Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- ACTIVE DTC NOTE:
Diagnose and repair any system voltage or sensor reference voltage DTCs before continuing with this test.
- Start the engine and allow it to reach normal operating temperature.WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
- With the scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- Start the engine and allow it to reach normal operating temperature.
- CHECK FOR THE (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO ANOTHER VOLTAGE SUPPLY CIRCUIT
- Turn the ignition off.
- Disconnect the Throttle Body harness connector.
- Disconnect the PCM C2 harness connector.CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Using the wiring diagram as a guide, measure the resistance between the (F855) 5-Volt Supply circuit and all other 5 volt and 12 volt circuits at the GPEC Adaptor.
Is the resistance between the (F855) 5-Volt Supply circuit and all other 5 volt and 12 volt power supply circuits above 10k Ohms?
Yes
- Repair the (F855) 5-Volt Supply circuit for a short to the circuit that measured below 10k Ohms.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 3
- CHECK FOR THE (K122) THROTTLE POSITION SENSOR SIGNAL 2 CIRCUIT SHORTED TO ANOTHER VOLTAGE SUPPLY CIRCUIT
- Using the wiring diagram as a guide, measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and all other 5 volt and 12 volt power supply circuits at the GPEC Adaptor.
Is the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and all other 5-volt and 12-volt power supply circuits above 10k Ohms?
Yes
- Go To 4
No
- Repair the (K22) Throttle Position Sensor Signal 1 circuit for a short to the circuit that measured below 10k Ohms.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Using the wiring diagram as a guide, measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and all other 5 volt and 12 volt power supply circuits at the GPEC Adaptor.
- CHECK FOR THE (K122) THROTTLE POSITION SENSOR SIGNAL 2 CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT
- Measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and the (F855) 5-Volt Supply in the Throttle Body harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 5
No
- Repair the (K122) Throttle Position Sensor Signal 2 circuit for a short to the (F855) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and the (F855) 5-Volt Supply in the Throttle Body harness connector.
- CHECK FOR THE (K122) THROTTLE POSITION SENSOR SIGNAL 2 CIRCUIT SHORTED TO THE (K447) ETC MOTOR (+) CIRCUIT
- Measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and the (K447) ETC Motor (+) in the Throttle Body harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 6
No
- Repair the (K447) ETC Motor (+) circuit for a short to the (K122) Throttle Position Sensor Signal 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and the (K447) ETC Motor (+) in the Throttle Body harness connector.
- CHECK FOR THE (K122) THROTTLE POSITION SENSOR SIGNAL 2 CIRCUIT SHORTED TO THE (K448) ETC MOTOR (-) CIRCUIT
- Measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and the (K448) ETC Motor (-) in the Throttle Body harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 7
No
- Repair the (K122) Throttle Position Sensor Signal 2 circuit for a short to the (K448) ETC Motor (-) circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between the (K122) Throttle Position Sensor Signal 2 circuit and the (K448) ETC Motor (-) in the Throttle Body harness connector.
- CHECK THE (K922) THROTTLE POSITION SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
- Measure the resistance of the (K922) Throttle Position Sensor Ground circuit between the Throttle Body harness connector and the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 8
No
- Repair the (K922) Throttle Position Sensor Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance of the (K922) Throttle Position Sensor Ground circuit between the Throttle Body harness connector and the GPEC Adaptor.
- THROTTLE BODY
- Turn the ignition off.
- Reconnect the PCM C2 harness connector.
- Connect a jumper between the (K922) Throttle Position Sensor Ground circuit and the (K122) Throttle Position Sensor Signal 2 circuit in the Throttle Body harness connector.
- Turn the ignition on.
- With the scan tool, read the Throttle Position Sensor Signal 2 circuit voltage.
Is the voltage below 0.1 volt with the jumper in place?
Yes
- Replace the Throttle Body in accordance with the service information. Refer to THROTTLE BODY, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 9
- POWERTRAIN CONTROL MODULE (PCM)
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the Powertrain Control Module (PCM).
- Look for any chafed, pierced, pinched, or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals.
- Monitor the scan tool data relative to this circuit and wiggle the wiring and connectors.
- Look for the data to change or for the DTC to reset during the wiggle Test.
- Perform any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Replace and program the Powertrain Control Module (PCM) in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.