Corrosion on the intake temperature sensor

A hot-film air-mass sensor made by Siemens is installed in the N53 6-cylinder petrol engine with direct fuel injection.

Intact hot-film air-mass sensor

The N53 is operated with stratified charge (lambda value up to 2.5) in wide operating ranges. This increases the air flow rate for this engine.

This increased air flow rate results in greater moisture in the air intake guide. Under difficult circumstances and with a saturated air-filter element, water and salt are deposited on the hot-film air-mass sensor.

The possible consequence is:

• Corrosion on the intake air temperature sensor that can lead to failure and causes a fault code memory entry.
  
  

Corroded intake air temperature sensor

If the connections on the intake air temperature sensor are corroded, the hot-film air-mass sensor must be replaced.

A fleece or improved air-filter element will be introduced to series production as a remedial measure in 09/2007; this prevents the problem from occurring.