Audi

Audi repair questions? Ask a mechanic for answers ASAP

Connect one-on-one with {0} who will answer your question

This answer was rated:

I have 1999 audi 2.4 testing the mass air flow sensor

I have 1999 audi...

I have 1999 audi 2.4 testing the mass air flow sensor harness and there is no constant voltage from ecu harness. the car do not start.

Mechanic's Assistant: Does the engine stall right after starting? And what about hesitation or jerking during acceleration?

The car do not start now, it was staying on very low idle, now nothing.

Mechanic's Assistant: What is the model of your '99 Audi?

A4 2.8

Mechanic's Assistant: Are you fixing your A4 yourself? What have you tried so far?

I've been a little troubleshooting, the car has been giving to me.

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

I have codes P1102, P1857, P1545. P1705,

Show More
Show Less
Ask Your Own Audi Question
Answered in 9 hours by:
3/1/2018
Audi Mechanic: Chris (aka - Moose), Technician replied 4 years ago
Chris (aka - Moose)
Category: Audi
Satisfied Customers: 77,641
Experience: 24 years of experience diagnosing & repairing
Verified

Welcome, I'm Chris (aka-Moose).

  • THE TIME I AM ONLINE, 7 days a week normally online around midday and then late evening until early morning.
  • PHONE CALLS are automatically offered by the website normally after my first reply. I complete calls where I feel it is a benefit.
  • UPLOADED LINKS I SEND, if I upload dropbox links, the will open on a home PC, often they fail on a work PC, on a phone use the box on the top right for direct download.

Have you worked through the diag steps for any of the codes you have?

Ask Your Own Audi Question
Customer reply replied 4 years ago
I even put a mass air flow sensor, fuel regulator, I think my problem became worse when I did'nt see the 5 volts from Emc. I was getting battery voltage, but not now I found no.29 fuse and 15amp no.34 blown.the car was hard start but eventually came on in very low idle then stall. I was told by the owner before me. He took to a mech and said one of problems was throttle aligment.(Adapt.I believe the main problem no voltage from 12v, 5v source from emc it has ground. Did continuity test from ground to constant wire got continuty(maybe spelling it wrong) ground to ground (continuity) The 5v wire nothing.
Audi Mechanic: Chris (aka - Moose), Technician replied 4 years ago

Have you confirmed all the computer powers an grounds are good?

Is the theft system off, not activated with the key on?

Ask Your Own Audi Question
Customer reply replied 4 years ago
All the computer power consist of what? I know the 12v, 5v to mass air flow sensor is not there. The anti - Theft system I do not believe is activatedWhat? car kind of spits a little when starting.
Audi Mechanic: Chris (aka - Moose), Technician replied 4 years ago

I just got called to go out and do a job. I will opt out so another can help you.

Ask Your Own Audi Question
Audi Mechanic: Mike Rodgers,
 replied 4 years ago
Mike Rodgers
Category: Audi
Satisfied Customers: 8
Experience: Master Technician at Volkswagen Southtowne
Verified

Reading through what you have tried already, I have a few questions. Does the vehicle currently crank and try to start? Have you checked the 5v signal directly at the ECM, not the connector for Mass air flow sensor?

Ask Your Own Audi Question
Customer reply replied 4 years ago
HI Yes it cranks and tries to start, no I have not test the voltage (5v) ECM. Would that consist of testing through the harness of the ECM, also what about the battery voltage supply wire (none)
Audi Mechanic: Mike Rodgers,
 replied 4 years ago

It would consist of "back probing" the wiring right at the ecm with the key on. This will help isolate the voltage problem. If there is voltage present at the ecm, but not the maf sensor, we most likely have a wiring issue. If there is 12v into the ecm and no 5v out, the ecm could be the issue, or a ground for the ecm. I know it's all packed in there, but carefully look at the 02 sensor wiring. I've seen that wiring melt, chewed through by rodents, or torn causing the 5v signal to short out and ruin the ecm. Send me the VIN and I can tell you what wires to check at the ECM if you would like.

Ask Your Own Audi Question
Customer reply replied 4 years ago
Ok. WAUED28D2XA231819.
Audi Mechanic: Mike Rodgers,
 replied 4 years ago

In looking at the wiring diagram I see a fuse for both the ecm, maf and brake light switch. It is fuse s231, position 31 on fuse panel. Should be a 15 amp fuse. Check that first, then using a DVOM you should have your 5v signal coming out of pin 12 at the ecm with the key on engine off and ecm still pligged in. It is a yellow wire. Please let me know what you have found. If this has not solved your issue there are some other things we can check.

