2007 4.2L FSI w/ rough idle P0102 P010C Low MAF

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stone4779

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My girlfriend and I just purchased a 2007 Audi Q7 4.2L Quattro. She has wanted an Audi since forever...and we made it happen..albeit it does have some issuea..but me being very mechanically inclined, and somewhat familiar with electronics...I/we thought it was a worthwise purchase. I've been in wanting to have a reason to buy a cable and software for these for a while, and enjoy learning how to work on different things. I am extremely familiar with General Motors products mechanically and electrically, I don't think I've ever had a problem I was not ultimately able to fix on those. Anyways with that being said, from what I've learned so far it's going to be a fun learning experience figuring out the electronics on these.
Anyways, the main thing that I would like to address first, is that it has a extremely rough idle, and when you get really into the accelerator pedal, the engine falls flat on its face. I have a generic scanner that I use often, I was able to generate a scan report. Attached is a link to the scan report

https://drive.google.com/file/d/1h7T...w?usp=drivesdk

So far I have found out that both mass air flow sensors are either sending a low signal or no signal. I'm thinking the first thing I need to do is get the cable/software so that I can properly log the output on the various Electronics. The scanner that I have is showing 0 volts on the mass airflow sensor and other things that should not be zero. Also on my generic scanner the RPM shows 0 which is odd. The tachometer on the vehicle does not display zero, it works.

Originally I had some misfire codes for cylinder number 1 and cylinder number 8. I have replaced the ignition coil packs on those cylinder and the codes have not returned since.

When on the freeway and using light to medium throttle pedal action, the vehicle run smoothly and strongly. You wouldn't notice anything on the freeway unless you needed to pass someone quickly.

I have checked the connectors and the wiring but have not ruled out shorted circuit or wiring and have not ruled out broken wires.

Thanks for the help. I'm going to continue reading other threads using the search function. Sorry if there are grammatical errors or improper sentence structures. I'm using speech to text on my phone
 
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stone4779

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Heres a list of the current DTC codes set ...for those that prefer not to click links etc:

11 Confirmed Trouble Codes:
• P0458: EVAP System Purge Control Valve "A" Circuit Low
• P2257: AIR System Control "A" Circuit Low
• P2295: Fuel Pressure Regulator 2 Control Circuit Low
• P129C: Fuel Pressure Regulator Valve -N276, Bank 2 Short circuit to Ground (GND).
• P0102: Mass or Volume Air Flow Sensor "A" Circuit Low
• P010C: Mass or Volume Air Flow Sensor "B" Circuit Low
• P0031: HO2S Heater Control Circuit Low Bank 1 Sensor 1
• P0051: HO2S Heater Control Circuit Low Bank 2 Sensor 1
• P2401: EVAP System Leak Detection Pump Control Circuit Low
• P0057: HO2S Heater Control Circuit Low Bank 2 Sensor 2
• P0036: HO2S Heater Control Circuit Bank 1 Sensor 2

11 Pending Trouble Codes:
• P0458: EVAP System Purge Control Valve "A" Circuit Low
• P2257: AIR System Control "A" Circuit Low
• P2295: Fuel Pressure Regulator 2 Control Circuit Low
• P129C: Fuel Pressure Regulator Valve -N276, Bank 2 Short circuit to Ground (GND).
• P0102: Mass or Volume Air Flow Sensor "A" Circuit Low
• P010C: Mass or Volume Air Flow Sensor "B" Circuit Low
• P0031: HO2S Heater Control Circuit Low Bank 1 Sensor 1
• P0051: HO2S Heater Control Circuit Low Bank 2 Sensor 1
• P2401: EVAP System Leak Detection Pump Control Circuit Low
• P0057: HO2S Heater Control Circuit Low Bank 2 Sensor 2
• P0037: HO2S Heater Control Circuit Low Bank 1 Sensor 2

2 Air Conditioning Trouble Codes:
• P0638: Engine/Transmission Electrical Connection 2. Also check for loose ECM powerrelay. (1592)
• P09CC: Check report for description. (2508)

1 Battery Energy Control Module Trouble Codes:
• P0513: Immobilizer Incorrect Key (1299)

2 Brakes Trouble Codes:
• P0522: Engine Coolant Temp. Sensor (G62): Break in wiring / short circuit to positive (1314)
• P01C9: Fuel Rail/System Pressure Bank 2 Too High (457)

2 Central Module Comfort System Trouble Codes:
• P05DF: Brake Pedal Position Sensor "B" Circuit Intermittent/Erratic (1503)
• P046E: Exhaust Gas Recirculation Sensor "B" Circuit Range/Performance (1134)

