HOME

TECHNICAL BULLETINS

CORE ACCEPTANCE CRITERIA

SERVICE INFORMATION

COSHH/MSDS INFORMATION

KNOWLEDGE BASE

VIDEO LIBRARY

USER CONTRIBUTIONS

ASK THE EXPERTS

E-LEARNING  

TECHNICAL SUPPORT CONTACTS

PRIVACY POLICY










SPECIAL FEATURES

SIGN UP TO PART INFO

DOWNLOAD TECHNICAL LINKS

Log in   Sign up

Switches & Sensors

Air Mass Sensor

 
  • Determines air mass delivered to the engine which allows the ECU to adapt the fuel injection accordingly
  • Controls and monitors EGR flow rate in modern diesel applications

Troubleshooting

  • Symptoms:
    • Black smoke or soot appearing from the exhaust
    • Loss of power from the engine resulting in OBD light appearing
    • Car falling into ‘limp mode’
  • Possible causes for failure:
    • Sensor element has been destroyed by dust particles from the air supply system
    • Water contamination from a filter operating incorrectly
    • Engine oil coming into contact with sensor element

Testing:

Before inspecting the air mass sensor make sure the ignition is switched off as there will be electrical current running through the wiring.

  1. Once this is done disconnect the air mass sensor from its electrical connector. At this point start the engine and if the vehicle idle is better than before this shows that the sensor needs to be replaced.
  2. If this does not change the quality of idle, inspect the sensor element. If this appears to be contaminated with dirt or oil then the sensor will need replacing as this will be sending incorrect signals to the ECU.
  3. Check air filters and pipes for leaks as these can be the cause of the contaminant reaching the sensor. A clogged air filter may also restrict the airflow rate to the engine. If this is the case then these will also need replacing as well. Once replaced it is important that the code is erased. This will ensure that the new sensor can calibrate itself to the engine.
  4. Some vehicles may require ECU adaptation to ensure that the system recognises the new part. Please refer to specific vehicle manufacturer information.               

 

Other components to check:

  • EGR valve – a faulty EGR valve may cause an inconsistent flow rate from the throttle body
  • Lambda sensor – incorrect readings may cause the engine to increase airflow unnecessarily
  • Common Fault Codes

Common Fault Codes

 

  • P0100 Mass or Volume Airflow Circuit Malfunction
  • P0101 Mass or Volume Airflow Circuit Range / Performance Problem
  • P0102 Mass or Volume Airflow Circuit Low Input
  • P0103 Mass or Volume Airflow Circuit High Input
  • P0104 Mass or Volume Airflow Circuit Intermittent

Related Articles

Related Downloads