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

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 11,137 nationwide A4 listings starting at $1,500.

ZIP:

Audi A4 Experts

  • #1
    Deathjam4
    Reputation
    3,640
  • #2
    lukeyramone
    Reputation
    560
  • #3
    Tom Demyan
    Reputation
    470
View All

Related Models For Sale

Used BMW 3 Series
1,116 Great Deals out of 32,629 listings starting at $1,000
Used Audi A6
129 Great Deals out of 6,477 listings starting at $1,995
Used Audi S4
53 Great Deals out of 1,671 listings starting at $3,995
Used Mercedes-Benz C-Class
595 Great Deals out of 25,389 listings starting at $1,995
Used Audi A3
97 Great Deals out of 4,797 listings starting at $3,250
Used BMW 5 Series
451 Great Deals out of 16,246 listings starting at $1,995
Used Honda Accord
1,032 Great Deals out of 60,523 listings starting at $999
Used Ford Mustang
712 Great Deals out of 38,398 listings starting at $895
Used Chevrolet Camaro
385 Great Deals out of 30,498 listings starting at $3,500
Used Audi A8
67 Great Deals out of 2,052 listings starting at $2,450
Used Mercedes-Benz E-Class
471 Great Deals out of 19,709 listings starting at $1,400

Used Cars For Sale

2018 Audi A4 For Sale
2,883 listings starting at $35,191
2017 Audi A4 For Sale
37 Great Deals out of 2,168 listings starting at $24,998
2016 Audi A4 For Sale
10 Great Deals out of 224 listings starting at $21,488
2015 Audi A4 For Sale
16 Great Deals out of 605 listings starting at $14,991
2014 Audi A4 For Sale
74 Great Deals out of 1,252 listings starting at $12,995

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.