DTC 22

Code 22 Wiring Diagram:

Code 22 - Throttle Position Sensor (Signal Voltage Low):

CIRCUIT DESCRIPTION:
The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from about .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 ECM for fuel control and for most of the ECM control outputs.

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 .2 volt
2. Simulates Code 21: (high voltage) If the ECM recognizes the high signal voltage then the ECM and wiring are OK.
3. This simulates a high signal voltage to check for an open in CKT C13. The "Scan Tool" will not read up to 12 volts, but what is important is that the ECM recognizes the signal on CKT C13.
3. There should be 5 volts at terminal "C" if measured with a DVM when ignition is ON.

DIAGNOSTIC AIDS:
A "Scan" tool reads throttle position in volts. Should read less than 1.25 volts with throttle closed and ignition "ON" or at idle. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT).
An open or short to ground in CKT C13 or CKT C14 will result in a Code 22.
See DIAGNOSIS BY SYMPTOM - NO TROUBLE CODES STORED.