P0481

Cooling Fans And Relays:

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 (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 ODM B output 2, which controls the high speed and series/parallel cooling fan relays.

CONDITIONS FOR RUNNING THE DTC
The ignition is ON.

CONDITIONS FOR SETTING THE DTC
^ An improper voltage level has been detected on the fan 2 relay control circuit.
^ The above conditions present for at least 30 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (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 Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL 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 a scan tool.

DIAGNOSTIC AIDS
Check for the following conditions:
^ A faulty connection at PCM. Inspect the harness connectors for the following items:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- 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 fan 2 driver circuit and ground at the PCM harness connector while moving the connectors and the wiring harnesses related to the series/parallel fan relay and the high speed fan relay. A change in voltage will indicate the location of the fault.

Review the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.


TEST DESCRIPTION

Diagnostic Chart:

The numbers below refer to the step numbers on the diagnostic table.
1. The Powertrain On Board Diagnostic (OBD) System Check prompts you to complete some basic checks and store the freeze frame and failure records data on the scan tool.
2. Listen for an audible click when the relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests for voltage at the coil feed side of the relays.
4. Verifies that the PCM is providing ground to the relays.
5. Determines if ground is constantly being applied to the relays.
12. The PCM utilizes electrically Erasable Programmable Read-only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.