With 4L80E Automatic Transmission

Throttle Position Sensor Circuit Code 22:

Throttle Position Sensor Circuit:

Circuit Description:
The Throttle Position sensor (TPS) provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from about .5 volt at idle to about 4.0 volts at Wide Open Throttle (WOT).
The TPS signal is one of the most important inputs used by the PCM for fuel control and for most of the PCM control outputs.

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

1. Code 22 will set if:
^ Engine running.
^ TPS signal voltage is less than about .2 volt for 1 second.

2. Simulates Code 21: (high voltage) If the PCM recognizes the high signal voltage the PCM and wiring are OK.

3. This step checks for a poor connection or faulty TP sensor. Replace TP sensor if faulty.

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


Diagnostic Aids:
A Tech 1 "Scan" tool reads throttle position in volts and should read about .45 to 1.25 volts with throttle closed and ignition "ON" or at idle. Voltage should increase at a steady rate as throttle is moved toward WOT.

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

- Intermittent Malfunctions

"Scan" TPS while depressing accelerator pedal with engine stopped and ignition "ON". Display should vary from below 1.25 volts (1250 mV) when throttle was closed, to over 4.0 volts (400 mV) when throttle is held at Wide Open Throttle (WOT) position.