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 control module monitors the MIL control circuit for conditions that are incorrect for the commanded state of the MIL. If the control module detects an improper voltage on the MIL control circuit, DTC P0650 will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0650 Malfunction Indicator Lamp (MIL) Control Circuit
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The control module detects that the commanded state of the MIL driver and the actual state of the control circuit do not match for more than 5 seconds.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | 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 3 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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for a short to ground in the MIL control circuit. With the engine control module (ECM) disconnected and the ignition ON, the MIL should be OFF.
-
This step tests for a short to voltage on the MIL control circuit. With the fuse removed, there should be less than 1 volt on the MIL control circuit.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Turn ON the ignition, with the engine OFF. Is the instrument cluster completely inoperative? | -- | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console | Go to Step 3 |
3 |
Does the MIL turn ON and OFF when commanded with a scan tool? | -- | Go to Step 4 | Go to Step 5 |
4 |
Does the DTC fail this ignition? | -- | Go to Step 6 | Go to Intermittent Conditions |
5 | Inspect the fuse that supplies voltage to the cluster. Is the fuse open? | -- | Go to Step 13 | Go to Step 6 |
Is the MIL OFF? | -- | Go to Step 7 | Go to Step 12 | |
Is the voltage less than the specified value? | 1 V | Go to Step 8 | Go to Step 14 | |
8 |
Is the MIL illuminated? | -- | Go to Step 11 | Go to Step 9 |
9 | Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 17 | Go to Step 10 |
10 | Test for an intermittent and for a poor connection at the IPC. 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 17 | Go to Step 15 |
11 | Test for an intermittent and for a poor connection at the 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 17 | Go to Step 16 |
12 | Test for a short to ground in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 |
13 | Test all circuits and components that use this voltage supply for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 |
14 | Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 17 | -- |
15 | Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement? | -- | Go to Step 17 | -- |
16 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 17 | -- |
17 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 18 |
18 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
