GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 DeVille 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 DTC P0650

Circuit Description

The powertrain control module (PCM) uses output driver modules (ODMs) to control many functions of the engine, and the transaxle. The ODMs supply the ground path for the PCM controlled device when the PCM commands the device ON. Each ODM is able to control several outputs. Unlike the quad driver modules (QDMs) used in earlier model years, the ODMs are able to diagnose each output circuit. The PCM monitors the ODMs for circuit conditions that are incorrect for the commanded state of the ODM. If the PCM detects an improper circuit condition in the ODM that controls the malfunction indicator lamp (MIL), the DTC P0650 will set.

Conditions for Running the DTC
    • The engine is running.
    • The system voltage is between 8-16 volts.

Conditions for Setting the DTC
    • The PCM detects an improper voltage level on the output circuit that controls the MIL.
    • The condition exists for at least 10 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.

Diagnostic Aids

To determine whether an improper voltage level exists on the output circuit, the PCM compares the voltage level to the commanded state. For example, a failure condition exists if the PCM detects a low voltage level when the device is commanded OFF, or a high voltage level when the device is commanded ON.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Is DTC P1634 also set?

Go to DTC P1634

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the malfunction indicator lamp (MIL) display on the instrument panel cluster (IPC).

Is the MIL ON?

Go to Step 4

Go to Step 6

4

Command the MIL OFF with a scan tool.

Is the MIL OFF?

Go to Intermittent Conditions

Go to Step 5

5

  1. Test the MIL control circuit for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.
  2. If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

6
  1. Turn OFF the ignition.
  2. Disconnect the PCM connector. Refer to Powertrain Control Module Replacement .
  3. Connect the test lamp between the MIL control circuit and ground.
  4. Turn ON the ignition, with the engine OFF.

Is the test lamp ON?

Go to Step 7

Go to Step 8

7
  1. Test the MIL control circuit for a short to voltage. Refer to Testing for a Short to Voltage in Wiring Systems.
  2. If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 11

8
  1. Turn OFF the ignition.
  2. Connect the PCM connector.
  3. Disconnect the IPC connector.
  4. Connect the test lamp between the battery positive voltage and the MIL control circuit.
  5. Use the scan tool in order to command the MIL ON and OFF.

Does the test lamp turn ON and OFF?

Go to Step 9

Go to Step 10

9
  1. Inspect for poor connections at the IPC harness connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

10
  1. Test for an open MIL control circuit. Refer to Testing for Continuity in Wiring Systems.
  2. If a condition is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 11

11
  1. Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If a condition is found, repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

12

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 14

--

13

Replace the IP cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 14

--

14
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC run and pass?

Go to Step 15

Go to Step 2

15

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK