DTC 22

CIRCUIT DESCRIPTION
The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from about 0.5 at idle to 4.5 volts at wide open throttle.

The TPS signal is one of the most important inputs used by the Engine Control Module (ECM) for fuel control and for most of the ECM controlled outputs.

The back-up mode signal is used only for calibrating fuel delivery in the ECM back-up mode.

Code 22 will set if:
^ Engine running
^ TPS signal voltage is less than about 0.2 volt for 3 seconds.


CHART TEST DESCRIPTION
1. Confirms code 22, and that fault is present.

2. Simulates Code 21: If the ECM recognizes the high signal voltage and sets Code 21 the ECM and wiring are OK.

3. Checks for reference voltage from the ECM. To prevent damage to ECM, be sure to disconnect C-D connector when checking circuit wiring for open or shorts to ground.

4. TPS adjustment: With throttle closed the TPS voltage reading between terminals A & B should be 0.55V +/- 0.05V.