GM Service Manual Online
For 1990-2009 cars only

Mil Lamp


Object Number: 404392  Size: SF
OBD II Symbol Description Notice
Cell 21: Power, Ground, MIL and DLC
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

Output Driver Modules (ODMs) are used by the PCM to turn on many of the current-driven devices that are needed to control various engine and Transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding ON. Unlike the Quad Driver Modules (QDMs) used in prior model years, ODMs have the capability of diagnosing each output circuit individually. DTC P0650 set indicates an improper voltage level on the output circuit that controls the Malfunction Indicator Lamp (MIL).

Conditions for Setting the DTC

    • Ignition is ON.
    • An improper voltage level has been detected on ODM D output 1 (the MIL control circuit).
    • Above conditions for at least 30 seconds.

Action Taken When the DTC Sets

    • The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
    • The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

    • Poor connection at the PCM.
        Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
    • Damaged harness.
        Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a digital multimeter connected between the MIL control circuit and ground at the PCM harness connector while moving connectors and wiring harnesses related to the MIL. A change in voltage will indicate the location of the malfunction.

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

No Malfunction Indicator Lamp (MIL)

Number(s) below refer to the step number(s) on the Diagnostic Table:

  1. A no MIL condition accompanied by a no start condition suggests a faulty PCM ignition feed or battery feed circuit.

  2. Probe each of the PCM ground terminals to ensure that a good ground is present, using a test lamp connected to B+.

No Malfunction Indicator Lamp (MIL)

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Is DTC P0650 stored?

--

Go to Applicable DTC

Go to Step 3

3

Attempt to start the engine.

Does the engine start?

--

Go to Step 4

Go to Engine Cranks but Does Not Run

4

Check the PCM ignition feeds and battery feed fuses. Refer to Fuse Block Schematics .

Are the fuses OK?

--

Go to Step 5

Go to Step 9

5

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the PCM.
  3. Turn the ignition switch to the ON position.
  4. Probe the ignition feed circuit at the PCM harness connector with a test lamp J 35616-200 to ground.

Is the test lamp ON?

--

Go to Step 6

Go to Step 8

6

Probe the battery feed circuit at the PCM harness connector with a test lamp to ground.

Is the test lamp ON?

--

Go to Step 7

Go to Step 8

7

  1. Check for a faulty PCM ground or a poor PCM ground connection.
  2. If a problem is found, repair as necessary. Refer to Intermittents and Poor Connections Diagnosis .

Was a problem found?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--

8

Locate and repair open in PCM battery feed circuit or PCM ignition feed circuit as necessary. Refer to Wiring Repairs .

Is the action complete?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--

9

Locate and repair short to ground in PCM ignition feed circuit or PCM battery feed circuit as necessary. Refer to Wiring Repairs .

Is the action complete?

--

Go to Powertrain On Board Diagnostic (OBD) System Check

--