DTC 22

Code 22 Chart:

Throttle Position Sensor Circuit Wiring Diagram:

CIRCUIT DESCRIPTION:


The throttle position sensor (TPS) provides a voltage signal that changes relative to the throttle opening. Signal voltage will vary from about 0.5 volt at idle to about 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 control outputs.

NOTE: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to ECM CONNECTOR IDENTIFICATION under ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS 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 is running.
^ TPS signal voltage is less than about 0.2 volt for 3 seconds.

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

3. TPS Check. The TPS has an auto zeroing feature. If the voltage reading is within the range of 0.400 to 0.900 volts, the ECM will use that value as closed throttle. If the voltage reading is out of the auto zero range on an existing or replacement TPS, the TPS should be replaced.

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


DIAGNOSTIC AIDS:


^ "Scan" TPS while depressing accelerator pedal with engine stopped and ignition "ON". Display should vary from about 500 mV (0.5 volt) when throttle is closed, to over 4500 mV (4.5 volts) when throttle is held wide open.

^ Also, some "Scan" tools will display throttle angle %: 0% = closed throttle; 100% = WOT.

^ If Code 22, 33 and/or 66 are set, check CKT 416 for faulty wiring or connections.

^ Should check condition of connector and sensor terminals for corrosion, and clean and/or replace as necessary. If corrosion is found, check condition of connector seal and repair or replace if necessary.

^ Refer to TESTING PROCEDURES/DIAGNOSIS BY SYMPTOM/INTERMITTENTS.