Volvo 850 - Recent Questions, Troubleshooting & Support

This is a problem with the anti-theft system; its partially tripped which locks out the ignition. Disconnect the negative lead on your battery and turn the key in the ignition. Nothing should happen, as you have no power, however turning the key will insure that all power has been drained from the system. Now reconnect the lead, unlock your doors twice, and start your car.

Sometimes the electronic control module goes to sleep. Usually happens when you always unlock the car with the remote. Trying locking and unlocking the driver door several time to see if it clears up.

This is a common problem on these older Volvos. Try pulling up on the hood (after hitting the hood release in the car) and then push the latch in and then lift up again while pulling the latch out.

https://www.matthewsvolvosite.com/forums/viewtopic.php?t=6941 I found this one when working on mine. I hope it helps you.

timing is incorrect/usually have to find #1 cyl top dead cent then use camshaft alignment marks and then reinstall belt.

Volvo has had a lot of trouble with ABS control units. Yours will most likely need to be replaced. You can either replace it with an exchange unit from a Volvo parts supplier or send yours to BBA reman. in MA for repair.

Try a can of Lucas Transmission Slip - 100M - see if that helps. Something is sticking in there. This might free it up.

Probably not. There are often vacant positions in fuseboxes, relay boxes and the various other locations electrical and electronic equipment is sited.. If you need to locate the ABS ECU you need to discover the official location, which could be almost anywhere - behind the dash or behind kick panels, behind the glovebox...

Have you diagnosed the problem to be the head gasket, or are you guessing.

What are the symptoms.

I would be carrying out a compression check, and cylinder leakage test on all cylinders.

If it is a blown head gasket, it will need replacement, don't bother with any dodgy chemical sealer, it will not work.

Normally the ac shouldnt be starting when you turn on the vehicle. This shows that there is a faulty ac switch. You need to check the ac switch and then followed by the ac thermostat.

If you want to solve your problem, click on the link I attached https://www.reliable-store.com/products/volvo-850-service-repair-manual-1992-1996-download

This is a common problem with 850s. The speedometer is driven electrically, while the odometer is mechanical. There's a tiny little gear inside the odometer that runs it from a motor; it's no longer tied directly to a speedometer cable like older models. What happens is the gear gets old and brittle and loses teeth, at which point it can no longer turn the odometer. My wife's '96 850 had the same issue when I got it, and a little internet research turned up the answer above. There are companies that make replacement gears you can buy fairly cheaply, but it does require a fair amount of mechanical aptitude to pull the instrument panel and disassemble the speedometer assembly. One note of caution that I learned the hard way: you have to take the front cover off the instrument panel, exposing all of the gauges. Be very careful not to disturb the position of those little needles; I ended up messing up the gas gauge, speedometer and temperature gauge, and it took a lot of trial and error to get them put back in so they showed the right readings. If I recall correctly, I found instructions for doing the gear replacement online, but it's been so long that I don't have the web page(s) I found any more. A lot of times the manufacturer of the replacement gears have instructions on their web sites. IPD USA sells them and has instructions. 850 Odometer Gear

Outside of the oil filter, there aren't a lot of places oil can exit the engine under normal circumstances, but my wife's '96 850 had a similar problem. The source of the leak in her case was the dipstick tube. We'd had the transmission replaced a few months before, and as it turns out, they had to pull the engine and transmission as a unit in order to get the tranny out. (They Hayes manual says to drop the subframe beneath the car, but given a full auto shop, it was probably just as easy for them to just pull the entire assembly.) Anyway, in the process I assume they disconnected the dipstick to give themselves more room to work. From the looks of the o-ring between the block and the dipstick tube, it appears it got deformed when being reinstalled so it failed to seal correctly, letting the oil leak out of it. Between the action of the cooling fans on the radiator and wind coming through the grille while driving, it was throwing the oil all over the place, making it hard to determine exactly where it was coming from. I ended up wiping down the entire bottom of the engine, driving the car and looking for oil. Repeat several times until I finally isolated it to the dipstick. You can buy just the o-ring online for just a few bucks. That solved the majority of the issue for me, but then I found oil leaking out of the top of the dipstick as well! There's another o-ring there, but they don't sell those by themselves; you have to either buy the whole dipstick (without the tube) to get it, or take the old one to an auto parts store and try to match up the existing o-ring to something they have in stock. I found one that was close enough, and that seems to have put to bed my engine leaks. Of course, I don't imagine you've had your engine pulled, but since your car is almost of legal drinking age, it's entirely possible the seal has simply failed due to age. Definitely recommend replacing both the top and bottom seals. There's only one bolt holding the dipstick in place, so it's not hard to swap out the one between the tube and the block.

Don't know your engine size so pick the correct one for your motor:



2.3L 4-Cylinder Engines Firing Order: 1–3–4–2 Distributor Rotation: Clockwise



2.8L 6-Cylinder Engine Firing Order: 1–6–3–5–2–4 Distributor Rotation: Clockwise



2.9L 6-Cylinder Engines Firing Order: 1–5–3–6–2–4 Distributorless Ignition



2.3L and 2.4L 5-Cylinder Engines Firing Order: 1–2–4–5–3 Distributor Rotation: Counterclockwise

Sounds like its in limp mode, where the transmission has a problem and to protect the vehicle it will not go faster. Check online for the parts you need, its mostly a solenoid that fails, unless you blew 3rd gear or something.