Faulty Signal
FAULTY SIGNAL
Checking the Throttle Position Sensor
- Ignition ON.
- Go into scrolling values list.
- Read off the Throttle Position (TP) Sensor value.
At Closed Throttle Position (CTP) voltage should be between 0.2 - 0.6 Volts.
At Wide Open Throttle (WOT) voltage should be between 3.8 - 4.6 Volts.
If reading is OK:
- Proceed to test step below.
If reading is incorrect:
- Proceed to Checking the Connector section below.
Checking Throttle Position Sensor Signal
- Ignition ON.
- Go into scrolling values list.
- Note the value while the throttle slowly opens from closed to wide open.
The signal should follow throttle position and should not have any intenference.
If reading is OK:
- Proceed to Checking for Air Leakage in the Intake System section below.
If reading is incorrect:
- Try a new throttle position (TP) sensor.
- Then proceed to Verification section below.
Checking the Connector
- Ignition OFF.
- Check throttle position (TP) sensor and/or engine control module (ECM) connectors for contact resistance and oxidation and remedy.
- Connect throttle position (TP) sensor and/or the engine control module (ECM).
- Ignition ON.
- Go into scrolling values list.
- Read off the throttle position (TP) sensor value.
At closed throttle position (CTP) voltage should be between 0.2 - 0.6 Volts.
At wide open throttle (WOT) voltage should be between 3.8 - 4.6 Volts.
If reading is OK:
- The cause of the diagnostic trouble code (DTC) has been loose connections in the throttle position (TP) sensor and/or the engine control module (ECM) connectors.
- Proceed to Verification section below.
If reading is incorrect:
- Proceed to test step below.
Checking Ground Lead
- Ignition OFF.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Disconnect throttle position (TP) 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 (TP) sensor connector terminal 1 and ground.
The ohmmeter should read approx. 0 Ohms.
If reading is OK:
- Proceed to test step below.
If reading is incorrect:
- Check cable between throttle position (TP) sensor terminal 1 and engine control module (ECM) #A18 for contact resistance and oxidation.
- After remedying fault proceed to Verification section below..
Checking Signal Cable
- Ignition ON.
- Throttle position (TP) sensor disconnected.
- Connect a voltmeter between throttle position (TP) 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 (TP) sensor terminal 3 and engine control module (ECM) #A16 for contact resistance and oxidation.
- Then proceed to Verification section below.
Checking Power Cable
- Ignition OFF.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Disconnect throttle position (TP) 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 (TP) sensor connector terminal 2 and ground.
The ohmmeter should read approx. 0.4 - 0.8K Ohms.
If reading is OK:
- Try a new throttle position (TP) sensor.
- Then proceed to Verification section below.
If reading is incorrect:
- Check cable between throttle position (TP) sensor terminal 2 and engine control module (ECM) #A15 for contact resistance and oxidation.
- Then proceed to Verification section below.
Checking for Air Leakage in the Intake System
- Check for air leakage in the intake system.
Is there a leak?
No:
- Proceed to test step below.
Yes:
- Remedy as necessary.
- Then proceed to test step below.
Checking Power Ground
- Ignition OFF.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Disconnect mass air flow (MAF) sensor.
- Connect an ohmmeter between mass air flow (MAF) sensor connector terminal 1 and ground.
The ohmmeter should read approx. 0 Ohms.
If reading is OK:
- Proceed to Checking Signal Ground section below.
If reading is incorrect:
- Proceed to test step below.
Checking Engine Control Module Connector
- Ignition OFF.
- Mass air flow (MAF) sensor disconnected.
- Check engine control module (ECM) connector for contact resistance and oxidation and remedy.
- Engine control module (ECM) connected.
- Connect an ohmmeter between mass air flow (MAF) sensor connector terminal 1 and ground.
The ohmmeter should read approx. 0 Ohms.
If reading is 0K:
- Proceed to test step below.
If reading is incorrect:
- Check cable between mass air flow (MAF) sensor terminal 1 and engine control module (ECM) #A3 for contact resistance and oxidation.
- Then proceed to Verification section below.
Checking Signal Ground
- Ignition OFF.
- Mass air flow (MAF) sensor disconnected.
- Connect an ohmmeter between mass air flow (MAF) sensor connector terminal 2 and ground.
The ohmmeter should read approx. 0 Ohms.
If reading is OK:
- Proceed to Checking Power Cable section.
If reading is incorrect:
- Proceed to test step below.
Checking Engine Control Module Connector
- Ignition OFF.
- Mass air flow (MAF) sensor disconnected.
- Check engine control module (ECM) connector for contact resistance and oxidation and remedy.
- Engine control module (ECM) connected.
- Connect an ohmmeter between mass air flow (MAF) sensor connector terminal 2 and ground.
The ohmmeter should read approx. 0 Ohms.
If reading is OK:
- Proceed to test step below.
If reading is incorrect:
- Check cable between mass air flow (MAF) sensor terminal 2 and engine control module (ECM) #A5 for contact resistance and oxidation.
- Then proceed to Verification section below.
Checking Power Cable
- Ignition OFF.
- Disconnect mass air flow (MAF) sensor.
- Ignition ON.
- Connect a voltmeter between mass air flow (MAF) sensor connector terminal 3 and ground.
The voltmeter should read battery voltage.
If reading is OK:
- Proceed to test step below.
If reading is incorrect:
- Check cable between mass air flow (MAF) sensor terminal 3 and main relay (2/32) terminal 3 for contact resistance and oxidation.
- Then proceed to Verification section below.
Checking Signal Cable
- Ignition ON.
- Mass air flow (MAF) sensor disconnected.
- Connect a voltmeter between mass air flow (MAF) sensor connector terminal 4 and ground.
Voltmeter should read 0 - 1 Volts.
If reading is OK:
- Proceed to test step below.
If reading is incorrect:
- Check cable between mass air flow (MAF) sensor terminal 4 and engine control module (ECM) #A4 for contact resistance and oxidation.
- After remedying fault proceed to Verification section below..
Checking Signal Cable
- Ignition OFF.
- Connect the mass air flow (MAF) sensor.
- Connect the breakout box and check ground terminals.
- Connect transmission control module (TCM).
- Connect a voltmeter between terminals #5 (A5) and #4 (A4).
Voltmeter should read 0.1 - 0.2 Volts.
If reading is OK:
- The cause of the diagnostic trouble code (DTC) has been loose connections in the mass air flow (MAF) sensor and/or engine control module (ECM) connectors.
- Check connectors for contact resistance and oxidation and remedy.
- Then proceed to Verification section below..
If reading is incorrect:
- Try a new mass air flow (MAF) sensor.
- Then proceed to Verification section below.
Verification
Hint: After carrying out the repair, check that the fault has been remedied as follows.
- Reconnect connectors and reinstall components.
- ERASE DTC
- Run the engine to operating temperature (above 8O°C (176°F).
- Go into diagnostic test menu.
- Test drive the car
- Watch EFI-355, wait until the status of EFI-355 switches to tested.
- Read diagnostic trouble codes (DTCs).
EFI-355 should not be stored.
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 the Throttle Position Sensor section above.