Function test instructions, air-mass sensor test M57

To ensure that the air mass system test provides a meaningful result, the test prerequisites listed below must be met without fail.

Preconditions for test

• The engine must be at operating temperature.
  
• All auxiliary loads such as rear window heating or air conditioning system, must be switched off.
  
• No electrical faults in the following systems may be stored in the DDE fault memory:
  
  • Charge-air-pressure control
    
  • Exhaust-gas recirculation
    
  • Air-mass flow sensor
    
  • Charge-air-pressure sensor
    
  • Intake Air Temperature Sensor
    
• Intake-air duct and exhaust system must be OK.