Powertrain Controls - ECM/PCM

DTC 22 Throttle Position Sensor:

Throttle Position Sensor Wiring Diagram:

Circuit Description:

The Throttle Position (TP) sensor provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from about 0.5 at idle to about 4.8 volts at Wide Open Throttle (WOT).

The TP sensor signal is one of the most important inputs used by the ECM for fuel control and for many of the ECM control outputs.

Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. DTC 22 will set if:

^ Engine running and RPM greater than 400.
^ TP sensor Signal voltage is less than about 0.20 volt for 3 seconds.

2. Simulates DTC 21: (high voltage) If the ECM recognizes the high signal voltage,. the ECM and wiring Care OK.

3. Check for good sensor connection. If connection is good, replace TP sensor.

4. This simulates a high signal voltage to check for an open in CKT 417.

5. CKT 416 is a 5 volts buffered reference signal. If CKT 416 is shorted to ground, DTC 22 will set. To determine if the MAP sensor is causing the DTC 22 problem, disconnect it to see if DTC 22 resets. Be sure TP sensor is connected and clear DTC(s) before testing.

Diagnostic Aids:


A scan tool reads throttle position in volts. Voltage should increase at a steady rate as throttle is moved toward WOT.

Also some scan tools will read:

Throttle angle 0% = Closed throttle
Throttle angle 100% = WOT.

An open or short to ground in CKTs 416 or 417 will result in a DTC 22.

Scan TP sensor while depressing accelerator pedal with engine stopped and ignition "ON." Dissplay should vary from about 0.5 volt when throttle was closed, to about 4.8 volts when throttle is held at Wide Open Throttle (WOT) position.

If DTC 22 is set, check CKT 416 for faulty wiring or connections. - Intermittent Malfunctions