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 malfunction indicator lamp (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 |
Did the DTC fail this ignition? | Go to Step 3 | Go to Intermittent Conditions |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 7 |
4 | Probe the ground circuit of the engine control module (ECM) with a test lamp connected to B+. Does the test lamp illuminate? | Go to Step 9 | Go to Step 8 |
5 | Test for shorted terminals and poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 |
6 | Replace the engine control module (ECM). Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- |
7 | Repair the an open or short to ground in the ignition 1 voltage circuit of the ECM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
8 | Repair an open or high resistance in the ground circuit of the ECM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
9 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 |
10 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK |
