PACCAR MX (2004 Emissions) Fault Code: P1054 Downhill Speed Control Switches – Data Erratic, Intermittent or Incorrect

PACCAR MX (2004 Emissions) Fault Code: P1054 Downhill Speed Control Switches – Data Erratic, Intermittent or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that both the downhill speed control activation and deactivation switches are active at the same time.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is on.

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

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:
Mechanical failure or damage to the downhill speed control switches

ADDITIONAL INFORMATION:
Downhill speed control keeps the desired vehicle speed at a constant level during descents.