ECM Code EO22: Open TPS Circuit: Action:

ECM turns on SERVICE ENGINE SOON light and disables viscous converter clutch. ECM uses 6 degrees for TPS value when ISC throttle switch closes. ECM uses 13 degrees for TPS value when ISC throttle switch opens.

The TPS is a 3-wire sensor receiving a 5-volt reference input from ECM over circuit No. 474, and a reference ground from ECM over circuit No. 976. The TPS sensor sends a sensor output signal over circuit No. 417 to the ECM.

The sensor output signal is a D voltage that varies with throttle angle, the TPS signal voltage is low (about .5 volt at minimum air setting). At high throttle angles, the TPS signal voltage is high (about 4.5 volts at wide open throttle).

Code EO22 is set when the ECM sees throttle angle is out of limits (low TPS voltage) with engine running at idle or faster. Code is designed to detect a TPS signal, over circuit No. 417, open to ECM terminal F13.

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

Test Number 1) Checks for shorted TPS or wiring. If data value stays the same with the TPS disconnected, the problem is in the wiring.

Test Number 2) Checks for an open in circuit No. 976 between the TPS and ECM. An open will cause TPS signal to be high whenever the TPS is plugged in.