Lack of response

I have owned my 2007 Mercedes-benz E320 W211 CDI estate from new and it now has 106,000 miles. Recently, as I was accelerating away uphill from a roundabout, I experienced a loss of power similar to a stopped turbo. I could continue home afterwards, but at hugely reduced power. There were no engine lights showing and the only fault code stored was for the O2 sensor. Later that day, I tried a fast dual carriageway run and all was normal again. The codes showing were ‘P0130’ and ‘P0135’, both pending. Gareth Owen Both of these fault codes refer to the 02 sensors, specifically: ‘P0130 – Heated oxygen sensor (HO2S)/ oxygen sensor (O2S) 1, bank 1 - circuit malfunction’ and ‘P0135 – Heated oxygen sensor (HO2S) 1, bank 1, heater control – circuit malfunction’.

I am assuming that your Mercedes is fitted with an autobox. If this is correct, when the lack of power occurred was this because the gearbox did not change down, causing the engine to labour in too high a gear? The reason I mention this is that Autodata tells me there is a common transmission control module (TCM) software fault which can affect your vehicle and causes poor gearshift changes and does not leave fault codes.

If the gearbox is changing down as it should and the engine still has a lack of power, the problem may be related to the turbo, which could be jamming. With this in mind, it would be worth removing the induction pipe and carrying out a quick check of the impeller to ensure it’s spinning freely.