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Home >> Volvo >> 1998 >> S90 L6-2.9L VIN 96 B6304S >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> EFI / DTC Codes (Engine Control System) >> DTC EFI-355 >> Faulty Signal

Faulty Signal





Checking Throttle Position Sensor
- Ignition ON.
- Select Volvo Scan Tool (ST) to read off the value of the throttle position (TP) sensor.
- 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: Checking Throttle Position Sensor Signal section below.

If reading is incorrect:
^ Proceed to: Checking Connector section below.





Checking Throttle Position Sensor Signal
- Ignition ON.
- Select Volvo Scan Tool to read off the value of the throttle position sensor signal while the throttle slowly opens from closed to wide open.
- The signal should follow throttle position and should not have any interference.

If reading is OK:
^ Proceed to: Checking for Air Leakage in the Intake System section below.

If reading is incorrect:
^ Proceed to: Replacing Component section below.





Replacing Component
- Try a new throttle position sensor.
- Proceed to: Verification section below.





Checking Connector
- Ignition OFF.
- Check throttle position sensor and/or engine control module (ECM) connectors for contact resistance and oxidation and remedy.
- Connect throttle position sensor and/or the engine control module.
- Ignition ON.
- Select Volvo Scan Tool to read off the value of the throttle position sensor.
- At closed throttle position voltage should be between 0.2 - 0.6 Volts.
- At wide open throttle voltage should be between 3.8 - 4.6 Volts.

If reading is OK:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.

If reading is incorrect:
^ Proceed to: Checking Ground Lead section below.

Checking for Contact Resistance and Oxidation
- The cause of the diagnostic trouble code (DTC) has been loose connections in the throttle position sensor and/or the engine control module connectors.
- Proceed to: Verification section below.





Checking Ground Lead
- Ignition OFF.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Disconnect throttle position sensor.

NOTE: If the engine cooling fan runs on, it must be allowed to stop before taking resistance readings.

- Connect an ohmmeter between throttle position sensor connector terminal 1 and ground.
- The ohmmeter should read approximately 0 ohms.

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

If reading is incorrect:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.





Checking for Contact Resistance and Oxidation
- Check cable between throttle position sensor terminal and engine control module # A18 for contact resistance and oxidation.
- Proceed to: Verification section below.





Checking the Signal Cable
- Ignition ON.
- Throttle position sensor disconnected. Connect a voltmeter between throttle position sensor connector terminal 3 and ground.
- The voltmeter should read approximately 5 - 6 Volts.

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

If reading is incorrect:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.





Checking for Contact Resistance and Oxidation
- Check cable between throttle position sensor terminal 3 and engine control module # A16 for contact resistance and oxidation.
- Proceed to: Verification section below.





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

NOTE: If the engine cooling fan runs on, it must be allowed to stop before taking resistance readings.

- Connect an ohmmeter between throttle position sensor connector terminal 2 and ground.
- The ohmmeter should read approximately 0.4 - 0.8 k ohms.

If reading is OK:
^ Proceed to: Replacing Component section below.

If reading is incorrect:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.





Replacing Component
- Try a new throttle position sensor.
- Proceed to: Verification section below.





Checking for Contact Resistance and Oxidation
- Check cable between throttle position sensor terminal 2 and engine control module # A15 for contact resistance and oxidation.
- 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?

Yes:
^ Proceed to: Verification section below.

No:
^ Proceed to: Checking Power Ground section below.





Checking Power Ground
- Ignition OFF.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Disconnect mass air flow sensor.
- Connect an ohmmeter between mass air flow sensor connector terminal 1 and ground.
- The ohmmeter should read approximately 0 ohms.

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

If reading is incorrect:
^ Proceed to: Checking Control Module Connector section below.





Checking Control Module Connector
- Ignition OFF.
- Mass air flow sensor disconnected.
- Check control module connector for contact resistance and oxidation and remedy.
- Control module connected.
- Connect an ohmmeter between mass air flow sensor connector terminal 1 and ground.
- The ohmmeter should read approximately 0 ohms.

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

If reading is incorrect:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.





Checking for Contact Resistance and Oxidation
- Check cable between mass air flow sensor terminal 1 and engine control module # A3 for contact resistance and oxidation.
- Proceed to: Verification section below.





Checking Signal Ground
- Ignition OFF.
- Mass air flow sensor disconnected.
- Connect an ohmmeter between mass air flow sensor connector terminal 2 and ground.
- The ohmmeter should read approximately 0 ohms.

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

If reading is incorrect:
^ Proceed to: Checking Control Module Connector section below.





Checking Control Module Connector
- Ignition OFF.
- Mass air flow sensor disconnected.
- Check control module connector for contact resistance and oxidation and remedy.
- Control module connected.
- Connect an ohmmeter between mass air flow sensor connector terminal 2 and ground.
- The ohmmeter should read approximately 0 ohms.

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

If reading is incorrect:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.





Checking for Contact Resistance and Oxidation
- Check cable between mass air flow sensor terminal 2 and engine control module # A5 for contact resistance and oxidation.
- Proceed to: Verification section below.





Checking Power Cable
- Ignition OFF.
- Disconnect mass air flow sensor.
- Ignition on.
- Connect a voltmeter between mass air flow sensor connector terminal 3 and ground.
- The voltmeter should read battery voltage.

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

If reading is incorrect:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.





Checking for Contact Resistance and Oxidation
- Check cable between mass air flow sensor terminal 3 and main relay (2/32) terminal 3 for contact resistance and oxidation.
- Proceed to: Verification section below.





Checking the Signal Cable
- Ignition ON.
- Mass air flow sensor disconnected.
- Connect a voltmeter between mass air flow sensor connector terminal 4 and ground.
- The voltmeter should read 0 - 1 Volts.

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

If reading is incorrect:
^ Proceed to: Checking for Contact Resistance and Oxidation section below.





Checking for Contact Resistance and Oxidation
- Check cable between mass air flow sensor terminal 4 and engine control module # A4 for contact resistance and oxidation.
- Proceed to: Verification section below.





Checking the Signal Cable
- Ignition OFF.
- Connect mass airflow sensor.
- Connect breakout box.
- Connect control module.
- Connect a voltmeter between terminals # 5 (A5) and # 4 (A4).
- Ignition ON.
- The voltmeter should read 0.1 - 0.2 V.

If reading is OK:
^ Proceed to: Fault-tracing Information section below.

If reading is incorrect:
^ Proceed to: Replacing Component section below.

Fault-tracing Information
- The cause of the diagnostic trouble code has been loose connections in the mass air flow sensor and/or engine control module connectors.
- Check connectors for contact resistance and oxidation and remedy.
- Proceed to: Verification section below.





Replacing Component
- Try a new mass air flow sensor.
- Proceed to: Verification section below.





Verification
After carrying out the repair, check that the fault has been remedied as follows:

- Reconnect connectors and reinstall components.
- Disconnect the Volvo Scan Tool from the VIDA station and use it in stand-alone mode.
- Erase diagnostic trouble codes.
- Go into the Diagnostic Test Mode (DTM) menu.
- Test drive the car.
- Run the engine to operating temperature (above 80°C (+176°F)).
- Watch EFI-355, wait until the status of EFI-355 switches to tested.
- Read off diagnostic trouble codes.
- EFI-355 should not be stored.

If reading is OK:
^ Fault corrected.

If reading is incorrect:
^ Fault not found.
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