Circuit Description
The engine control module (ECM) is the control center of the fuel injection system. If 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 indicator lamp (MIL), and store a DTC or DTCs which identify the problem areas to aid the technician in making repairs. An electronically 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 DTC will be stored when the ECM detects SPI communication between main CPU and output driver I/C is corrupted.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1650 Control Module Internal Performance.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | Battery voltage is more than 11 volts. |
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 |
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 |
