GM Service Manual Online
For 1990-2009 cars only

Object Number: 603430  Size: SF
Engine Controls Components
MIL Control and DLC
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The 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), DTC P0650 will set.

Conditions for Running the DTC

    • The engine is running.
    • 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 PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
    • The PCM stores the conditions present when the DTC set as Freeze Frame/Failure Records data.

Conditions for Clearing the MIL/DTC

    • The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

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.

Check for the following conditions:

    • Poor connections at the PCM or the instrument panel cluster (IPC) -- Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • A damaged harness -- Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM and Turn ON the ignition. Connect a voltmeter between the MIL control circuit and chassis ground. Observe the voltmeter while moving connectors and wiring harnesses related to the MIL. A change in voltage will indicate the location of the malfunction. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  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 3

Go to Step 5

3

With the scan tool, command the MIL OFF.

Is the MIL OFF?

--

Go to Diagnostic Aids

Go to Step 4

4

  1. Test the MIL control circuit for a short to ground. Refer to Circuit Testing 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 13

Go to Step 11

5

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector C1. Refer to Powertrain Control Module Replacement/Programming .
  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 6

Go to Step 7

6

  1. Test the MIL control circuit for a short to voltage. Refer to Circuit Testing 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 13

Go to Step 11

7

  1. Turn OFF the ignition.
  2. Reconnect the PCM connector.
  3. Disconnect the IPC connector.
  4. Connect the test lamp between the battery positive voltage and the MIL control circuit.
  5. With the scan tool, command the MIL ON and OFF.

Does the test lamp turn ON and OFF?

--

Go to Step 8

Go to Step 9

8

  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 13

Go to Step 12

9

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

Did you find and correct the condition?

--

Go to Step 13

Go to Step 10

10

  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 13

Go to Step 11

11

Important:: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 13

--

12

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

Is the action complete?

--

Go to Step 13

--

13

  1. Review and record scan tool Fail Records data.
  2. Clear DTCs.
  3. Operate the vehicle within the parameters listed in the conditions for running the DTC.
  4. With a scan tool, monitor Specific DTC info for DTC P0650 until the test runs.

Does the scan tool indicate DTC P0650 passed?

--

System OK

Go to Step 2