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

155

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 out of 2 people think this is 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

Add photo

Related Questions

A4

Looking for a Used A4 in your area?

CarGurus has 10,824 nationwide A4 listings starting at $1,899.

ZIP:

Search Audi A4 Questions

Audi A4 Experts

#1 Deathjam4
Deathjam4
Reputation 3,210
#2 lukeyramone
lukeyramone
Reputation 520
#3 Tom Demyan
Tom Demyan
Reputation 390
View All

Related Models For Sale

Used BMW 3 Series
978 Great Deals out of 31,676 listings starting at $1,000
Used Audi A6
157 Great Deals out of 6,410 listings starting at $2,799
Used Mercedes-Benz C-Class
458 Great Deals out of 26,530 listings starting at $2,000
Used Audi S4
42 Great Deals out of 1,576 listings starting at $4,500
Used Audi A3
61 Great Deals out of 6,319 listings starting at $3,700
Used BMW 5 Series
491 Great Deals out of 15,928 listings starting at $1,700
Used Honda Accord
803 Great Deals out of 84,448 listings starting at $988
Used Ford Mustang
459 Great Deals out of 45,641 listings starting at $1,999
Used Audi A8
40 Great Deals out of 2,030 listings starting at $3,490
Used Chevrolet Camaro
219 Great Deals out of 30,798 listings starting at $1,217
Used Mercedes-Benz E-Class
409 Great Deals out of 19,898 listings starting at $699
Used Honda Civic
634 Great Deals out of 88,620 listings starting at $995

Used Cars For Sale

2017 Audi A4 For Sale
38 Great Deals out of 4,816 listings starting at $27,999
2016 Audi A4 For Sale
11 Great Deals out of 211 listings starting at $24,488
2015 Audi A4 For Sale
7 Great Deals out of 329 listings starting at $19,000
2014 Audi A4 For Sale
40 Great Deals out of 1,271 listings starting at $14,988
2013 Audi A4 For Sale
18 Great Deals out of 460 listings starting at $11,250

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.