MAF sensor - supply voltage - wiring diagram

[vtraudt]

B7 A4 2.0T Quattro auto, BWT engine.

Trying to troubleshoot code:
000256 - Mass Air Flow Sensor (G70) P0100 - 004 - Supply Voltage

Changed MAF sensor, no difference.

Can some post the wiring diagram where the MAF sensor shows up?
I want to check the connector and then back trace.

Or other suggestions how to troubleshoot?

[aluthman]

Sounds like a wiring issue. Look for damage, particularly right next to the connector .

[EvolutionArmory]

You can go on erWin and create a day pass account and download complete wiring diagrams direct from Audi.

It will give the pin locations from the MAF to the ECU harness. You’re on the right track. You just need to know which pins to meter.

[vtraudt]

You can go on erWin and create a day pass account and download complete wiring diagrams direct from Audi.

It will give the pin locations from the MAF to the ECU harness. You’re on the right track. You just need to know which pins to meter.

Will give it try, thanks!

[vtraudt]

Sounds like a wiring issue. Look for damage, particularly right next to the connector .

Yes, that is what I suspect and the reason I try to find a wiring diagram for the MAF sensor.

Already inspected wiring as far as possible (but MAF pigtail goes into larger harness and disappears as usual).

3 pins car side connector with ignition on, pin to ground measurement:
Voltage: 5V, 0V, 12V
Resistance: 0 Ohm, open, 0 Ohm

[vtraudt]

You can go on erWin and create a day pass account and download complete wiring diagrams direct from Audi.

It will give the pin locations from the MAF to the ECU harness. You’re on the right track. You just need to know which pins to meter.

Signed up and paid. Turns out I bought VOLKSWAGEN erWin. Is there an AUDI erWIN? Only found out after trying numerous times to find ANY info on my Audi (including using the VIN).

[vtraudt]

Signed up and paid. Turns out I bought VOLKSWAGEN erWin. Is there an AUDI erWIN? Only found out after trying numerous times to find ANY info on my Audi (including using the VIN).

Paid again, got the AUdi pages now.

The 3 pins of the MAF sensor connector are:

Pin 1: ECM, 94 pin connector, pin 22, li lilac
Pin 2: square 110 (need to find), brown
Pin 3: to ECM, 94 connector, pin 87 (sw/li at ECM) AND to D100 (Plus connection 2 in engine compartment wiring harness), connector T17 (17 pin connector red, connector station E box, plenum chamber) to square 14

Tips where D100 and T17 are?

https://drive.google.com/open?id=1WtGnkh0wsUlJ8EYbg24vdQQWRScPsdwq

[EvolutionArmory]

So the ECU harness should be broken into 2 sections, right? Is one section the 94 pin section and the other the 17 pin section?

It’s been about 10 years since I’ve looked at an Audi wiring diagram.

So you should have 3 wires, right? Power, ground and signal. You just have to check those wires and see if they are are getting power and test the ground.

[vtraudt]

Yes, 2 ECU connectors, long and short one. That part is clear.
Not sure where the "E box" is. Might be the box with the multiple colored connectors (red, white, brown, black, beige, etc depending on car). This one has white, red, brown and ground bolt.
Could be this is the T17d (17 pin, red) and the T17j (17 pin, brown).

Found total of 4 broken (well, chewed through) wires. on was blue, the other 3 were yellow/green.

One green/yellow connects to the red plug, pin 1.
The blue goes to the white plug, pin 11.

Need to trace the other 2 yellow/green ones.

Is there a pin out for the 3 plugs to determine where they connect to the ECU?

Or an ECU pin out that shows the wires to the 3 plugs?

4 broken wires:
https://drive.google.com/open?id=1Q2C9tgD0-W2M8RhdPjsFO-y5SfabV7Ol

3 ECU box 17 pin connectors red, white, brown ("E box in plenum chamber"??):
https://drive.google.com/open?id=1V28GkO_pb9Kwsxg7Kv6boWP-iDYiBiAy

Blue wire on white connector, pin 11?:
https://drive.google.com/open?id=1HmFkcc22wNGvXV0mJ6BDS4ad0UH-GsZr

Yellow/Green wire on red connector, pin 1?
https://drive.google.com/open?id=1zyAPLcxyn_ANhjeI5I8r3C5Bz1iRdghS
https://drive.google.com/open?id=1KMDuAItJYIYBoyHSSbdeaBXDNalhCJLp

[EvolutionArmory]

I’m sorry I can’t be of more help. It’s been a very long time since I’ve had to get that into it with a wiring diagram. I’m going off of info I’ve mostly forgotten from 10 years ago😞

If you have actual broken wires in your engine harness, maybe your best course of action is to buy a used complete engine harness and just get all of that wiring out of there. Or depending on how savvy you are, and it appears you’re up to it, find the pin locations for those wires, depin them from the ECU harness and just make an overlay harness. You can buy pre pinned wire lengths from the dealer. You’ll just need the correct depin tool sizes.

Again, I’m sorry I can’t be more helpful. At least you have the erWin site to help you so at least I got you there.