[gward]

I have 1999 s80 my wife and I brought used last year at a dealership in SC. The car has been great until recently. It first started with the position light failure warning (which all the lights were working) then next the STC lights came on, next the ABS warning, the check engine, the SRS airbag, and the brake failure warning (which tells us to stop ASAP). Now the Dash looks like a Christmas tree or no lights at all. The car was running smooth with the warning lights on when we took it in to have it checked out at the dealership. After spending most of the day on diagnostic machine the car had 12 codes. The next day the service manager tells me that he is not 100% sure what the problem is. Then he tells me that the valves are bent or the seats are bad due to a compression test they done on the cylinders. 2 were at 140, the rest were 80 to 30. If this was the case the car would run ragged before we took it to be checked. But it ran fine with no skipping before, in fact, a local mechanic drove the car and stated that nothing was wrong mechanical but recommended we take it to the dealership in order to put it on the computer. The service manager told my wife it would take 3600.00 + to fix the motor and depending on which module was bad 1 to 2 thousand each with no guarantee that would fix the problem which he doesn't know for sure. I thought that all this diagnostics could pinpoint the problem. My wife paid the 250.00 for the diagnostics and drove the car home skipping and back firing. Our car ran fine before we took it to the dealership and it left there skipping something awful. I am not a professional mechanic but I do know something is not right with this situation. Now, I have a car that left my house driveable and left the dealership not driveable. Any help on this matter would be greatly appreciated.

Thanks

 

[Tech]

Look at your receipt and tell me which codes they pulled and fault traced.I can help you a little more after that.

 

[Vitor]

Your problems may be a bit too complicated now.
You are correct in assuming that there were no valve problems when you took the car to the dealer. An engine with low compression in so many cylinders may not even start.

You will need to verify the compression in each cylinder to make sure of the values.
If you in fact have low compression in 5 cylinders, then the head will need to be removed to find out why the damage took place.

Now, here's something else.
I have a 99 S80 T6, one of four Volvos I have. I am the one who rebuilds the ABS/STC control units.
One of the problems you described is your problem with the ABS/STC unit.
When I repair an ABS unit, I install it on my S80 and put it through its paces to make sure all functions work. Sometimes I remove the unit I'm testing and don't install a unit on the car because, I tell myself, I will do it later.
When I jump on the car and drive away, at least 4 warning lights will turn ON and if I ignore them long enough, I get the engine to start misfiring and in one instance I lost the use of the throttle.
When I re-install the ABS/STC unit all problems will go away and the car is back to normal.

Check my website for more ABS/STC information.
Vitor's Volvo ABS website

 

[gward]

QUOTE(Vitor @ Feb 28 2005, 03:37 PM)Your problems may be a bit too complicated now.
You are correct in assuming that there were no valve problems when you took the car to the dealer. An engine with low compression in so many cylinders may not even start.

You will need to verify the compression in each cylinder to make sure of the values.
If you in fact have low compression in 5 cylinders, then the head will need to be removed to find out why the damage took place.

Now, here's something else.
I have a 99 S80 T6, one of four Volvos I have. I am the one who rebuilds the ABS/STC control units.
One of the problems you described is your problem with the ABS/STC unit.
When I repair an ABS unit, I install it on my S80 and put it through its paces to make sure all functions work. Sometimes I remove the unit I'm testing and don't install a unit on the car because, I tell myself, I will do it later.
When I jump on the car and drive away, at least 4 warning lights will turn ON and if I ignore them long enough, I get the engine to start misfiring and in one instance I lost the use of the throttle.
When I re-install the ABS/STC unit all problems will go away and the car is back to normal.

Check my website for more ABS/STC information.
Vitor's Volvo ABS website

[snapback]4198[/snapback]​

You are correct in that it is very complicated. First, I am going to concentrate on the engine. I have a friend that can check the compression (I can do it, but I don't have the extra time) and go from there. I have been told that the timing belt has broke but this isn't the case. The car will start and run but it's rough. I brought the car used last year with 84,000 miles. Before that we had an 850 with +175 K miles so I know these cars will go the distance. It now has 117K now. I called the dealership I bought it from and they told me that the belt needs to be replaced @ 105K. Right now my wife is in college 5 days a week so she hasn't have a chance to replace it yet. Enough on the history of the car. I asked the dealer if the timing belt was able to ride over (jump a notch or two) to get off time in order to warp a few valves. He said no that most of the time it just breaks. This hasn't happened. It still runs. I also asked if the tensioner broke or lose tension and caused this. Again, this was unlikely as the belt would snap. I plan to check the compression. If it is low then I will have to go into the motor. If not, is it possible that these abs/stc and other modules are trying to shut the car down? I going to try this first and go from there. I check my receipt and it doesn't have any codes on it. Thanks!

 

[Vitor]

While the compression is checked, put a new set of spark plugs.
Note the condition of the old plugs.
While the compression test is done, make sure the ECU fuse is removed so the ignition coils don't get damaged, and the injectors are not flooding the cylinders.

Make sure a vaccum hose was not left disconnected (double check this) specially the intake hoses.

Clear the codes in memory by disconnecting the battery for 10 min (make sure you know the radio code).

Re-start the car and see what happens.

 

[Tech]

Also while you are in buy the spark plugs pull the rubber boots down on the coils and check for cracks on the coils.The coils crack from the heat then will not fire at times.That is becoming a problem as the cars get older.We replace them all the time at the dealer for being cracked and causing running problems.Also if you pull the fuse for the ECM that will reset the computer system if it is out for more than 10 min.It is like disconnecting the battery for 10 min.

 

[gward]

Thanks guys. I'll try that first.

 

[Tech]

Let us know how you make out!!!

 

[Omni4xint1]

Hey Guys,
I have the same problem with my 99 S80, but also the brake failure light also comes on. I just had my brakes done about 2 months ago. Can someone give me even the slightest hint as to what is happening?