Tranny Slip and Check Engine Light On After Battery Disconnect

Asked by Dec 28, 2009 at 03:40 PM about the 1998 Audi A4 1.8T quattro Sedan AWD

Question type: Maintenance & Repair

Hi,

Please help! I just bought a 1998 Audi A4 Quatro with the 1.8T. I drove the car for about 3 days and everything was great! The car did not come with a radio as the previous owner had an aftermarket and he removed it prior to selling the car to me. Yesterday, I drove the car and went out and bought a radio. I drive back to my house and everything's great. I remove the negative battery cable, install the new radio, reconnect the battery cable, and the check engine light is on. I try to drive around the block and the tranny is slipping into every gear. The car has no tranny leaks or any other leaks for that matter. Is there any way I disconnested a wire behind the radio or something? Seems extremely strange that the car was great until I installed a radio, and now engine light is on and tranny slips. Please please please help! This was a Christmas gift and now the car in not driveable.

Thanks in advance.

Jon

4 Answers

165

Anytime you disconnect the battery the ECU needs to "relearn" engine idle parameters, shift points etc. Also the ECU could have been flashed at a dealer with newer updated parameters which will have been lost when you disconnected the battery. Disconnect the battery again and let it sit for a few minutes. Reconnect the battery and start the car but do not touch the gas peddle or put it in gear. Let it idle, with all accessories turned off for about 2-3 minutes. Drive it until it's at normal operating temp(dont drive it hard) and let it idle for another 5 minutes. Turn it off and let it sit for 30 minutes.

2 of 2 people found this helpful.

I bought a 2001 Audi A4 1.8T, Avant on Saturday and everything was working fine. It drove perfectly. I than replaced some globes and fuses cause some lights did not work. In the process I left the lights on. I than fixed a jammed seatbelt. When I wanted to start the car, it did not want to start as the battery was too flat. I disconnected the batter and charged it. After a while I tried again, but with no luck. I tried different stuff in an attempt to start it again including disconnecting the ECU for an hour or so. Even up to today it does not start. The car never worked with the remote, although I have one, only with the keys. The guy from whom I bought the car had the keys made recently and it hasn't been coded. My concerns are: (1) does the seatbelt have an effect? (2) does the key need to recoded or what? Can somebody help me please?

I have a 1998 audi a6 quattro the front trans seal went out an im replacing the tranny but when i lowwer the trans it pull down on my ecu plug i need help its my first time

how do u reset engine light

Your Answer

A4

Looking for a Used A4 in your area?

CarGurus has 12,240 nationwide A4 listings starting at $1,899.

ZIP:

Audi A4 Experts

  • #1
    Deathjam4
    Reputation
    3,720
  • #2
    lukeyramone
    Reputation
    560
  • #3
    Tom Demyan
    Reputation
    470
View All

Related Models For Sale

Used BMW 3 Series
1,090 Great Deals out of 33,844 listings starting at $1,000
Used Audi A6
145 Great Deals out of 7,390 listings starting at $1,595
Used Mercedes-Benz C-Class
777 Great Deals out of 29,201 listings starting at $1,500
Used Audi S4
42 Great Deals out of 1,743 listings starting at $3,500
Used Audi A3
116 Great Deals out of 5,728 listings starting at $3,995
Used BMW 5 Series
514 Great Deals out of 15,891 listings starting at $1,500
Used Honda Accord
1,107 Great Deals out of 65,887 listings starting at $561
Used Ford Mustang
560 Great Deals out of 36,550 listings starting at $1,500
Used Audi A8
71 Great Deals out of 1,938 listings starting at $3,995
Used Mercedes-Benz E-Class
671 Great Deals out of 22,132 listings starting at $1,500
Used Honda Civic
736 Great Deals out of 65,148 listings starting at $1,350
Used Chevrolet Camaro
466 Great Deals out of 31,525 listings starting at $3,550

Used Cars For Sale

2018 Audi A4 For Sale
4,806 listings starting at $34,441
2017 Audi A4 For Sale
65 Great Deals out of 1,727 listings starting at $19,500
2016 Audi A4 For Sale
14 Great Deals out of 226 listings starting at $19,995
2015 Audi A4 For Sale
35 Great Deals out of 790 listings starting at $12,994
2014 Audi A4 For Sale
58 Great Deals out of 925 listings starting at $11,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.