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. For example, a failure condition exists if the control module detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON. 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 speed is more than 400 RPM. |
| • | The ignition voltage is between 6-18 volts. |
| • | DTC P0650 runs continuously when the above conditions are met. |
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 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
| • | 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 powertrain control module (PCM) 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 no voltage on the MIL control circuit.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics , Engine Controls Schematics , or Power Distribution Schematics Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views or Powertrain Control Module Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 | Command the malfunction indicator lamp (MIL) ON and OFF with a scan tool. Does the MIL turn ON and OFF when commanded with a scan tool? | -- | Go to Step 3 | Go to Step 4 |
3 |
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions |
4 | Is the MIL always ON? | -- | Go to Step 6 | Go to Step 5 |
5 | Inspect the fuse that supplies battery voltage to the MIL. Is the fuse open? | -- | Go to Step 13 | Go to Step 7 |
Is the MIL OFF? | -- | Go to Step 12 | Go to Step 14 | |
Is the voltage less than the specified value? | 0.3 V | Go to Step 8 | Go to Step 15 | |
8 |
Is the MIL illuminated? | -- | Go to Step 12 | Go to Step 9 |
9 |
Does the test lamp illuminate for all circuits? | -- | Go to Step 10 | Go to Step 16 |
10 | Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct a condition? | -- | Go to Step 19 | Go to Step 11 |
11 | Test for an intermittent and for a poor connection at the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 17 |
12 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 18 |
13 | Repair the short to ground in the ignition voltage circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | -- |
14 | Repair the short to ground in the MIL control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | -- |
15 | Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | -- |
16 | Repair the open in the ignition or battery positive voltage circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | -- |
17 | Replace the IPC. Refer to Instrument Cluster Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- |
18 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 19 | -- |
19 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 20 |
20 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
