Throttle Position Sensor 1 Circuit High
P0123-THROTTLE POSITION SENSOR 1 CIRCUIT HIGH
For a complete wiring diagram, refer to the wiring information Electrical Diagrams.
- When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
- Set Condition:
The PCM detects that the Throttle Body input voltage is above the maximum acceptable value. One trip fault. Three good trips to turn off the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure
1. DTC IS ACTIVE
NOTE: Diagnose and repair any Throttle Body circuit, system voltage, or sensor supply voltage DTCs before continuing with this test.
1. Start the engine and allow it to reach operating temperature.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hand near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.
2. With the scan tool select View DTCs.
NOTE: If the DTC does not reset it may be necessary to test drive the vehicle.
NOTE: If the P2123-APP Sensor 1 Circuit High DTC is also Active, diagnose the P2123 before continuing with the P0123 diagnostic procedure.
Is the status Active for this DTC?
Yes
- Go To 2
No
- Refer to the CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking for an Intermittent DTC
2. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Throttle Body connector.
3. Disconnect the C2 Powertrain Control Module (PCM) harness connector.
4. Turn the ignition on.
5. Measure the voltage of the (F855) 5-volt Supply circuit in the Throttle Body harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (F855) 5-volt Supply circuit.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 3
3. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO VOLTAGE
1. Measure the voltage of the (K22) TP Signal 1 circuit in the Throttle Body harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (K22) TP Signal 1 circuit.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 4
4. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Measure the resistance between the (K22) TP Signal 1 circuit and the (F855) 5-volt Supply in the Throttle Body harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the short between the (K22) TP Signal 1 circuit and the (F855) 5-volt Supply circuit.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 5
5. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K124) ETC MOTOR (+) CIRCUIT
1. Measure the resistance between the (K22) TP Signal 1 circuit and the (K124) ETC Motor (+) in the Throttle Body harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the short between the (K22) TP Signal 1 circuit and the (K124) ETC Motor (+) circuit.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 6
6. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K126) ETC MOTOR (-) CIRCUIT
1. Measure the resistance between the (K22) TP Signal 1 circuit and the (K126) ETC Motor (-) in the Throttle Body harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the short between the (K22) TP Signal 1 circuit and the (K126) ETC Motor (-) circuit.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 7
7. (K22) TP SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE
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 PCM Pinout Box 8815 to perform diagnosis.
1. Measure the resistance of the (K22) TP Signal 1 circuit between the Throttle Body harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 8
No
- Repair the open in the (K22) TP Signal 1 circuit.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
8. (K922) TP SENSOR GROUND CIRCUIT OPEN OR HIGH RESISTANCE
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 PCM Pinout Box 8815 to perform diagnosis.
1. Measure the resistance of the (K922) TP Sensor Ground circuit between the Throttle Body harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 9
No
- Repair the open in the (K922) TP Sensor Ground circuit.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
9. THROTTLE BODY
1. Turn the ignition off.
2. Connect the C2 Powertrain Control Module (PCM) harness connector.
3. Connect a jumper wire between the (K22) TP Signal 1 circuit and the (K922) TP Sensor Ground circuit in the Throttle Body harness connector.
4. Turn the ignition on.
5. With a scan tool, read the Throttle Body voltage.
NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus.1 volt) with the jumper wire in place.
Does the scan tool display the voltage as described above?
Yes
- Replace the Throttle Body. After the installation is completed, perform the ETC RELEARN function on the scan tool.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Go To 10
10. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Search for any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM VERIFICATION TEST. PCM Verification Test.
No
- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM VERIFICATION TEST. PCM Verification Test.