jamaza

Hi All,

I've had my engine light come on and after diagnostics it turns out to be a faulty MAF sensor. Today i've replaced it with new MAF sensors, but the engine light is still on and the car won't leave limp mode..

I've read up that disconnecting a battery will wipe the errors which will turn off the engine light and possibly my car will even leave the limp mode, so my question is:

1. Can I disconnect the battery on my car, and if so will this clear the errors?
2. Do I also have to disconnect the auxiliary battery, and just the main on is fine to wipe the errors?
3. Apart from wiping the errors, will this cause me issues apart from losing all user settings?

My car details:
Mercedes Benz 2011 E350 CDI

Your help is much appreciated guys!

Thanks!

kajtek1

Not sure battery disconnect will reset the code.
I replaced MAF on W210 and having no scanner - I cycled the ignition to start. Counted 7 starts in about 10 seconds till CEL went out
But the code will stay as historic one in car memory till you clear it.
It can get annoying when you buy used car and find 30 or 50 historic codes on it.

jamaza

Thanks for reply, I've just tried that but no luck.. I'll probably have to take it to my indie and get those errors cleared to see if it comes back.
I'm wondering about the limp mode, is this induced the error code sitting there so once cleared it will run normal again?

300SE1993

What code did you get? And no, the codes are written to memory so battery disconnect will not clear. There are 2 statuses to the codes, "Current" and "Stored". The only way to clear them is with a scanner that can read all the modules.

You need to have all the codes read, as the TCM (Transmission Control Module) has it's own set of codes. Is your ESP/BAS light on? If so, try replacing your brake light switch. Common failure that can trigger a limp mode along with ESP/BAS.

jamaza

Thanks for replies guys, so the codes i've got is listed on the attachment.

The mechanic suggested it's a MAF sensor, that's the root issue of all those errors, or atleast we should tackle that first...hence i've replaced it.

Video link showing my issue before MAF replacement, although it drives the same after it..

300SE1993

Unless I am missing something, it seems like it is shifting gears in your video. That's quite a collection of possibly random errors. Have you had your battery tested?

jamaza

It is shifting, but it only shifts after it revs to 3000 rpms, and i can have my foot down to the floor and it'll accelerate slowly..

No, but what could the battery be affecting so much that it'd put the car into limp mode?

300SE1993

Low battery voltage can cause chaos with the electronics.

Is your accelerator pedal harder than usual to push down? I was thinking brake light switch, but that usually throws ESP/BAS error too and you don't seem to have that.

Sunnyslope48

When you replacd the MAF sensor, did you replace with OEM or aftermarket? Remember that for any electrical device (MAF) to work correctly, it must have a correct and complete circuit to support the device. Good supply of the correct voltage, a good ground, and a good performance return to the ECM. All 3 are necessary. Lots of circuit problems listed. Could be rubbed thru wires.Could be a connector that is not making sufficient contact with the pins. In looking at the list of DTC's, I'd solve the MAF problems first, then see what remains.

kajtek1

The hand note is not showing if the condes are current, or historic.
You should have them cleared with MB-oriented scanner and then recheck.
Take picture of scanner screen to avoid confusion.