Code 22, TPS Signal Low: Notes

The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to throttle valve angle. Signal voltage will vary from less than about 1.25 volts at idle to about 4.5 volts at wide open throttle.

1. This test confirms Code 22 and tests if the fault is because of a hard failure or an intermittent condition. Code 22 will set if engine is running, TPS voltage is less than .2 volt for 2 seconds.
2. This simulates Code 21. If the ECM recognizes a high voltage signal and sets Code 21, the ECM and wiring are not at fault.
3. This checks for voltage to the ECM. If the ECM recognizes the voltage as over 4 volts, the ECM and TPS signal circuit are not at fault.
4. If 5-volt reference circuit is open or shorted to ground, there may also be a Code 34 stored.