Symptoms

Sudden power drop when it rains (mostly when driving in a column), or after driving through a puddle.

Cause – intake throttling due to damaged air filter

When driving fast on the road in the rain, jets of water driven by the vehicle in front may be sucked into the engine's intake system. In extreme cases, the filter element may become completely wet or swell. Through such a damaged filter, water reaches the air flow meter and causes an immediate change of the signals it sends. This is the cause of the power drop under the conditions described (the controller activates the failover program).

Troubleshooting and fault elimination

With some luck, the well-known text "implausible signal" from the mass air flow meter will be included in the fault memory. If a soaked air filter element is detected by visual examination, it is only exceptionally necessary to replace the flow meter. However, you also have to be careful when replacing the air filter: due to the large surface area, Original air filters should be fitted for thickness and high airflow rates, i.e.. from proven producers! Compared to cheap fakes, they are equipped with adequate reinforcements to prevent premature failure (symptoms of delamination) filter cartridge. Splashing water is very difficult to prevent, because the design of the intake system is imposed by the car manufacturer. You can only try to cover other air inlet openings in the area of ​​direct water inflow, e.g. seal the body holes and cable penetrations at the rear, that the direct suction of water from splashes is not possible.