Powertrain Controls - ECM/PCM

Code 22 Chart:

Throttle Position Sensor (TPS) Wiring Diagram:

CIRCUIT DESCRIPTION:

The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from about 0.5 at idle to about 5 volts at Wide Open Throttle (WOT). The TPS signal is one of the most important inputs used by the Electronic Control Module (ECM) for fuel control and for most of the ECM control outputs.

NOTE: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to SCHEMATIC DIAGRAMS/ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS/ECM CONNECTOR IDENTIFICATION for correct color code identification of circuit.

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

1. Code 22 will set if engine running, TPS signal voltage is less than about 0.2 volt for 3 seconds.

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

3. TPS: With throttle closed, the TPS voltage reading should be between 0.36 and 0.96 volts.

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

DIAGNOSTIC AIDS:

A "Scan" tool reads throttle position in volts. Should read between 0.36 and 0.96V with throttle closed and ignition "ON" or at idle. Voltage should increase at a steady rate as throttle is moved toward WOT. An open or short to ground in CKTs 416 or 417 will result in a Code 22. Refer to TESTING PROCEDURES/DIAGNOSIS BY SYMPTOM/INTERMITTENTS.