DTC 22

DFI TPS Circuit:

Hard DFI Code 22:

IMPORTANT:
- If this code IS NOT displayed during the third pass of diagnostic codes, it is an intermittent failure and cannot be diagnosed using this procedure. For an intermittent code, refer to "Note on intermittents" at the end of this text
- The ECM supplies a 5.0 volt signal to pin C (circuit 474) of the Throttle Position Sensor (TPS) and supplies a ground path to pin B (circuit 476X). The TPS signal from pin 5 (circuit 417) is a variable voltage which is dependent on the throttle position.
- Trouble Code 22 indicates that the voltage signal from the TPS is too low. This situation can be observed in engine data display as a throttle angle reading (parameter .0.1) of -10° to -6° at part throttle. Possible causes of this condition are:
A. A defective throttle position sensor.
B. Defective wiring, terminals, etc.
C. An ECM which is unable to process signals properly.

1. If the opposite condition (high TPS signal) is created, then the self-diagnostics can be used to detect this failure by displaying engine data parameter .0.1. With the opposite condition created parameter .0.1 should display a throttle angle reading of 87° to 90°. To create a high TPS signal, disconnect the TPS connector and jumper circuit 417 (dark blue wire) and circuit 474 (gray wire) together at the TPS test point. If the throttle angle reading is now 87° to 90°, the fault must be improper mating of sensor terminals or a faulty TPS.
2. If the throttle angle reading is 86° or less, measure the voltage on circuit 474. If the voltmeter reads 0.0 volts, then the throttle position sensor is not receiving 5.0 volts and circuit 474 must be repaired for an open or short to ground.
3. If the voltmeter reads 5.0 volts, then while back probing measure the voltage between circuit 474 (dark blue wire) and circuit 417 (gray wire) at the TPS test point. If the voltage is 5 volts, check circuit 417 for a short to ground If the wiring is OK,then the fault must be in the ECM connector or ECM itself.
4. If the voltmeter does not read 5.0 volts, then an open must exist in either the wiring harness or the ECM. If the throttle angle reading is still 86° or less with circuits 474 and 417 jumpered together at the ECM, the fault must be in the ECM connector or ECM itself. If the reading is 87° to 90°, then circuit 417 is open.

Note on Intermittents:
- If an intermittent Code 22 is being set, manipulate related wiring while observing the engine data parameter .0.1. If the failure is induced, the throttle angle reading will jump from its normal value to the open reading of -10° to -6° at part throttle. This will help to isolate the location of the malfunction.