air flow sensor clip

[stevegbr]

had my engine management light come on this morning, only had the car a couple of months, it a c280 w204, the code is p0172 running rich on bank one, went to remove the air filter and noticed no spring clip at the back of the filter cover, so it lifted easy, question is can you buy the clip separate or do i after buy another air flow sensor. thanks.

 

[DSM10000]

had my engine management light come on this morning, only had the car a couple of months, it a c280 w204, the code is p0172 running rich on bank one, went to remove the air filter and noticed no spring clip at the back of the filter cover, so it lifted easy, question is can you buy the clip separate or do i after buy another air flow sensor. thanks.

Ask your local MB parts department regarding the clip.

If the clip is causing an air leak would it not be running lean? I would suggest getting the car to a Mercedes specialist for a proper scan with Star to rule out other problems.

From a quick search:

"This fault code is stored in the Engine Control Module (ECM) when the ECM is no longer capable of controlling the air-fuel ratio. For correct operation of the catalytic converter, the ECM is required to keep the air-fuel ratio (AFR) at approximately lambda 1, this equates to an AFR of 14.7:1 by mass. This is achieved by trimming the fuel mixture to the required amount to cater for slight anomalies during normal operating conditions. However, when a fault causes the fuel trim to exceed a predetermined level the malfunction indication light is illuminated and a limited operating strategy is employed. The pre-catalyst exhaust gas oxygen sensor is the primary component used for calculating the fuel trim once the system enters closed-loop control. The fuel trim data can be displayed as a percentage, either positive or negative. Under this condition, the fuel trim data will display a negative value. The ECM will decrease the injection duration to counteract the excessively rich mixture. This fault can be stored due to a faulty coolant temperature sensor, excessively high fuel pressure or a faulty fuel injector. The fuel trim is monitored under various loads and conditions. If a load or condition is included in the fault code this can be an advantage during diagnosis. Normally a code set during idle or light load is relating to an air leak. And a code set during high or part load can be a fuelling issue or an erroneous sensor signal."

Read more: P0172 Mercedes-benz - System Too Rich Bank 1