P1641

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 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 (ODMs) used in prior model years, ODMs have the capability of diagnosing each output circuit individually. A DTC P1641 set indicates an improper voltage level is detected on the output circuit which controls the A/C relay.

Conditions for Setting the DTC
^ The ignition is on.
^ An improper voltage level is detected on the output circuit which controls the A/C relay.
^ The above conditions are present for at least 30 seconds.

Action Taken When the DTC Sets
The PCM stores the conditions which were present when the DTC set as Fail Records data only.

Conditions for Clearing the MIL/DTC
^ A history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC may be cleared using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
Inspect for the following conditions:
^ A faulty connection at the PCM. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections.
^ 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 A/C compressor control relay control circuit and ground at the PCM harness connector while moving the connectors and the wiring harnesses related to the A/C compressor control relay. A change in the voltage indicates 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.