DTC Advanced Diagnostics: P0481 (3.0L Engine)
DTC P0481: RFC 2 System Malfunction
General Description
Radiator fan control (RFC) unit 2 controls the condenser fan speed based on the PWM control signal duty from the powertrain control module (PCM) to cool the condenser properly. The PCM monitors the condition of the RFC unit 2 control terminal voltage level and the current. If an abnormality of the terminal voltage level or an over current is detected, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 12 seconds or more |
| DTC Type | Two drive cycles, MIL off |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [Battery] | 10.0 V | 18.0 V |
| RFC unit 2 duty | 0.4 % | 99.6 % |
| RFC relay 2 | On | |
[ ]: HDS Parameter
Malfunction Threshold
Either of the condition occurs:
- The FAN_CONTROL_2 terminal voltage level is OFF (high voltage) for at least 12 seconds despite the PCM outputs ON signal to RFC unit 2.
- The FAN_CONTROL_2 terminal voltage level is ON (low voltage) for at least 12 seconds despite the PCM outputs OFF signal to the RFC unit 2.
Possible Cause
- RFC unit 2 FAN_CONTROL_2 line short to power
- RFC unit 2 FAN_CONTROL_2 line short to ground
- RFC unit 2 FAN_CONTROL_2 line open
- RFC unit 2 power supply line open
- RFC unit 2 failure
- PCM internal circuit failure
Confirmation Procedure
Operating Condition
- Turn the vehicle to the ON mode.
- Turn the vehicle to the OFF (LOCK) mode.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, a Confirmed DTC, the freeze data, and the on-board snapshot are stored. The MIL does not come on.
Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.