P1640

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DTC P1640 ODM Output Circuit Fault




Circuit Description
Output driver modules (ODMs) are used by the powertrain control module (PCM) to turn ON many of the current-driven devices that are needed to control various engine and transmission functions. Each 0DM is capable of controlling up to 11 separate outputs by applying ground to the device which the PCM is commanding ON.

ODMs have the capability of diagnosing each output circuit individually. DTC P1640 set indicates an improper voltage level has been detected on an 0DM output.

If the PCM detects an open circuit condition and a shorted to voltage circuit condition on the same circuit at the same time, then DTC P1640 will set. DTC P1640 is a type D code.

Conditions for Setting the DTC
- Ignition ON.
- Above conditions occur for at least 2.5 seconds.
- The PCM detects an open circuit condition and a shorted to voltage circuit condition on the same circuit at the same time.

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 was set as Failure Records only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the DTC
- A history DTC P1640 will clear after 40 consecutive warm-up cycles occur without a fault.
- DTC P1640 can be cleared by using the Scan Tool's "Clear Info" function.

Diagnostic Aids
Check for the following conditions:
- Poor connection at PCM - Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal4o-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 voltmeter connected to the MIL driver circuit at the PCM harness connector while moving connectors and wiring harnesses relates to the MIL. A change in voltage will indicate the location of the fault.
- Reviewing the Failure 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.