P0123

Throttle Position (TP) Sensor Circuit High Voltage:

Throttle Position (TP) Sensor Circuit High Voltage (continued):

Throttle Position (TP) System:

Circuit Description

The Throttle Position (TP) sensor has a potentiometer whose resistance changes along with the throttle valve position. The Powertrain Control Module (PCM) provides a 5 volt reference voltage to the TP sensor. The PCM reads the voltage across the TP sensor and converts it into throttle position. When the TP sensor resistance decreases, the throttle valve opening is increasing to wide open throttle, and the voltage being monitored at the PCM increases. When the TP sensor resistance increases, the throttle valve opening is decreasing to idle, and the voltage being monitored at the PCM decreases.


Conditions for Setting the DTC

^ High voltage input at the PCM indicated with the engine running (greater than 96%).

^ Above condition is met for at least 0.5 seconds.


Action Taken When the DTC Sets

^ The Malfunction Indicator Lamp (MIL) will illuminate.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.


Conditions for Clearing the MIL/DTC

^ The MIL will turn "OFF" after three consecutively passing cycles without a fault present.

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

^ DTC(s) can be cleared by using a scan tool or by disconnecting the PCM battery feed.

Diagnostic Aids

Check The Following Conditions:

^ Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

^ Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the TP display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the TP display will indicate the location of the fault.

^ A mis-adjusted TP sensor could cause the malfunction to set. Refer to TP sensor.

^ DTC P0108, P0113, P0118, P0123 are set together it is possible to have an open ground circuit (LT. GRN/BLK wire).

^ Before replacement of the TP sensor check the resistance of the TP sensor, between terminals 1 and 4 - 2.87 to 5.33k ohms, terminals 1 and 3 - 100 to 20k ohms, if not within these values, replace TP sensor.

If DTC P0123 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

If any wiring repairs need to be made, Refer to Repair Procedures in Diagrams.

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 data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Observing the TP sensor parameter from closed throttle position to wide open throttle the percentage of the TP sensor movement should not be greater than 95%.

11. Refer to TP sensor adjustment procedures.