P1122

DTC P1122 TP Sensor CKT Intermittent Low Voltage




Circuit Description
The Throttle Position (TP) sensor is a three wire potentiometer using a 5 volt reference a ground and a signal circuit. The TP sensor signal circuit detects voltage changes on the potentiometer (variable resistor) as the throttle angle changes. The TP sensor signal voltage varies from 0.6 volts at idle to approximately 4.6 volts at wide open throttle. The TP sensor is one of the primary inputs to the VCM. Its input is important to most engine and transmission functions.

This DTC is designed to detect intermittent low signal voltage on the TP sensor signal circuit.

Conditions for Running the DTC
The engine is running.

The Conditions for Setting the DTC
The VCM detects an intermittent low TP sensor voltage while the engine is running.

Action Taken When the DTC Sets
The VCM stores the DTC in History if the VCM detects an intermittent problem.

Conditions for Clearing the MIL/DTC
- A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22 °C (40 °F) from the startup coolant temperature and the engine coolant temperature exceeds 70 °C (160 °F) during the same ignition cycle.
- Use the scan tool Clear Information function.

Diagnostic Aids
The scan tool reads throttle position in volts. The TP should read about 0.45 - 0.85 volts with the throttle closed and the ignition ON or at idle. The voltage should increase at a steady rate as the throttle is moved toward Wide Open Throttle (WOT).

Also, some scan tools will read the throttle angle. 0% = closed throttle. 100% = WOT.

An intermittent open or short to ground in the 5 volt reference circuit or the TP sensor signal circuit could result in a DTC P1122.

Monitor the TP sensor signal while depressing the accelerator pedal with the engine OFF and the ignition ON. The display should vary from about 0.5 volts (500 mV) when throttle was closed, to over 4.5 volts (4500 mV) when throttle is held at the Wide Open Throttle (WOT) position.

An intermittent may be caused by any of the following conditions:
- A poor connection
- Rubbed through wire insulation
- A broken wire inside the insulation

Thoroughly check any circuity that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis.

If a repair is necessary, then refer to Wiring Repairs or Connector Repairs.

Steps 1 - 3:

Steps 4 - 7:

Steps 8 - 9:

Test Description
The numbers below refer to the step numbers in the diagnostic table.
2. If the TP sensor voltage is less than 0.25 volts, then the conditions for the DTC are still present.
3. If any other non-intermittent DTCs are set go there first.