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David 4/10/2018

1989 GMC S15 Sierra Classic 6 Cyl 4.30L


1989 4.3 setting tps code 22

1989 4.3 keeps setting 22 code. Tps low voltage. Replaced the tps twice. Replaced the ECM. Still setting code. Tps wiring testing good. Will not set code when first started. Only after engine has heated up. Any ideas?

1 Answer


Jimm 4/10/2018

GM OBD Trouble Code 22
Throttle Position Sensor Error (Signal Low)
The Throttle Position sensor signals the Engine Control Module as to the current position of the engine throttle valve. The current throttle valve opening is based on the driver's input from the gas pedal. The ECM uses the information from this sensor to help calculate fuel delivery and spark timing.

Fault Code Description

22 - Throttle Position sensor error (signal low, shorted circuit)


Extended cranking, possible no-start condition
Lack of power
Erratic transmission operation

Common Problems

A failed Throttle Position Sensor (TPS) would be the most common causes for code 22
Testing the TPS circuit would involve checking voltage and ground from the ECM-5v is the normal reading between the ECM reference circuit and the ECM ground circuit at the TPS connector. Checking the TPS signal circuit to the ECM would involve monitoring the TPS signal on a scan tool while jumping the 5v reference and the signal circuits. The TPS reading should go from high when the circuit is "jumpered" to low when the jumper is removed.


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