P0481

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 P0481 set indicates an improper voltage level has been detected on ODMs output 2, which controls the Cool Fan 2 and Cool Fan 3 relays.

Conditions for Setting the DTC

^ Ignition is on.
^ An improper voltage level has been detected on ODMs output 2 (the High Speed Fans Relay driver circuit).
^ Above conditions for at least 30 seconds.

Action Taken When the DTC Sets

^ The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ 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.

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 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 DMM connected to the High Speed Fans Control circuit at the PCM harness connector while moving connectors and wiring harnesses related to the Cool Fan 2 and Cool Fan 3 relay. A change in voltage will indicate the location of the fault.

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.

Test Description

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

2. Ensures battery voltage is present on the High Speed Fans Control circuit with the PCM disconnected.
3. Checks for a short to battery positive voltage on the High Speed Fans Control circuit.
4. Checks for shorted relay coil(s). A shorted relay coil will result in a current reading higher than 1.5 amps.
5. If the current reading from step 4 is not within the specified range, this step determines which relay coil is internally shorted.
17. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.