Circuit Description
The malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the driver that an emission system fault has occurred and that the engine control system requires service. The engine control module (ECM) monitors the MIL control circuit for conditions that are incorrect for the commanded state of the MIL. For example, a failure condition exists if the ECM detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON. If the ECM detects an improper circuit condition on the MIL control circuit, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0650 Malfunction Indicator Lamp (MIL) Control Circuit
Conditions for Running the DTC
| • | The engine speed is more than 80 RPM. |
| • | The ignition 1 voltage is between 10-18 volts. |
| • | The ECM has commanded the MIL ON and OFF at least once during the ignition cycle. |
| • | DTC P0650 runs continuously once the above conditions are met |
Conditions for Setting the DTC
| • | The ECM detects an open, a short to ground, or a short to voltage on the circuit that controls the MIL. |
| • | The condition exists for at least 4 seconds. |
Action Taken When the DTC Sets
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | Use the J 35616-A/BT-8637 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector. |
| • | The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to Engine Controls Component Views . |
| • | For an intermittent condition, refer to Intermittent Conditions . |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics or Instrument Cluster Schematics Connector End View Reference: Engine Control Module Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Is the MIL illuminated? | Go to Step 3 | Go to Step 5 |
3 | Command the MIL OFF with a scan tool. Is the MIL illuminated? | Go to Step 4 | Go to Diagnostic Aids |
4 |
Did you find and correct the condition? | Go to Step 16 | Go to Step 13 |
5 |
Is the MIL illuminated? | Go to Step 7 | Go to Step 6 |
6 | Does the fuse in the jumper wire open? | Go to Step 7 | Go to Step 8 |
7 |
Did you find and correct the condition? | Go to Step 16 | Go to Step 13 |
8 |
Does the test lamp illuminate? | Go to Step 10 | Go to Step 9 |
9 | Repair the open in the IPC ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 16 | -- |
10 |
Does the test lamp turn ON and OFF? | Go to Step 11 | Go to Step 12 |
11 | Test for an intermittent and for a poor connection at the IPC harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 15 |
12 |
Did you find and correct the condition? | Go to Step 16 | Go to Step 13 |
13 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 16 | Go to Step 14 |
14 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 16 | -- |
15 | Replace the IPC. Refer to Instrument Cluster Replacement . Did you complete the replacement? | Go to Step 16 | -- |
16 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 17 |
17 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |
