Operation CHARM: Car repair manuals for everyone.

Signal Too Low. Permanent Fault





Checking Power Cable
- Ignition off.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Disconnect throttle position sensor.

NOTE: If the engine cooling fan continues operating after engine has been switched off, it must be allowed to stop before resistance measurements are taken.

- Connect an ohmmeter between throttle position sensor connector terminal 2 and ground.
- The ohmmeter should indicate 0.4 - 0.8K ohms.

If reading is OK:
^ Proceed to Checking Signal Cable section below.

If value is lower:
^ Check cable between throttle position (TP) sensor terminal 2 and engine control module (ECM) # A15 for a short-circuit to ground.
^ Then proceed to Verification section below.

If value is higher:
^ Proceed to test step below.





Checking The Engine Control Module Connector
- Ignition off.
- Throttle position sensor disconnected.
- Check engine control module connector for contact resistance and oxidation.
- Engine control module connected.
- Ignition on.
- Connect a voltmeter between throttle position sensor connector terminal 2 and ground.
- The voltmeter should read approx. 5 Volts.

If reading is OK:
^ The diagnostic trouble code (DTC) was caused by poor contact in the engine control module connector.

If reading is incorrect:
^ Check cable between throttle position sensor terminal 2 and engine control module # A15 for an open-circuit.
^ Then proceed to Verification section below.





Checking Signal Cable
- Ignition on.
- Throttle position sensor disconnected.
- Connect a voltmeter between throttle position sensor connector terminal 3 and ground.
- The voltmeter should read approx. 5 Volts.

If reading is OK:
^ Proceed to test step below.

If reading is incorrect:
^ Check cable between throttle position sensor terminal 3 and control module # A16 for a short-circuit to ground.
^ Then proceed to Verification section below.





Checking Throttle Position Sensor Signal
- Ignition off.
- Connect the throttle position sensor.
- Start engine
- Go into diagnostic trouble code parameter list.
- Read off throttle angle.
- The throttle angle should be when the engine is idling and should increase as the accelerator pedal (AP) is depressed.

If reading is OK:
^ The diagnostic trouble code has been caused by poor contact in the throttle position sensor connector. Check connector for contact resistance and oxidation.
^ Then proceed to Verification section below.

If reading is incorrect:
^ Try a new throttle position sensor.
^ Then proceed to Verification section below.





Verification
- After carrying out the repair, check that the fault has been remedied as follows.
- Ignition off.
- Throttle position sensor and engine control module connected.
- Ignition on.
- Go into scrolling values list.
- Read off the throttle position sensor value.
- At closed throttle position (CTP) voltage should exceed 0.1 Volts, at wide open throttle (WOT) voltage should be below 4.9 Volts.

If reading is OK:
^ Fault corrected

If reading is incorrect:
^ Proceed to test step below.

Fault-tracing Information
The verification result shows that the fault persists.

- Do you want to exit fault-tracing?

Yes:
^ Fault not corrected

No:
^ Return to Checking Power Cable section above.