Circuit Description
The engine control module (ECM) is the control center of the fuel injector system. It constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the malfunction lamp indicator (MIL), and store a DTC or DTCs which identify the problem areas to aid the technician in making repairs. An electrically erasable programmable read only memory (EEPROM) is used to house the program information and the calibrations required for engine, transmission, and powertrain diagnostics operation. The ECM monitors EEPROM reset flag and lower power counter I/C overflow bits. If the ECM detects if lower power counter I/C has been reset due to battery disconnect or lower power counter I/C malfunction, the DTC will be stored.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1607 Control Module Ignition Off Timer Performance
Conditions for Running the DTC
The ignition is ON with the engine OFF.
Conditions for Setting the DTC
The ECM detects a low power counter error for more than 3 seconds.
Action Taken When the DTC Sets
| • | The MIL will illuminate. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |
2 |
Important: An intermittent ignition 1 voltage circuit and battery positive voltage circuit to the engine control module (ECM), may cause this DTC to set. Is the repair complete? | Go to Step 3 | -- |
3 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 4 |
4 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK |
