850 Wagon 1994 stumbles at times / shakes when slowing down

Post by **biggytwo** » 02 Dec 2009, 04:55

The problem started just recently on the wagon (236,500 miles on it) where at times when slowing down the car starts shaking and runs real rough, but when put it in neutral the shaking stops. My son usually drives the car and he said that this does not happen all the time either. I took the car out for a test and it felt like a hard shift at about 45 MPH (slight "thunk") and then too it shook when I came up to a stop light and I had to put in in neutral to prevent the car from dying.

It has an automatic transmission and I did the fluid drain and fill method on it at 220,000 miles or so. Color of the fluid is still red.

Also I pulled the code from the A1 socket and it only flashed one code: "1-2-4", but I also noted that the OBD light was a dim red color at all times, even after clearing the code. It did brighten up when the button was pressed to read the code. There was no "Check engine light" on either before checking the codes.

A2 socket acted normal, no dim glow and flashed a bright red: "1-1-1".

Any ideas for the cause of the problem of the code? From what I found, is it "Mode selector faulty or short circuit to ground"? And if it is, what could the fix be?

Thanks,
Steve

FCPEURO · Post by **FCPEURO** » 02 Dec 2009, 07:59

This is what the A1 code is.

124 Mode selector faulty or short circuit to ground

I am not sure what that code means. I think it has something to do with the switch that switches the car from eco mode to sport mode. This could affect the shift points if it is jumping back and forth between each mode.

Post by **jblackburn** » 02 Dec 2009, 08:58

Out of curiosity, try cleaning your mass airflow sensor. When I started having problems with mine it idled funny after letting off the gas.

Post by **biggytwo** » 07 Dec 2009, 17:30

Thanks for the suggestions...I took it in to the Volvo dealer at my wife's strong suggestion (*I think she does not trust my mechanical ability*) ...and they could not duplicate the problem, but during the inspection, they stated that the rear calipers are seized or not working right.

Since I recently had our local garage do the brakes, except rear calipers, I declined the Volvo offer for them to fix the rear brakes and made an appointment to have them checked by the local garage. They checked and confirmed that the left rear caliper was putting a drag on the the wheel and they would look at it later this week, but it was OK to drive.

Then after leaving his shop today and during a hard stop, the car shook and stalled out.. it restarted OK and I was able to drive it, but it seemed to have a drag on it. When I started the car again 4 hours later the car would not go into gear (reverse or forward) without stalling. In neutral and park the car idled fine. After several attempts going back and forth the car went into gear without stalling and I was able to get it to his shop for him to work on later this week.

QUESTION: is it possible that maybe during the hard stop (braking), that the left brake locked to the rotor and that is what is causing the problem of the car stalling out when putting it into gear?

And by driving a short distance once the car is going that the caliper releases slightly?

Thanks for any thoughts on this matter.
Steve

Post by **jblackburn** » 07 Dec 2009, 17:48

No, the sticking brake has nothing to do with the car stalling. I'm wondering if your torque converter is somehow "forgetting" to disengage (which it does at ~45, where you said you heard a loud thunk earlier). This would cause it to stall as soon as it's put into gear and when slowing down too, it's like forgetting to push in the clutch on a manual when you slow down. There is probably a bad/intermittent solenoid that controls this lock-up.

Out of curiosity, with your previous 1-2-4 code, try rowing the shifter back and forth between P and L 15-20 times and see if it improves anything.

Post by **jblackburn** » 07 Dec 2009, 17:59

Here's some more info for you to digest:

http://www.volvoclub.org.uk/tech/servic ... gnosis.pdf

http://volvoforums.com/forum/showthread.php?t=13786

As far as getting the part, give Daryl Waltrip or your nearby dealer a call.

Post by **biggytwo** » 07 Dec 2009, 19:37

Thanks..I will sure take a look into these possibilities. Hopefully it will not be too expensive of a repair. But I am puzzled as to why the CEL is not on or why there were no other codes in A1 of the OBD?

Post by **jblackburn** » 07 Dec 2009, 22:43

i don't have an answer for you there other than it takes multiple cases of a code occurring for the car to turn on the check engine light. also, i THINK as far as it could tell, the transmission was still shifting correctly in that the torque conveter was not SLIPPING (which it has a code for), its just probably permanently stuck in lock now since that hard stop you mentioned when it didnt have time to downshift and unlock the converter before coming to a stop, and it would only happen intermittently before that, but maybe not enough to flash the arrow or post a code.

Post by **biggytwo** » 21 Dec 2009, 07:45

Update:

I took the winter sport economy switch out and cleaned it up best I could. It seems to work as far as I can test it..higher shift point in the sport mode, but the car still has a problem.

The local shop replaced one rear caliper (less than $100.00 to do it - dealer wanted $670 to do both rear brakes - pads, rotors, calipers). The local shop also thought it might be a mass air flow sensor problem and they cleaned it and the car ran fine for them. I also wanted them to change the thermostat since the gauge has only been going to the 5:00 o'clock position recently, but they were afraid to do it because the bolts would not budge, so they did not do it.

Car ran fine at first when I picked it up, but about 4 miles later on the way home the car started to stall out and engine would almost die, but idled fine unless put into neutral. I made it home and found that with the engine in gear (sport mode) the RPM's now go up and down between ~ 500 RPM and 1500 RPM and it repeated the fluctuation.

I called the mechanic back and he thinks it still might be the mass air flow sensor or EGR and I'll be taking the car back to him.

The "check engine" light is not on and the problem now seems to be occurring when the engine has warmed up (about 4 miles of travel).

As an added part to the puzzle: two weeks ago when I started the car with the engine cold, it died numerous times when put into any gear (car would shudder and stall out) but idled fine in neutral or park. After starting it and putting it into reverse several times, it died those times, and then I started the car in neutral and put it into drive several times it died. After about 15 attempts and threatening the car by telling it I would call a tow truck, it finely did move a little in reverse and then moved a little forward in drive, to the point where it went into gear and I was able to get it to the local shop.

Very frustrating - I miss the heated seats.

Steve

Post by **jblackburn** » 21 Dec 2009, 07:52

Car ran fine at first when I picked it up, but about 4 miles later on the way home the car started to stall out and engine would almost die, but idled fine unless put into neutral

So it tried to die out in neutral too?

When you take it back to the mechanic, have him try to clean the idle control valve along with the MAF. That could give you the surging RPMs and strange stalling issues as well.