Mike Rodgers
Category: Audi
Satisfied Customers: 8
Experience: Master Technician at Volkswagen Southtowne
Verified
Mike Rodgers and 87 other Audi Specialists are ready to help you
Ask your own question now
Customer reply replied 4 years ago
Ok. I'll check it when I did check fuses 15a was blown. I then since put another, I thought it was 34 engine timing according to owners manual. Right now where going through a storm. I'll let you know. Thanks!! God Bless!!
Customer reply replied 4 years ago
Hi" I Check the emc, might not a fitted the clip in the yellow wire ,there was voltage. but I did check a couple of other connections two on top of throttle body and I got about 5v. Check some other connection along firewall next to O2 sensors connection and there was nothing, right across from mass air flow sensor housing.
Audi Mechanic: Mike Rodgers,
 replied 4 years ago

Just to clarify, have you found the issue, or are you still in search of it? When you say the connectors on the firewall had nothing, how many pins are they?

Ask Your Own Audi Question
Customer reply replied 4 years ago
There is only one connector besides the mass air connector. are they on the same 5v curcuit.
Customer reply replied 4 years ago
HI' I didn't answer your question about the pins. One small connector 2pin it looks a 5v connector which I believe is in the mass air flow 5v. circuit. 3 or 4 connectors on top of throttle body reading 5v.
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with an audi mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Mike Rodgers Your Own Question
Mike Rodgers
Mike Rodgers
Mike Rodgers
Category: Audi
Satisfied Customers: 8
8 Satisfied Customers
Experience: Master Technician at Volkswagen Southtowne

