LOCKNUT 6P6698 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the accelerator pedal position sensor.This procedure covers the following diagnostic codes:
41-03 8 Volt Supply voltage high
41-04 8 Volt Supply voltage low
91-08 Throttle Position Invalid
91-13 Throttle Position out of calibrationThe accelerator pedal position sensor is used to provide a throttle position signal to the Engine Control Module (ECM). Sensor output is a constant frequency signal with a pulse width that varies with the pedal position. This output signal is referred to as either a duty cycle or a pulse width modulated signal (PWM) and this output signal is expressed as a percentage between 3 and 100 percent.The accelerator pedal position sensor is attached directly to the accelerator pedal assembly. The accelerator pedal position sensor requires no adjustment.The accelerator pedal position sensor will produce a duty cycle of 10 to 22 percent at low idle and 75 to 90 percent when the accelerator pedal is fully depressed. The percent of duty cycle is translated in the ECM into an accelerator pedal position of 3 to 100 percent.Note: When the ECM automatically calibrates new duty cycle values for the low idle throttle position and the high idle throttle position the ECM assumes 22 percent duty cycle at low idle and 75 percent duty cycle at high idle. As a result, you may notice that the throttle position status reaches 100 percent well before the accelerator pedal is fully depressed. This is normal. After some cycling of the accelerator pedal to the high idle position, the ECM will adjust the calibration automatically. The ECM will adjust the calibration automatically provided that the high idle stop position is within the 75 to 90 percent duty cycle range, and the low idle is in the 10 to 22 percent duty cycle range. During normal operation, you may also notice that more movement of the accelerator pedal is required for the throttle position status to increase above 3 percent. You may also observe that the status reaches the 100 percent value prior to the limit of the high idle position. This is done in order to ensure that the throttle reaches these two critical points for engine operation.The accelerator pedal position sensor is powered by the ECM supply voltage (+8 VDC) from connector P1-4 to terminal "A" of the accelerator pedal position sensor connector. The accelerator pedal position sensor can be replaced separately from the pedal assembly. An incorrectly calibrated pedal assembly can not be adjusted. The entire pedal assembly must be replaced.If the vehicle is in PTO mode, the accelerator pedal position sensor will be ignored while the engine is in PTO mode and the "PTO Configuration" is programmed to one of the following options:
Remote switches
Remote throttleNote: In the configuration for the cab switches, the vehicle's accelerator pedal can be used in order to control the engine rpm for the PTO operation. The accelerator pedal can also be ignored in the "Cab Switches" PTO configuration. Programming of customer parameters is required in order