GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The output driver module (ODM) is a control chip inside of the powertrain control module (PCM). The PCM contains multiple ODMs. ODMs provide grounded output control of devices. Each ODM output has an internal feedback circuit that connects to the PCM microprocessor. The PCM monitors voltage through the ignition 1 voltage circuit. Excessive voltage or current may cause damage to the PCM. If the ODM detects excessive current or voltage on an output control circuit, this DTC will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1640 Control Module Output A Circuit

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

    • ODM A has detected a voltage greater than 26.5 volts.
        OR
    • Excessive current is detected on any circuit to the ODM.
    • The above conditions are present for 30 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.

Diagnostic Aids

    • A condition with the charging system may cause this DTC to set. Refer to Charging System Test in Engine Electrical.
    • For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring System.

Step

Action

Yes

No

Schematic Reference: Starting and Charging Schematics in Engine Electrical or Engine Controls Schematics

Connector End View Reference: Engine Electrical Connector End Views in Engine Electrical, Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Is DTC P0560 set?

Go to DTC P0560 in Engine Electrical

Go to Step 3

3

Observe the Output Driver Data List with a scan tool.

Do any parameters indicate a fault present?

Go to Step 4

Go to Step 5

4

Test for a short to voltage on the control circuit of the component that indicated a fault. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Replace the powertrain control module (PCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 6

--

6

  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. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Does the DTC fail this ignition?

Go to Step 2

Go to Step 7

7

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

System OK