Action Taken

WARNING: This page is about a different car, the 1990 Cadillac Fleetwood and 1990 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

ECM turns on SERVICE SOON light.
ECM disables VCC.
ECM uses 13 degrees for TPS value with ISC throttle switch open, and 6 degrees for TPS value when ISC throttle switch closes.

The TPS is a 3-wire sensor or potentiometer with 5-volt reference input from ECM to sensor circuit No. 474. This is a reference ground from ECM to sensor circuit No. 476, and a sensor output signal circuit No. 417 from sensor to ECM. The sensor output signal is a DC voltage that varies with throttle angle. At low throttle angle, TPS signal voltage is low (about .5 volt at minimum air setting). At high throttle angle, the TPS signal voltage is high (about 4.5 volts) at wide open throttle.

Code E22 is set when ECM sees a throttle angle that is out of limits (low TPS voltage) with engine running at idle or faster. The code is designed to detect a TPS signal circuit No. 417 open to ECM terminal D7.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Test Number 1) Check for shorted TPS or shorted wiring. If data value stays greater than -7 with TPS disconnected, problem is in wiring.

Test Number 2) Check for an open circuit No. 476 between TPS and ECM. An open circuit will result in high TPS values whenever TPS is plugged in.