Powertrain Controls - ECM/PCM

Diagnostic Trouble Code (DTC) 22:

Throttle Position Sensor Circuit:

CIRCUIT DESCRIPTION
The Throttle Position (TP) sensor provides a voltage signal that changes, relative to the throttle blade position. Signal voltage should vary from about 0.6 volt at idle to about 5 volts at Wide Open Throttle (WOT).

The TP sensor signal is one of the most important inputs used by the Powertrain Control Module (PCM) for fuel control and for most of the PCM controlled outputs.

DIAGNOSTIC TROUBLE CODE (DTC) 22 WILL SET WHEN
TP sensor signal voltage is less than about 0.23 volt.

ACTION TAKEN (PCM DEFAULT)
The Malfunction Indicator Lamp (MIL) will illuminate, transmission Torque Converter Clutch (TCC) will not apply, high transmission line pressure, harsh shifts, fixed shift points and no fourth gear in hot mode.

DTC CHART TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. The TP sensor has an auto zeroing feature. If the voltage reading is within the range of about 0.3 to 0.9 volt, the PCM will use that value as closed throttle. If the voltage reading is out of the auto zero range at closed throttle, check for a binding throttle cable and Traction Control System (TCS) adjuster assembly operation. Refer to Brakes and Traction Control for TCS adjuster diagnosis.

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

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

4. Before replacing any components, refer to Brakes and Traction Control for a detailed circuit description.

5. It the TP sensor or throttle body is replaced, the Electronic Brake and Traction Control Module (EBTCM) must "learn" the TP sensor idle position voltage with the new components installed. This is necessary to ensure effective engine torque reduction during TCS events. For TP sensor learn procedure, refer to refer to Powertrain Management / Computer and Control Systems / Throttle Position Sensor / Service and Repair / Throttle Position Sensor Learn Procedure. Idle Learn Procedure

DIAGNOSTIC AIDS
The Tech 1 Scanner displays throttle position in voltage and percentage of throttle blade opening. With ignition "ON" or at idle, TP sensor signal voltage should display between 0.3 and 0.9 volt with the throttle closed and increase at a steady rate as throttle is moved toward WOT.

An open or short to ground in CKT 416 or CKT 417 will result in a DTC 22.

Refer to Diagnosis By Symptom/Intermittents. - Intermittent Malfunctions