The brake pedal is pressed or fails. Accelerating the speed and engine power are limited. One trip fault code and installs within 5 seconds. And so light blinks. Possible causes (F855) 5-volt power supply chain breakage (F855) 5-volt power supply shorted to ground (K23) APP No. 1 signal-chain sensor open (K23) APP # 1 sensor signal circuit shorted (K23) APP sensor no. 1 signal circuit shorted in the APP (K167) sensor no. 1 return circuit (K23) APP sensor no. 1 signal circuit shorted (K400) Appendix # 2 return the APP sensor PCM schemes always follow the troubleshooting of the PKK before continuing. DIAGNOSTIC TEST 1. APP sensor below 0.25 Volts, ignition, engine not running.
With scan tool read the # 1 APP voltage sensor. Question: is the voltage below 0.25 volts? Yes: go to 2 No 11: go to 2. Food chain (F855) 5-Volt when monitoring: with the ignition on and no other APPS # 1 DTCS present. Set condition: when the APP # 1 sensor voltage too low. The engine will idle, if turn ignition off. Disconnect the sensor connector APP strap. Ignition on, engine not running. Measure the voltage on the power supply circuit (F855) 5-volt in-APP sensor connectors. Question: is the voltage between 4.5 and 5.2 volts? Yes: do not go 3: jump to 8 3. ACCELERATOR PEDAL POSITION SENSOR