11 Engine Control Module Trouble Codes:
• P0458: Evap System Purge Control Valve (N80): Short to Ground (1112)
• P1435: Secondary Air Pump Relay (J299): Short to Ground (5173)
• P2295: Fuel Pressure Regulator "B" Control Circuit Low (8853)
• P129C: Fuel pressure regulator valve bank 2 Short circuit to ground (4764)
• P0102: Mass Air Flow Sensor (MAF/G70): Signal too Low (258)
• P010C: Mass or Volume Air Flow Sensor "B" Circuit Low (268)
• P0031: O2 Sensor Heater Contr. Circ.(Bank1(1)Sensor 1) Low (49)
• P0051: O2 Sensor Heater Contr. Circ.(Bank2 Sensor 1) Low (81)
• P2401: Evaporative Emission System Leak Detection Pump Control Circuit Low (9217)
• P0057: O2 Sensor Heater Contr. Circ.(Bank2 Sensor 2) Low (87)
• P0037: O2 Sensor Heater Contr. Circ.(Bank1(1)Sensor 2) Low (55)

1 Lane Change Assistant Trouble Codes:
• P3FED: Check report for description. (16365)

1 Tire Pressure Monitoring Trouble Codes:
• P08A6: Gear Lever Position Sensor System - Multiple Sensor Correlation (2214)

1 Transmission Control Module Trouble Codes:
• P0522: Engine Coolant Temp. Sensor (G62): Break in wiring / short circuit to positive (1314)

The random misfire code and the misfire code for cylinder number 1 & 8 have since returned also. I'm about to go into work for a little while so I'm just copying and pasting all this from another forum. Haven't been able to get any help over there but it's only been one day so
 
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I saw a thread where similar codes were thrown for short to ground, and one of them was p2295 for the high pressure fuel pump on bank 2 (n275) as well.. it took him a year to figure it out but ultimately it was the bank 2 high pressure fuel pump n275 had failed mechanically and electrically , and was shorting out everything (02 sensors...hpfp, maf sensors x2, evap leak detection, evap system purge, secondary air pump, etc..)

So that gave me the idea of unplugging all the sensors that were throwing codes individually one by one, and then resetting the codes with the scanner, and then starting the car again, and then rescanning the car for codes to see if anything had changed, to see if everything was still shorting out.

So far I have unplugged both of the mass airflow sensors individually, both of the high pressure fuel pumps individually, the coolant sensor on the coolant overflow tank, and what i believe to be the evap purge valve. I have not unplugged the coolant sensor on the upper radiator hose on the drivers side of the engine bay/radiator. Also unplug some sort of sensor on what appears to be either the EGR or evap canister. I'm going to try to attach a picture of the two things i disconnect which i am not 100% sure which item they are
 
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Also..I hear a ticking sound at the top of the intake manifold, at the front of the engine, at the intake runner control valve in the top middle. Engine OFF key OFF. (?) Wierd. Like its buzzing from being shorted. But no DTC for it. Weird.

There wasnt a DTC set for the intake manifold runner control valve..but I figured I would check it too. Since i heard that. No luck there either...

https://drive.google.com/file/d/1IeCzeE8oFYPBIYj0Qyht1KYpTGMsQh43/view?usp=drivesdk
 
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stone4779

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My next check is to unplug the 02 sensors ..all of them..to see if the MAFs are still shorted or low signal... If it changes and isnt shorted..then I can try and pinpoint if al or some or just one 02 sensor is bad/shorted out.

Would a VCDS HEX-V2 Enthusiast USB Interface be sufficient to diagnose and repair something like this?

I wish I coukd just buy it right now but not yet...but soon :)
 
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stone4779

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Okay so I'm going to be focusing on the codes involving shorts to ground.

Does anyone know the coolant temperature sensor location? The one called G62?

Maybe I can tackle that 1 first and see if theres an obvious short somewhere.

Makes it kind of difficult cuz I only have about one hour per day to mess with it but I'm going to keep at it! :-)
 
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Jack@European_Parts

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Given his question, "Would a VCDS HEX-V2 Enthusiast USB Interface be sufficient to diagnose and repair something like this?" I gather he does not have VCDS at this time.

-Uwe-


See that OP /\ so maybe you need this link.....?

I recommend all the bells and whistles myself two thumbs up......... :p

https://store.ross-tech.com/shop/cat/VCDS

good-bad-thumbs-3
 
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stone4779

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Hello OP and welcome to the VCDS forum.

Please get verified and post a complete auto-scan with a complete JPPSG

It will help us help you....... you have a ton of faults and posts.

