P0122

DIAGNOSTIC TROUBLE CODES P0122, P0123
Throttle position sensor, control module input, open circuit or shorting to ground/batt+.

Fault Symptom.
CHECK ENGINE lamp (MIL) on.
A/C does not work.
Performance down.

Condition
In the event of a short circuit or open circuit a diagnostic trouble code will be generated.

Diagnostic Procedure.
1. Check the operation of the throttle position sensor an the ISAT scan tool.
Ignition switch in the ON position.
Select "READ FUNCTIONS".
Select "THROTTLE POS SENSOR".
At idling speed the Scan Tool should show a reading of about 0.5 V which should, as the throttle is opened, successively increase to about 4.5 V at wide open throttle.

If the reading is OK, continue with step 2.
If the Scan Tool shows a reading of about 0 V (shorting to ground) or 5 V (open circuit), continue with step 3.

2. Depress the accelerator very slowly. Depressing it from its idle position (not depressed) to the fully depressed position should take about 20-30 seconds. Observe the Scan Tool display during this process.
Nominally, the Scan Tool display should show a continuous increase from about 0.5 V to about 4.5 V.
If there is an internal fault in the throttle position sensor, an open circuit will show about 5 V and shorting to ground 0 V for a brief period.

If the measured value is incorrect, fit a new throttle position sensor.
If the measured value is correct, continue with step 5.





3. Check the electrical interface in the throttle position sensor's connector.
Unplug the 3-pin connector.
Ignition switch in the ON position.
Carry out the following three checks:
Voltage measurement in the female connector:
- across pin 2 and battery negative ____ about 5 V.
- across pin 1 and battery positive ____ about 12 V.
- Select "READ FUNCTIONS",
Select "THROTTLE POS SENSOR".
The Scan Tool should show a reading 0 V.
Connect a jumper lead across pins 1 and 3.
The Scan Tool should show 5 V.

If all readings are OK, check the throttle position sensor connector for corrosion and possibly remedy it.
If no remedy is possible, fit a new throttle position sensor.
If any measured value is incorrect, continue with step 4.

4. The throttle position sensor's electrical connection is faulty.
Check The Wiring between the control module and the 3-pin connector of the throttle position sensor for continuity, shorting and possible stray currents.

If the measured values are correct, continue with step 5.

5. Clear the diagnostic trouble code and drive the car to see whether the DTC is generated again.

If the diagnostic trouble code is generated again, continue at "Procedure Before ECM Replacement". Component Tests
If the trouble code is not generated again the remedial measure taken was correct, otherwise the fault is of intermittent type.