated value. If the difference is greater than a maximum value, the MIL is illuminated and a DTC will set.
- When Monitored:
With the engine running after a cycle when a complete engine warm up was achieved, the difference between engine coolant temperature and ambient air temperature less than or equal to 10° C (50° F) 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. Pre-Diagnostic Troubleshooting Procedure.
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.
1. Turn the ignition off.
2. Allow the engine to cool enough to allow the pressure in the coolant system to drop enough to safely remove the radiator cap.
3. 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. POWERTRAIN CONTROL MODULE (PCM)
1. Turn the ignition on.
2. With the scan tool monitor the Ignition Off Time value.
3. 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.
4. With the scan tool 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. Refer to the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.
No
- Replace and program the Powertrain Control Module. Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.