flashing up arrow on my 850 uk. read inside, please

hi

just noticed that my up arrow is flashing on the dash, i seem to have no trouble with my auto box, but also the mode light is flashing. in the centre console, i have heard that you can first of all clean the switch, then if that does not work, replace it, how difficult to clean/replace,

i used to be a mechanic, but a long time ago. so would like to have a go, but also do i have to get rid of the error codes, as i have a 1996

850 and cannot reset from under the bonnet, or have the reset button on the dash, ( as i am told some models/years have this) maybe could build a obdII interface to reset the codes. my present job involves electronics, but have seen no kits in the uk. i have seen downloadeable software on some sites.

any help would be most welcome .

col

Reply to
colin
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First, you need to have the error code read. It may be something that a little preventive service can prevent a major breakdowm. Usually for minor things, the flashing lights will reset themselves after several days. For major things, it is just an early warning that the inevitable is coming. The '95 and some '96 transmissions would fail between 80,000 miles and 130,000 miles. There should be lots of rebuilt transmissions available now and some recycling yards (junk yards) may have some newer ones.

Reply to
Stephen Henning

I was told by two Boston-area Volvo dealers' service departments that the flashing up arrow, combined with the flashing lights on the console, means "time to buy a new $4K transmission."

Some posters to this group believe it means "time to clean or replace your $130 PNP switch."

Who are you going to believe, two certified Volvo service departments or a bunch of web geeks?

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-RL

Reply to
Robert Lutwak

If you read the codes, it tells if the PNP switch is the candidate. The PNP switch problem showed itself in my '95 850 when I would shift the automatic transmission manually. When I would downshift, sometimes I got the error. The Error Codes said something like wrong speed ratio. That could have meant it was the input speed sensor, the output speed sensor or the PNP switch. In my case it was the PNP switch and it usually is. Unfortunately the dealer replaced that last. In my case, since it only did it when I was in "3rd" gear, it should have been obvious to the mechanic what the problem was. The problem was that the "service writer" never told the mechanic it only occurred in "3rd" gear. When a "service writer" starts diagnosing or is too lazy to type in what the customer reports the problem to be, that is a big problem. The mechanics are highly trained, the "service writers" aren't. My dealership goes through "service writers" on a regular basis. The mechanics stay.

Reply to
Stephen Henning

Reply to
Mike F

I get the flashing up arrow on my '96 850 this time of year here in CT (cold and damp conditions). My problem is due to the PNP switch, but rather than replacing it (since it only gives the failure when it's damp first thing in the morning), I live with the problem. What I did was to go into the transmission module under the hood and modify the memory chip to not store the fault code (by lifting 1 pin). That way, the CE light does not get stuck on and the transmission doesn't stay in limp mode. All I have to do is to shut the engine off for a few seconds, then restart and I'm good to go with no fault! If you leave the fault set, the transmission stays in "safe" mode and only runs in 3rd gear. It's a poor design by Volvo to have a switch that is subject to condensation cause such expensive repairs for unsuspecting owners. I wonder how many transmissions were replaced over the years because of this stupid switch issue??

Replacing the switch is fairly easy, but I refuse to shell out good money for a once or twice a year problem.

Bob

Reply to
rd

thanks for that, i think the problem is electrical, as my auto box changes perfectly, no sticking in gears ect.the box changes gear no problem, just the lights on. is the module in the pnp switch ? and can i get at it easily?

col

Reply to
colin

That is not the way my '95 850 works. If I shut off the engine for 2 seconds and restart, even if I keep coasting at highway speed in neutral, the transmission goes out of limp mode and everything works normally. In a couple days the yellow light goes off by itself. Of course now that I fixed the PNP switch, it never comes on anymore.

Reply to
Stephen Henning

Sounds like the problem in my car. The transmission module is along the passenger side fender well, in a covered box. Lift off the cover and you will see 2 units. If I recall, the one closest to the fender is the tranny module. Be VERY careful messing with this unit as they are $$$ to relplace. I have quite a bit of electrical experience soldering surface mount components. The part you are looking for is an

8 pin SOIC NVM EEProm chip. If you can understand this, than you will probably be ok if you are comfortable with surface mount soldering. You will need to either lift or snip the write enable (WE/) pin on the chip.

Reply to
rd

On my 96 I get a constant CE light cause the transmision module stores the fault. The problem is that you can't reset the CE fault with a normal OBDII reset tool as with a normal emissions problem, since the fault code is coming from the transmission module. You need the Volvo reset tool to reset the transmission error code. Otherwise there would be no need to modify the tranny module to not store the fault. I still get the CE light and limp mode, but it goes away when the car is shut off.

You probably have a different problem if you are getting the CE/limp mode at hiway speeds. Mine ALWAYS happens on the first shift (into reverse) coming out of the garage in the morning. After that, it's ok.

Another "trick" I learned from a Volvo tech is (with the car off!) to move the shift lever through all the positions about 30-40 times. This wipes the contacts clean on the PNP switch.

Bob

Reply to
rd

Reply to
colin

Those wer ethe symptoms on my 94.. Shifts perfectly, usually comes on when I move the lever. One way to test: Before starting, run the lever through it's full travel 5 or more times. This wipes the contacts, hopefully pushing any contaminants aside (The switch is filled with grease) If it fails less often after doing this, it's the PNP switch.

Not too hard to get at, but you need an alignment tool to get the switch body aligned with the neutral detent on the transmission control shaft. I made one from acrylic plastic that fit over the flats on the shaft and indicated the center line between them.

The hardest part was removing the switch connector. The switch wires end at a plastic connector block that fits into a larger connector assembly that;'s bolted to the transmission housing, It shares this space with another block that probably carries the rest of the trans interface. It was a real pain to unlatch the block and work the wires through the grommet.

Instructions and pics here:

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Reply to
Doug Warner

hi i did move the lever about 20 times last night, and guess what the light has gone off, i did think it would stay on as it maybe logged an error code, so will keep fingers crossed, if happens again i have printed the instructions off the volvo speed site, and will have a go at repair/clean

thanks for all the help. col

Reply to
colin

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