DTC 22

Code Chart 22:

TPS Circuit:

CIRCUIT DESCRIPTION:
The Throttle Position (TP) sensor provides a voltage signal that changes relative to the throttle blade. Signal voltage will vary from about .29 at idle to about 4.8 volts at Wide Open Throttle (WOT) and is non-adjustable.

The TP sensor 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: Number(s) below refer to circled number(s) on the diagnostic chart.

1. DTC 22, will set if:

^ Engine running.
^ TP sensor signal voltage is less than about .2 volt for 3 seconds.

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

3. TP sensor check: The TP sensor has an auto zeroing feature. If the voltage reading is within the range of .29 to .98 volt, 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 TP sensor, make sure the cruise control and throttle cables are not being held open. If OK, replace TP sensor.

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

5. CKTs 416 and 474 share a common 5 volts buffered reference signal. If either of these circuits is shorted to ground, DTC 22 will set. To determine if the MAP sensor is causing the DTC 22 problem, disconnect it to see if DTC 22 resets. Be sure TP sensor is connected and clear DTC(s) before testing.

DIAGNOSTIC AIDS:
A scan tool reads throttle position in volts. Voltage should increase at a steady rate as throttle is moved toward WOT.

Also, scan tools will read throttle angle. 0% closed throttle, 100% WOT.

An open or short to ground in CKTs 416 or 417 will result in a DTC 22. Also, a short to ground in CKT 474 will result in a DTC 22. - Intermittent Malfunctions