With TBI

Code 22 Chart:

Wiring Diagram For TPS:

CIRCUIT DESCRIPTION:

The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to the throttle blade angle. Signal voltage will vary from about 1.25 volts 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 controlled outputs.


TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. This checks to see if a Code 22 is the result of a hard code failure or an intermittent problem.
A Code 22 will set under the following conditions:
a. The engine running.
b. TPS signal voltage is less than 0.2 volts (200 mV).

2. Simulates a Code 21, high voltage. If a Code 21 is set, or the "Scan" tool displays over 4.0 volts, the ECM and wiring are OK.

3. The "Scan" tool may not display 5.0 volts, but the ECM should recognize the voltage being over 4.0 volts, indicating that circuit 417 and the ECM are OK.

4. If circuit 416 is shorted to ground, there may be a Code 34 stored.


DIAGNOSTIC AIDS:

1. A "Scan" tool displays TPS in volts. Closed throttle voltage should be less than 1.25 volts, and the voltage value should increase at a steady rate as the throttle is opened to WOT.
2. An open or grounded circuit 416 or 417 will result in a Code 22. If a Code 22 is intermittent, see DIAGNOSIS BY SYMPTOM.