I would recommend you get a RTFB to search components or perform tests.


http://wiki.ross-tech.com/wiki/index.php/Official_Factory_Repair_Information


https://forums.ross-tech.com/showth...essional-Problem-Solver-Guide-quot-JPPSG-quot



Thanks for the reply :)

OK after I get out of work today I will get a 1 day Erwin subscription and print everything on my vehicle to PDF, and then I will check all fuses and relays. I have a little experience checking continuity and resistance using a Digital Multimeter...you're right I should check all the basics first! I need to get the proper Torx bit to flip the driver's seat back to check everything under there. I had a T55 which was too big, so today I will also get the proper size Torx bit socket to remove the driver's seat.

Get verified? D0nt I have to have VCDS for that?

As far as VCDS..I do not have it yet. I wish that I did, but right now I cannot afford it...hopefully later on this week I can order VCDS and a cable from Ross-tech! Cant wait to play with it lol. This generic scanner is a hit or miss on imports.

THanks again for the reply

I was wondering where I could get access to the wiring diagrams, searched a lot but found limited info. The Erwin thing costs money, but has valuable info I am sure. :) Cant wait to get out of work and print those diagrams to PDF.

I will update after I have identified and checked all the appropriate fuses and relays I can think of. Already checked the ones under the hood near the cowl on the driver's side of the engine bay.
 
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Jack@European_Parts

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Thanks for the reply :)

OK after I get out of work today I will get a 1 day Erwin subscription and print everything on my vehicle to PDF, and then I will check all fuses and relays. I have a little experience checking continuity and resistance using a Digital Multimeter...you're right I should check all the basics first! I need to get the proper Torx bit to flip the driver's seat back to check everything under there. I had a T55 which was too big, so today I will also get the proper size Torx bit socket to remove the driver's seat.

Get verified? D0nt I have to have VCDS for that?

As far as VCDS..I do not have it yet. I wish that I did, but right now I cannot afford it...hopefully later on this week I can order VCDS and a cable from Ross-tech! Cant wait to play with it lol. This generic scanner is a hit or miss on imports.

THanks again for the reply

I was wondering where I could get access to the wiring diagrams, searched a lot but found limited info. The Erwin thing costs money, but has valuable info I am sure. :) Cant wait to get out of work and print those diagrams to PDF.

I will update after I have identified and checked all the appropriate fuses and relays I can think of. Already checked the ones under the hood near the cowl on the driver's side of the engine bay.




Great when you get your unit and post your scan I look forward to trying to help as well as the rest of the collective.

Post your VIN so I can do a config pull for you, it helps you when looking up repair information or options explained a bit.
 
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stone4779

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Great when you get your unit and post your scan I look forward to trying to help as well as the rest of the collective.

Post your VIN so I can do a config pull for you, it helps you when looking up repair information or options explained a bit.

Thanks Jack I appreciate it. And everyone. I've always found online forums to be valuable resources when trying to diagnose problems.

By the way, the VIN number for the vehicle is WA1AV74L17D02612.

I get out of work in 2 hours, I look forward to checking everything underneath the driver seat! :-)
 
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stone4779

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OK guys...update...

I found that fuse #13 on the fuse box under the cowl on driver's side of engine bay was blown!

I dont know how I missed it before, as I had checked every one the fuses there many times. At first glance it looks good, but if you look verrry closely, you can tell that it is blown. I replaced it and it blew again immediately.

I noticed all this stuff ran off that fuse, which drew my attention specifically to it first:

Air mass meter -G70-1)
Air mass meter 2 -G246-1)
Activated charcoal filter solenoid valve 1 -N80-1) 2)
Secondary air inlet valve -N112-1) 3)
Fuel metering valve -N290-1) 2)
Intake manifold flap valve -N316-2) 3)
Secondary air inlet valve 2 -N320-1) 3)
Fuel metering valve 2 -N402-1)
Oil pressure control valve -N428-3)
Continued coolant circulation pump -V51-3)
Fuel system diagnostic pump -V144-1) 2) 3)
Crankcase breather system shut-off valve -N548-3) only

So to go back to the idea I had found before in another thread..I unplugged N276 (driver's side HPFR) and cleared all the codes. So far it has not blown again, and most of the codes have not immediately popped back up as they had before I found that blown fuse and replaced it.

The DTC codes that have returned immediately are:

(of course) P129B: Fuel Pressure Regulator Valve -N276, Bank 2 Open circuit

This is to be expected, as I unplugged the connector on N276..so it is at least picking up on the fact that it is now an open circuit.

and drumroll.....

