Powertrain Controls - ECM/PCM

DTC 22 Chart:

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor provides a voltage signal that will change relative to the throttle blade an angle. The signal voltage will vary from about 0.4 volt at idle to about 5 volts at wide open throttle. The PCM calculates throttle angle in percentage from the TP sensor voltage signal and auto zeros from about 0.4 volt (0%) to about 5 volt (100%). The TP sensor is one of the most important inputs used by the PCM for fuel control and other functions such as idle, Wide Open Throttle (WOT), deceleration enleanment, and acceleration enrichment. When the PCM detects a TP signal below the low limit and engine RPM is 600 or greater, DTC 22 will set.

DTC 22 WILL SET WHEN
- RPM is 600 or greater.
- TP sensor voltage is 0.1 or less.

ACTION TAKEN (PCM WILL DEFAULT TO)
- With a current DTC 22 set, the PCM will illuminate the Malfunction Indicator Lamp (MIL) (Service Engine Soon).
- The PCM will disable the Torque Converter Clutch (TCC), and transaxle pressure control. The transmission will be locked in the current gear, TP, throttle angle value will be replaced with a default of 6°(7%) with a closed throttle switch and 13°(16%) with throttle switch open.

DTC 22 WILL CLEAR WHEN
The fault no longer exists.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. If DTC 32 or 36 are also set CKT 474 must be open or shorted to ground because TP sensor and MAP sensor share the same 5 volt signal.
2. With TP sensor or wiring open, Tech 1 data parameter "RAW THROTTLE POS" with read -5 or less.
3. Checking for open TP sensor or open wiring. If the data value stays less than 85 with the TP sensor terminals "A" and "C" jumpered together, the problem is in the wiring.
4. Voltage should be greater than 0.5 volt if CKT 474 is not open or shorted to ground.
5. Checking if CKT 474 is open or if CKT 417 is shorted to ground.
6. Checking if signal is reaching PCM. If signal is reaching PCM, then the fault is with the PCM.

DIAGNOSTIC AIDS
The Tech 1 displays throttle position in volts. Voltage should increase at a steady rate as throttle is move toward WOT.
An open or short to ground in CKT 474 or 417 will result in DTC 22.
Check for:

Poor connection or damaged harness
Inspect PCM harness connectors for backed out terminal "B15" and/or "C1", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

Intermittent test
Monitor TP sensor voltage display while moving related connectors and wiring harness. If the failure is induced, the display will change. This may help to isolate the location of the malfunction.

TP sensor scaling
Observe TP sensor voltage display while depressing accelerator pedal, with engine stopped and ignition "ON." Display should vary from closed throttle TP sensor voltage when throttle is closed (0.4 volt) to over 5 volts when throttle is held at Wide Open Throttle (WOT) position.