DTC 22

Code 22 - Throttle Position Sensor (TPS) Circuit (Signal Voltage Low):

Wiring Diagram For Code 22 - Throttle Position Sensor (TPS) Circuit (Signal Voltage Low):

CODE 22 - THROTTLE POSITION SENSOR (TPS) 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 at idle to about 4.5 volts at Wide Open Throttle (WOT).

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



Test Description: Numbers below refer to circled numbers on the diagnostic chart.

1. Code 22 will set if:

^ Engine is running
^ TPS signal voltage is less than about .2 volt

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

3. TPS check. The TPS has an "Auto Zeroing" feature. This means that the ECM has the ability to auto-zero the TPS voltage, if it is below about 1.25 volts at idle. The ECM will use this value to be 0% throttle. The TPS is not adjustable. If the TPS voltage is out of the "Auto Zeroing Range," check for binding or sticking cruise control or throttle cables. If OK, replace the TPS.

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



Diagnostic Aids:

A "Scan" tool reads throttle position in volts. Should read less than 1.25 volts with throttle closed and ignition "ON" or at idle. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT).

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

See Diagnosis By Symptoms - No Trouble Codes Stored.