P0513: Immobilizer Incorrect Key (1299)
P01C9: Fuel Rail/System Pressure Bank 2 Too High (457)
P1479: Brake Boost Vacuum System: Mechanical Failure (5241)
P08A6: Gear Lever Position Sensor System - Multiple Sensor Correlation (2214)

That it....I hadnt seen the P1479 before...which is very odd.

So either the MAFs and 02 heaters and AIR and EVAP stuff will take longer to set a DTC, or they arent coming back. We will see.

Previously, all those dozens of DTCs would immediately set right after clearing all DTCs with my generic scanner.

I am optimistic.

on a side note, upon turning the key forward, or starting the car, the MMI screen used to come on for a couple seconds, maybe 15-20, and then turn off. It would repeat this a couple more times and then not come back on until I drove the car again. Sometimes while driving the MMI screen would randomly being this sequence again and then go blank for the rest of the trip.

Previously the volume and source buttons wouldnt work on the steering wheel, now they do. Now sometimes the screen stays on the hwole time I am driving....BUT the whole stack of buttons in front of the armrest do not work. I cannot navigate menus and stuff.. MMI is stuck at the phone screen. Telling me I do not have a phone connected etc. So no music.

Sometimes it stays onf or good..sometimes not.

I am not really that focused on the MMI right now though...I need the surging at low speed and stops and near-stops to go away. The idle is much much better now...It still falls on it's face when you try and go wide open throttle or anything past like 50% throttle. It feels strong up until then. Like driving around even getting into the throttle a little bit to pass people it feels fine...but as soon as you want more than just "passing" power...it falls flat on its face. :(

The auto parts store didnt have an M10 XZN socket I need to remove the driver's seat to access things, I can get that later.
 
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Fuse # 13 below is the one that blew taking out the MAFs and stuff with it...



and just to clarify..this fuse powers the following items according to my fuse box diagram:

Air mass meter -G70-1)
Air mass meter 2 -G246-1)
Activated charcoal filter solenoid valve 1 -N80-1) 2)
Secondary air inlet valve -N112-1) 3)
Fuel metering valve -N290-1) 2)
Intake manifold flap valve -N316-2) 3)
Secondary air inlet valve 2 -N320-1) 3)
Fuel metering valve 2 -N402-1)
Oil pressure control valve -N428-3)
Continued coolant circulation pump -V51-3)
Fuel system diagnostic pump -V144-1) 2) 3)
Crankcase breather system shut-off valve -N548-3) only
 
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I am the last thing from an expert, but if you are having all those weird issues engine issues along with the radio/mmi/steering wheel that seems to be a pretty apparent wiring issues.

With all those different systems, my first thought would be that the vehicle has been through a flood and has internal wiring damage or corruption.

my second thought would be water damage/leakage from under windshield/cowl area, just based on affecting interior and engine systems.

I don't know anything about this model or whether there are any known water leakage/damage areas to look at, but that might be a good place to start.

but I'll repeat I would not even qualify as a shade tree mechanic at this point, so take all that with lots of salt.
 
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stone4779

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I am the last thing from an expert, but if you are having all those weird issues engine issues along with the radio/mmi/steering wheel that seems to be a pretty apparent wiring issues.

With all those different systems, my first thought would be that the vehicle has been through a flood and has internal wiring damage or corruption.

my second thought would be water damage/leakage from under windshield/cowl area, just based on affecting interior and engine systems.

I don't know anything about this model or whether there are any known water leakage/damage areas to look at, but that might be a good place to start.

but I'll repeat I would not even qualify as a shade tree mechanic at this point, so take all that with lots of salt.

I think that you may be right. I took the MMI controls out and took them apart, and the insides had dried coffee and/or soda inside everywhere...I tried cleaning everything with alcohol and cotton swabs/q-tips. The MMI screen comes on now and stays on most of the time. I am able to use none of the MMI controls though..they still do not work.

We ordered a brand new circuit board for the MMI controls which gets here Saturday hopefully. I suspect that has a good chance of fixing the MMI controls.

and yes I have checked the fuse boxes and the amplifier and the spare tire well..all the known places for water to cause problems...I have seen no signs of water intrusion into anything so far.

Still unable to purchase the Hex V2 Enthusiast quite yet...but soon we will. Hopefully by the end of the month.

I did replace the G62 coolant temp sensor which is at the back of the engine, in the coolant crossover tube that runs from one cylinder head to the other. Under the throttle body.

It was/is throwing a P0522 code which indicates a short to ground on that sensor (G62). Replaced it and cleared the codes. The P0522 still returns after a while. So I guess that didnt cure that problem.
 
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