PACCAR MX (2004 Emissions) Fault Code: P0527 Fan Speed – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that the fan speed is higher than the engine speed.

DIAGNOSTIC CONDITION:
The diagnostic runs when the engine speed is above 1200 rpm.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
The DTC changes to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back?
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. The sensor or actuator signal wiring has a short circuit to supply.
2. A malfunction of the sensor or actuator