Diagnostics Procedures
- Ignition on, engine not running.NOTE: If P0642 or P0643 are set along with P0123, diagnose the 5-volt supply DTCs before continuing.
With the DRBIII®, read the DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
- Yes --> Go To 2
- No --> Go To 10
- Was the P0222-TP SENSOR NO. 2 VOLTAGE LOW DTC set along with the P0122?
- Yes --> Go To 3
- No --> Go To 6
- Turn the ignition off.
Disconnect the Throttle Body harness connector.
Ignition on, engine not running.
Measure the voltage on the (F855) 5-volt Supply circuit in the Throttle Body harness connector.
Is the voltage between 4.8 and 5.2 volts?
- Yes --> Go To 6
- No --> Go To 4
- Turn the ignition off.
Disconnect the PCM harness connectors.
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 MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.Measure the resistance of the (F855) 5-volt Supply circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
- Yes --> Go To 5
- No --> Repair the open in the (F855) 5-volt Supply circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- Measure the resistance of the (F855) 5-volt Supply circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 100 ohms?
- Yes --> Repair the short to ground in the (F855) 5-volt Supply circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- No --> Go To 9
- Yes --> Repair the short to ground in the (F855) 5-volt Supply circuit.
- With the DRBIII®, monitor the TP Sensor No. 1 voltage with the harness connector still disconnected.
Is the voltage above 4.5 volts?
- Yes --> Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, with the DRBIII® under the Misc. Menu select ETC RELEARN.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- No --> Go To 7
- Yes --> Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, with the DRBIII® under the Misc. Menu select ETC RELEARN.
- Turn the ignition off.
Disconnect the PCM harness connectors.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WELL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.Measure the resistance between ground and the (K22) TP Sensor No. 1 Signal circuit at the appropriate terminal of special tool #8815.
Is the resistance below 100 ohms?
- Yes --> Repair the short to ground in the (K22) TP Sensor No. 1 Signal.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- No --> Go To 8
- Yes --> Repair the short to ground in the (K22) TP Sensor No. 1 Signal.
- Measure the resistance between the (K22) TP Sensor No. 1 Signal circuit and the (K922) Sensor Return circuit between the appropriate terminals of special tool #8815.
Is the resistance below 100 ohms?
- Yes --> Repair the short between the (K922) Sensor Return circuit and the (K22) TP Sensor No. 1 Signal circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- No --> Go To 9
- Yes --> Repair the short between the (K922) Sensor Return circuit and the (K22) TP Sensor No. 1 Signal circuit.
- Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
If there are no possible causes remaining, view repair.
- Repair
- Replace and program the Powertrain Control Module per Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- Replace and program the Powertrain Control Module per Service Information.
- Repair
- With the DRBIII®, perform the Throttle Follower Test.
Monitor the TP Sensor No. 1 voltage while slowly pressing the Throttle pedal down.
Is there a smooth voltage change from low to high?
- Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure).
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- No --> Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, with the DRBIII® under the Misc. Menu select ETC RELEARN.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
- Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure).