P0122

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The PCM supplies a 5V reference signal and a ground to the Throttle Position (TP) sensor. The TP sensor sends a voltage signal back to the PCM relative to throttle blade opening. Voltage will vary from 0.20 V at closed throttle to over 4.5 V at wide open throttle.

CONDITIONS FOR SETTING THE DTC

^ The TP sensor reads less than 0.20V for 6.25 seconds.

^ The engine is running.

ACTION TAKEN WHEN THE DTC SETS

^ The Malfunction Indicator Lamp (MIL) illuminates.

^ The PCM records the operating conditions at the time the diagnostic fails. This information will be stored in The Freeze Frame and Failure Records buffers stores this information.

^ A history DTC is stored.

^ The TP angle will default to 0% when the vehicle speed is less than 2 mph. The TP angle defaults to 10% when the vehicle speed is greater than 2 mph. The scan tool shows the defaulted value.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs without a fault.

^ A history DTC will clear after 40 consecutive warm up cycles without a fault.

^ A scan tool can clear the DTCs.

DIAGNOSTIC AIDS

Whenever this DTC cannot be duplicated, use the information included in the Freeze Frame data in order to evaluate the conditions when the DTC set.

A faulty A/C sensor could set a DTC P0122. Disconnect the A/C electrical connector. If the TP reading returns to normal, replace the A/C Refrigerant Sensor.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored in the scan tool for later reference.

2. The TP sensor has an auto zeroing feature. If the voltage reading is between 0.20 V and 0.90 V, the PCM will automatically assume this as closed throttle position (0%).

4. Simulates a DTC P0123. If the PCM recognizes the high voltage signal, then the PCM and wiring are OK.

5. This simulates a high voltage signal which will identify an open in the signal circuit.

6. If additional DTCs are set, check the 5 V reference circuits for a short to ground.

8. If the test light illuminates while probing the TP signal circuit, then the TP signal circuit is shorted to ground.

11. Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for PCM reprogramming and also refer to the Crankshaft Position (CKP) System Variation Learn Procedure for the Crankshaft Position System Variation Procedure.