Circuit Description
The malfunction indicator lamp (MIL) is located on the instrument panel cluster. The MIL will illuminate when there is an emission related failure or the ignition is ON with the engine OFF. Ignition 1 voltage is supplied to the MIL. The engine control module (ECM) turns the MIL ON by grounding the control circuit of the MIL using a low side driver. The ECM monitors the voltage level on the control circuit of the MIL. If the ECM detects a short to voltage on the control circuit of the MIL, DTC P1650 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1650 Malfunction Indicator Lamp (MIL) Control Circuit High Voltage
Conditions for Running the DTC
| • | The ignition is ON or the engine is operating. |
| • | The ignition 1 voltage is more than 10 volts. |
| • | DTC P1650 runs continuously once the above condition is met. |
Conditions for Setting the DTC
The ECM detects a short to voltage on the control circuit of the MIL for 24 seconds.
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the 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 non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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 - Engine Controls? | -- | Go to Step 2 | |
2 |
Does DTC P1650 set? | -- | Go to Step 4 | Go to Step 3 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions |
Does the MIL illuminate? | -- | Go to Step 5 | Go to Step 6 | |
5 | Test for shorted terminals and poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 7 |
6 | Repair a short to voltage on the control circuit of the MIL. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 8 | -- |
7 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- |
8 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 9 |
9 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
