Help, TPMS, Traction Control, Fault Codes P0101, U1113

[pwdrskr]

Just had an issue with the allroad on the way to a BBQ. Car suddenly lost power briefly, TPMS and Traction Control warning lights come on. Car went into "limp" mode; low power.

Got to the BBQ and plugged in an APR dongle. Three codes:
P0101 Mass or Volume Air flow circle.
U1113 Function limitation due to received malfunction value
U1113 Function limitation due to received malfunction value
P2187 System too lean at idle, Bank 1

Last little note, car is due for service (already scheduled) so the "service now" message is showing in the DIS.

So what is this? Did some web searching and it seems it might be a faulty MAF Sensor. Is that it?

Can I drive it home safely (about 4 miles).

Thanks.

[blbroo]

Are you tuned? Aftermarket intercooler or hoses? Sounds like what happens when I blow a boost hose loose.

[pwdrskr]

Yes, tuned (K04). Checked all the hoses I could get to. All looked fine.

I actually had a hose pop off the inter cooler (turbo side) right after I had it installed. Systems then were way worse than this though similar.

[van462]

A quick test is to unplug the MAF sensor, tuck the plug away so it doesn't fall on the cat. Start the car it should idle correctly without a MAF. If driven the ECU will not allow the turbo to build boost but it may run smoother than if the MAF is sending it bad information. Shut down te car and plug in the MAF and see if the problems come back.

[pwdrskr]

A quick test is to unplug the MAF sensor, tuck the plug away so it doesn't fall on the cat. Start the car it should idle correctly without a MAF. If driven the ECU will not allow the turbo to build boost but it may run smoother than if the MAF is sending it bad information. Shut down te car and plug in the MAF and see if the problems come back.

I'll give that a try tomorrow.

Made it home with the car. Idled and drove fine, albeit with low power. Under load a whistling sound comes from the engine area. Makes me think turbo...

Tested for codes again after driving and got another one: P2187 System too lean at idle, Bank 1

Also, check engine light on in addition to TPMS and traction warning lights.

Along with the P0101 code this seems to be pointed at the MAF sensor crapping out.

My wife has a B8.5 A5. I'm going to grab the MAF sensor out of her car and see if that solves the problem tomorrow.

[van462]

PCV failure or a boost hose clamp loose are high suspects with whistle under boost. Under boost if the PCV fails it will eitehr vent out of the small hole on the PCV or pressurize the block and whistle out of the oil fill cap or where ever it can escape from.

[pwdrskr]

PCV was replaced recently. I'll give all the hoses and clamps a good look tomorrow.

Found a web page that seems to indicate one symptom may be whistling.

[pwdrskr]

UPDATE: well its not the MAF. Swapped with the wife's A5 and same issues. Put the allroad's MAF on the A5 and it's fine.

Inspected the hose between airbox and turbo for leaks and didn't find anything. Any other hoses I should check?

I did notice that the plug that attaches to the MAF doesn't "click" when its plugged in and the lock tab doesn't lock. It's been that way for some time if I'm not mistaken.

Tried clearing the codes several times and they come right back.

Looks like I'll be making an unscheduled stop into the dealership tomorrow morning.

[pwdrskr]

Are you tuned? Aftermarket intercooler or hoses? Sounds like what happens when I blow a boost hose loose.

Solved: you were right. I took the car to the dealership to sort it out and they found that the turbo outlet hose had blown off. I couldn't see it looking down from the engine bay. Had just put the car up and pulled the belly pan I'd have seen the hose and been able to reattach. So, had I not been lazy...

The trip to dealership wasn't a complete waste as they found that there is a transmission software update out for my car. Also was due for periodic maintenance (75K).

Lesson learned: don't be lazy and look at ALL hoses when this happens again.

[blbroo]

Great! Glad it was an easy, cheap fix.

That was the first hose I popped off after I installed the K04 and the most annoying one to get to.

[pwdrskr]

Great! Glad it was an easy, cheap fix.

That was the first hose I popped off after I installed the K04 and the most annoying one to get to.

Me too, Thx.

Moral of the story is don't be lazy and get under the car!