Information on diagnostics

Air mass too high or too low

frequently this fault is not due to the air mass sensor

The engine check lamp lights up. Is this due to the air mass sensor? Is the air mass too high or too low? Or is the EGR valve stuck? You will find a list of possible reasons why the engine check lamp is lit here.

Suitable for

Product: air mass sensor

all vehicles provided with exhaust gas recirculation
and Pierburg air mass sensors

Pierburg No.
7.18221.51.0/.58.0; 7.22184.04.0 … .34.0/.50.0; 7.22684.07.0 … .10.0;
7.22701.04.0/.05.0; 7.28342.06.0/.07.0

 

POSSIBLE COMPLAINTS:

  • “P0102 air mass too low”
  • “P0103 air mass too high”

Whenever such error messages occur, a malfunction in the air mass sensor is often suspected. However, the malfunction can also be in the EGR system, for instance if the EGR valve is stuck
either when open or closed.

POTENTIAL FAULT:

a) The EGR valve (03) is permanently open

he amount of returned exhaust gas (07) is much higher than required. As a result, less fresh air (05) arrives at the cylinders. The air mass sensor measures less air than calculated by the engine control unit (06).

b) The EGR valve (03) remains closed

No or only very little exhaust gas is returned (07). As a result, more fresh air (05) arrives at the cylinders. The air mass sensor measures more air than calculated by the engine control unit (06).

REMEDY:

Check EGR valve and replace if necessary.


01 from the air filter
02 air mass sensor
03 EGR valve
04 to the catalytic converter
05 amount of fresh air
06 calculated air quantity
07 returned exhaust gas quantity
08 residual exhaust gas quantity (to the exhaust)

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