CLS 320 CDI 2009 MAF and IAT B2/7b and B2/6b error codes, MIL

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New Member
Nov 22, 2022
Mercedes CLS 320 CDI (C219) Stage 1 Remap
Hey there,

Bought CLS 320 CDI, stage 1 remapped, 2009 a couple of years ago and have this ongoing MAF mystery. Car drives fine, good power and torque, 40mpg on motorways, but the MIL can sometimes come on due to MAF sensors and Intake Air temperature error codes (same component). What I tried:

1. Clean MAF sensors.
2. Replace Air Filters
3. Replace breather pipe valve and all the seals around turbo...
4. Reset adaptation values in Star Xentry
5. Run tests in Star Xentry on both MAFs, Right and Left values fall within values range at Idle and with 1500rpm. Its measured in "us" not sure what is that but it was within range.
6. Took it to indy garage who do remaps and the guy said it was because EGR valve was leaking so he had it blocked and reset all the codes. The codes and MIL did not come up for a while I thought it was fixed. Untill I unplugged the battery during storage for long time, then when came back I had tons of codes with MAF codes again. Since then the same indy guy could not reset the codes and make them not appear....
7. Run Star Xentry tests on MAF again to check temperature values. The IAT did jump sometimes from 20 to 80 degrees C and then fall back down to 20/30ish, it seems odd so maybe the wiring needs checking? But can it really be both sensors? Do the share the same wire going to ECU?

Don't know what else, I think maybe the wiring needs checking because the temperature values do seem a bit odd sometimes too high to what it is... I have now reset the values again and the codes are not coming up after about 5 restarts but I am not holding my breath.

You need new air mass sensors. Only buy new from MB. Cleaning them never works btw.
Remove the map , go back to stock and see what happens .
Edit , just seen the experts comments above :cool: .

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