Dead MAF or something else? P1100 code

J

Jfgoldfish

Active member
Hi guys,
Me again! I've been chasing a rough idle issue that I initially though was either vanos solenoids or plugs/coils.
Cleaning the solenoids and replacing the plugs helped but didn't solve the issue.
The car finally threw a code today (p1100) which I believe points to the MAF sensor. Sure enough the value of the MAF sensor doesn't change at all when looking at the live data using a basic scan tool.
I am hoping someone can suggest my next move diagnosing the fault.
Does anyone know the pinout of the MAF connector so I can check it is getting power?
Can I check its output by back-probing the connector or will this not tell me much?
Should I just throw a new MAF at it and, if so, are the Bosch ones any good (that's what ECP seem to sell)?
Thanks all 😁👍
 
If you disconnect the Mafs electrical plug the car will default to default settings, check that and see if that improves the running.
If it runs better then Maf probably bad especially as your live data shows its not doing anything. You could try spraying it with Maf cleaner but that may not solve it. Oem part is preferable and Bosch or Seimens are oem,they aint cheap.
 
AFAIK the maf signal doesn’t show in a lot of the diagnostics... a few people have changed their maf unnecessary because of it.
 
Thanks for the advice guys. I will try disconnecting the MAF today and see what difference it makes.
It isn't a lack of reading but a steady 300ish g/m that the scan tool shows (could just be some sort of default value I suppose). I have read about other cases of no MAF readings from this particular engine so I am reluctant to throw parts at it.
I am still interested in what the P1100 code is telling me? If the sensor if ok what might the code be telling me?
 
Plugged in the reader today and the MAF is now showing readings perfectly and responding to throttle input.
I will need to check and clean the connector to make sure it isn't making intermittent contact.
Is it common for the sensor itself to fail intermittently or is it safe to say the sensor itself works at this point?
 
Could well be a connector problem as widely reported on the E46. Spray some wd40 / gt85 into the connector and plug it in and out a few times.
 
ph001 said:
Could well be a connector problem
Click to expand...

I suspect that is the case. I gave the contacts a gentle poke with a pick today to narrow them a tiny bit, cleaned them and applied some contact grease before plugging it back in.
So far so good. I assume the ecu will now be adapting to having its MAF properly connected so I will have to wait and see if the code reappears.

I like it when the solution is free!
 
A P1100 trouble code is stored when the Powertrain Control Module (PCM) detects a Mass Air Flow (MAF) sensor signal that falls above or below the manufacturer calibrated limits.

May well have been dodgy contacts in its plug and socket, time will tell, read the codes weekly to keep an eye on it, they do't always set a code or EML if going bad.
 
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