P0123

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Throttle Position (TP) sensor is a potentiometer. The TP sensor is mounted to the right side of the throttle body. The TP sensor provides a voltage signal that changes relative to throttle blade angle. This signal voltage is one of the most important inputs used by the PCM. The TP sensor has a 5.0 volt reference, a ground and a signal circuit. TP sensor Signal voltage should be about 0.6 volt at idle. The TP sensor voltage should increase to above 4.0 volts at wide open throttle (WOT). When the PCM senses a signal voltage higher than the normal operating range of the sensor, this DTC will set.

CONDITIONS FOR SETTING THE DTCSelling The DTC

^ TP sensor signal voltage is greater than 4.8 volts.

^ Condition present for 1 second.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM will illuminate the\ Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

^ The PCM will use a default TP sensor value.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and/or Failure Records.

^ Transmission TCC will not apply.

^ High transmission line pressure.

^ Fixed transmission shift points, hard shifts and no fourth gear in hot mode.
CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

^ A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.

^ A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

^ PCM battery voltage is interrupted.

^ Using a Scan tool.

DIAGNOSTIC AIDS

^ An intermittent may be caused by the following:

- Mis-routed harness.

- Rubbed through wire insulation.

- Broken wire inside the insulation.

^ If other DTCs are set that share the same ground and/or 5.0 volt reference circuit, check for faulty connections and for faulty wiring.

^ The PCM 5 volt reference circuits are internally connected within the PCM. If all the TP sensor circuits check to be OK, inspect related 5.0 volt reference circuits.

^ If it is determined that the DTC occurs intermittently, performing the DTC P1121 diagnostic table may isolate the cause of the fault.

For intermittents, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

2. This checks if the fault is present.

3. Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed.

4. Vehicles equipped with traction control will have to disconnect the EBTCM. This will determine if the short is caused from the EBTCM. After repairs are made, reconnect the EBTCM, clear any DTCs that may have been set when the EBTCM was disconnected.

6. This checks whether the ground circuit is available to the TP sensor. Check for poor electrical connections at the TP sensor. Refer to Repair Procedures in Electrical Diagnosis (SA Cell 5).