P1121

Circuit Description
The Throttle Position (TP) sensor circuit provides a voltage signal that changes relative to throttle blade angle. The signal voltage will vary from 1 volt at closed throttle to 4 volts at Wide Open Throttle (WOT). The TP signal is one of the most important inputs used by the PCM for fuel control and most of the PCM-controlled outputs. If the PCM detects a TP signal voltage that is intermittently greater than the range of the TP sensor, DTC P1121 will be set.

Conditions for Running the DTC
The ignition is ON.

Conditions for Setting the DTC
TP sensor intermittently indicates a throttle position signal greater than 4.9 volts.

Action Taken When the DTC Sets
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC
^ A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
Check for the following conditions:
^ Poor connection at the PCM or sensor. 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 throttle position display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the display will indicate the location of the malfunction.
If DTC P1121 cannot be duplicated, reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.