PACCAR PX-9 CM2350 (2013-17) Fault Code:1359 PID:91 SPN:91 FMI:4 Accelerator Pedal or Lever Position Sensor 1 Circuit – Voltage Below Normal or Shorted to Low Source

Reason:
Accelerator Pedal or Lever Position Sensor 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low voltage detected at accelerator pedal position number 1 signal circuit.

Effect:
The engine will operate in Limp Home mode

Circuit Description:
The accelerator position sensor is a Hall effect sensor attached to the accelerator pedal. The accelerator position sensor varies the signal voltage to the engine control module (ECM) as the accelerator pedal is depressed and released. Low signal voltage is received by the ECM when the accelerator pedal is at 0 percent. A high signal voltage is received by the ECM when the accelerator pedal is at 100 percent. The accelerator pedal position circuit contains an accelerator pedal position 5 volt supply, accelerator pedal position return, and accelerator pedal position signal.

The accelerator pedal contains two position sensors. These position sensors are used to measure the throttle position. Both position sensors receive a 5 volt supply from the ECM. A corresponding signal voltage based on the position of the accelerator pedal is then received from the ECM. The signal voltage for accelerator position 1 is twice as much as the signal voltage from the accelerator position 2.

Component Location:
The accelerator pedal or lever position sensor is mounted to the accelerator pedal assembly. Refer to the OEM service manual

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the accelerator pedal signal voltage was out of range low.

Action Taken When the Fault Code is Active:
The ECM logs the fault code immediately when the diagnostic runs and fails.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults.

Shop Talk:
Newer engines use two throttle position sensors to determine the throttle position. Older throttle pedals used a single throttle position sensor and an idle validation switch. If Fault Codes 1359 and 1241 are active when the accelerator pedal is in the idle position, and Fault Code 1359 goes inactive, and Fault Code 1239 goes active when the throttle is depressed, the incorrect throttle pedal has been installed in the vehicle. A throttle pedal with two acceleration position sensors must be installed.

The accelerator pedal or lever position sensor signal voltage can be monitored with INSITE™ electronic service tool, while flexing the harness to locate the intermittent connection. Intermittent connections will show up as abrupt changes in signal voltage displayed by INSITE™ electronic service tool.

NOTE: The three wires in the accelerator position sensor circuit must be twisted together.

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

Possible Causes:
1) Accelerator pedal or lever position signal shorted to engine ground or return wires in the
2) OEM harness or sensor
3) Damaged accelerator pedal or lever position sensor
4) Open circuit in the accelerator signal, supply, or return wire in the harness or connectors