Mike Rodgers is online now

Related Audi Questions
I have 1999 audi a4 2.8 quattro testing the mass air flow
hi' i have 1999 audi a4 2.8 quattro testing the mass air flow sensor with code P0103, P1857. found when i test ground of the mass air flow sensor ground at the connector, battery voltage was reading 1… read more
Wolfgang
Wolfgang
5,860 satisfied customers
Audi A4 Quattro: Hey Jake, I have a 1999 audi a4 2.8 quattro.
Hey Jake, I have a 1999 audi a4 2.8 quattro. The car will turn over, but will not crank ("fire"). The first time i went to start it cranked over very slowly but wont fire up fully. Now there is no fir… read more
vwtech0405
vwtech0405
VW Technician
Associate Degree
10,046 satisfied customers
Just picked up Audi A4 Quattro 2.8 had bad battery but would
Just picked up Audi A4 Quattro 2.8 had bad battery but would start with a jump box then I Replaced battery now won't start and has a p1545 code that normal scanner won't clear… read more
sprinkles08
sprinkles08
Technician
High School or GED
19,946 satisfied customers
Audi: Have a 99 audi A4 quattro 2.8 ATQ motor, I have replaced
Have a 99 audi A4 quattro 2.8 ATQ motor, I have replaced the following: coil pack plugs, wires, o2 sensors front and rear. Pcv valve, vacuum lines and still getting misfire codes, car runs great but n… read more
BOBBYSS
BOBBYSS
Automotive Repair/Damage Investigator
Associate Degree
14,739 satisfied customers
hi i hav 1999 audi a4 1.8t quattro i need to splice into ecu
hi i hav 1999 audi a4 1.8t quattro i need to splice into ecu harness into o2 sensor control wire i need to know which wire it is… read more
Marty
Marty
Vice President / Manager
Associate Degree
34,229 satisfied customers
Audi a4 2.8: On a 2000 Audi A4 2.8 quattro are there any basic
On a 2000 Audi A4 2.8 quattro are there any basic upgrades I can do to gain horsepower and/or better mpg. Are any of the following legitimate options or just hype? Continuous electric turbo 2.5 psi ht… read more
VWDoc
VWDoc
Owner
Bachelor's Degree
7,210 satisfied customers
2001 Audi Quattro: Crank Position..Fuel Pump Relay.. Fuse ok .
2001 Audi Quattro A4 1.8T L4 .. Has no spark.. Replaced Crank Position Sensor.. Replaced Hall Sender (Camshaft Position Sensor)...Replaced Fuel Pump Relay.. Fuse ok ..… read more
Roman Bihansky
Roman Bihansky
Master Technician
Associate Degree
850 satisfied customers
1998 audi a4: wagon..what road do i go down with that
1998 audi a4 wagon quat. 2.8. got a P1545 code. what road do i go down with that? Thanks Jack… read more
VWDoc
VWDoc
Owner
Bachelor's Degree
7,210 satisfied customers
Audi A4: quaTTRO..running fine..fine, the interior and exterior are
I'm about to buy an Audi A4 1999 2.8 quaTTRO with 170,000. The car seems to be running fine, the interior and exterior are immaculate.. I can get the car for $2,800. I've read a lot of review's that a… read more
VWDoc
VWDoc
Owner
Bachelor's Degree
7,210 satisfied customers
Audi a4: convertible..litre..voltage..reverse light stays on
i have a audi a4 convertible 2003 model 2.4 litre with a flappy paddle tiptronic gear box,had a problem with the gear box and replace the gear box with a used one and since we changed the gear box its… read more
jon-t
jon-t
Vocational, Technical or Trade Scho
895 satisfied customers
99 Audi a6 quattro: 2.8 engine will only run up to 1500 rpm
99 Audi a6 quattro 2.8 engine will only run up to 1500 rpm then it oscillates up and down. I can give you codes i've pulled .… read more
VWDoc
VWDoc
Owner
Bachelor's Degree
7,210 satisfied customers
1999 audi a4: battery died..jump started..rev..check engine light
i have a 1999 audi a4 2.8 liter v6 the battery died and i jump started it but now its not staying running b itself,the idle is pulsating and i have to rev it to keep it running do i just need to charg… read more
Michael Miller
Michael Miller
ASE Certified Technician
Vocational, Technical or Trade Scho
241 satisfied customers
1999 a4: misfiring..garage..reading with a scanner..abs light came on
My son in college had his audi 1999 a4 2.8 quattro completely failed (hard to start, and just plain unable to drive due to misfiring). He took it to a garage but they are unable to get a reading with … read more
Louis Gutierrez
Louis Gutierrez
AA in engineering technology
292 satisfied customers
hello got a 1999 audi a6 2.8l quattro station wagon, and it
hello got a 1999 audi a6 2.8l quattro station wagon, and it starts but it wont stay at idle. it dies and the codes im getting from the dtc plug are: 1- p1857 2- p1545… read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25,009 satisfied customers
1999 Audi A4: check engine light..programing..replacing..throttle body
Hello Have an 1999 Audi A4 2.8 Quattro with the check engine light on that will not take the throttle adaption programing. The tech said he checked the wires, connection and some other things and it s… read more
Michael Miller
Michael Miller
ASE Certified Technician
Vocational, Technical or Trade Scho
241 satisfied customers
1997 AUDI A4: O2 SENSOR..DRIVEN..FUEL PUMP..FUEL FILTER..COOLANT
1997 AUDI A4 1.6L MPI AHL REALLY STUCK ON THIS ONE REOCCURING CODE VAG 00537 O2 SENSOR UPPER STOP LIMIT ENGINE RUNS OK WHEN CODE CLEARED THEN WILL IDLE ALL DAY WITHOUT PUTTING ON CODE IF DRIVEN 2 MILE… read more
Wolfgang
Wolfgang
5,860 satisfied customers
2007 audi a4: gears..It also idles a bit rough..it misses..fuel filter
i have a 2007 audi a4 2.0 tdi..In the last 2 days as i drive along at a constant speed the car chugs a bit..It has plenty of power as i go through the gears..It also idles a bit rough at times as if i… read more
Louis Gutierrez
Louis Gutierrez
AA in engineering technology
292 satisfied customers
1999 Audi A4 Avant: V6..This problem came with the car
I purchased a 1999 Audi A4 Avant with the AHA 2.8 V6. This problem came with the car. Vehicle starts and idles fine after slight warm up. Engine seems to run on all 6 cylinders up to 1400 RPMs, at whi… read more
janoboy
janoboy
Bachelor's Degree
302 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible.

CharlesWalnut Creek, CA

As a single woman, I really appreciate an excellent and affordable opinion.
Thank you Geordie, I will not hesitate to contact justanswer in the future!

SueCharleston, WV

Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff.

JimCastleberry, FL

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

< Previous | Next >

Meet the Experts:

Matt

Matt

Engineer

632 satisfied customers

Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing

Chris (aka - Moose)

Chris (aka - Moose)

Technician

77,641 satisfied customers

24 years of experience diagnosing & repairing

Tim Mohr

Tim Mohr

ASE MASTER TECH

257 satisfied customers

30 YRS EXPERIENCE, FOREIGN AND DOMESTIC, GAS AND DEISEL

Michael Miller

Michael Miller

ASE Certified Technician

241 satisfied customers

ASE Master Technician. Audi certified, including R8 and TDI (clean diesel).

Quattro King

Quattro King

Technician

140 satisfied customers

ASE Master Certified, 20+ yrs European experience

mike

mike

ASE Certified Technician

115 satisfied customers

audi certified audi tech 4 years

Paul M ASE Master

Paul M ASE Master

ASE Master Tech

106 satisfied customers

ASE Master Tech 20+Years

< Previous | Next >

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x