PACCAR MX (2004 Emissions) Fault Code: U17A9 Accelerator Pedal Operation – Data Erratic, Intermittent or Incorrect
PACCAR MX (2004 Emissions) Fault Code: U17A9 Accelerator Pedal Operation – Data Erratic, Intermittent or Incorrect
SET CONDITIONS:
The PCI ECU (D420) detects that the accelerator pedal is depressed above 2.6% while no driver is present.
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. To validate the repair, monitor the accelerator pedal sensors with the diagnostic service tool.
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:
Faulty accelerator pedal or wiring
ADDITIONAL INFORMATION:
1. The PCI ECU is able to detect if a driver is present in the vehicle, based on the accelerator pedal, foot brake pedal and vehicle speed inputs.
2. The accelerator pedal position is determined by two sensors (1 and 2) inside the accelerator pedal. The sensor outputs are PWM signals at a fixed frequency of 180 to 220 Hz. Sensor signals 1 and 2 are reversed compared to each other, meaning that by pressing the accelerator more, sensor 1 shows a decreasing PWM signal and sensor 2 shows an increasing PWM signal. The PCI ECU monitors both sensors separately and together.
