P1121

DTC P1121

Circuit Description

The throttle position (TP) sensor is used by the powertrain control module (PCM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits:

* A 5-volt reference circuit
* A low reference circuit
* A TP sensor signal circuit

The PCM provides the TP sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Rotation of the TP sensor rotor from the closed throttle position to the wide open throttle (WOT) position provides the PCM with a signal voltage from below 1 volt to more than 4 volts through the TP sensor signal circuit. If the PCM detects an intermittent excessively high signal voltage, DTC P1121 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1121 Throttle Position (TP) Sensor Circuit Intermittent High Voltage

Conditions for Running the DTC

* DTC P0641 and P0651 are not set.
* The ignition is ON.
* DTC P1121 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The PCM detects that the TP sensor voltage is intermittently more than 4.9 volts.

Action Taken When the DTC Sets

* The control module stores the DTC information into memory when the diagnostic runs and fails.
* The malfunction indicator lamp (MIL) will not illuminate.
* The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
* The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

* A current DTC Last Test Failed clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
* Clear the DTC with a scan tool.

Test Description

Step 1 - Step 8:

Step 9 - Step 10:

The number below refers to the step number on the diagnostic table.
7. This test will determine an intermittent faulty TP sensor utilizing the MIN MAX, 100 millisecond capture mode on the DMM.