Hello all. I recently purchased an 84 850 Turbo wagon with 104K on it. It had a reasonably good service record and after I got it home, I cleared the codes (knock sensor and something about the cruise control) and reset the service light. No codes returned.

I replaced the cabin air filter, spark plugs, plug wires, cap, and rotor with OEM parts. I swapped out the OEM air filter with a K&N. I flushed & filled the trans with Mobil synthetic, and changed the oil to Mobil One and used an OEM filter. I also pulled and cleaned the throttle body, replaced the turbo oil line seals, replaced the thermostat and fixed a vacuum leak. You get the picture.

I have put about 1000 miles on the car and it has performed flawlessly. On the way home today, I got the dreaded check engine light. Here are my codes:

A2: 143:knock sensor, front: signal missing or faulty
B1: 211: driver's side damper motor position sensor: open circuit or short circuit to supply voltage
A7: 122: ECT sensor interval too long
A7: 113: fuel level sensor open circuit

Now it gets wierd
A6: nothing. No 111, nothing

Even wierder, I can't clear any of the codes. Just to double check, get all the codes off any given socket, then do the 5 second press, wait 3 seconds for the light to come back on, another 5 second press, then release and check codes as normal. Right?

Here are my questions:
1) Is the timing automatically retarded when you get a knock sensor code? This is something I read on another site.

2) On a car of that vintage, is it the knock sensor, wiring or crappy gas that usually causes the code? I've been using 92 octane unleaded, but I can switch brands if need be. I have not noticed any ignition pinging.

3) What the heck does that B1: 211 code mean? I was driving to work this morning and saw that the Recirc and AC Off indicator lights were flashing in unison. I turned off the fan and reset the temp controls on both sides to 70 from where they were at 60. Is the code related to this and why did those lights flash?

4) How do I clear those codes?

Thanks for your help,
Bert

Just a note on the knock sensor: I recall reading (here) that it is very
particular about being tourqed correctly (I suppose it is a sensor under
stress). So, if it is replaced, make sure the person doing it knows
what they are doing and has a tourqe wrench thats callibarted for low
torque settings (14.76 lbs for the sensor(s) on my 98).

The info at alldatadiy.com describes how the sensor works but not what
happens if it fails (that is, it did not say if the timing is retarted).
It also describes the steps to replace. Cost is $25 a year to subscribe
to alldata (I don't work for them but find the data useful).

the flashing AC panel lights mean that there is a malfunction in the ECC system (AC) my AC panel lights have flashed since i owned the car, tha AC is very cold and has no leaks.

Volvo gave me a bunch of crap about needing to do a AC service check and diagnose the problem you know $$$$, first of all i have to freon leaks so why do they need to service the system? $$$$, the codes are readable through the ECU but you need a VST volvo service tool to read them my OBD-2 will not read the AC just Chasis, SIPS, ECU, TRANNY, codes basically. not the AC stuff. so all vovlo really needs to do is hook up the computer, read the codes and quote the repair.

If your ac is cold and holds pressure then the problem is most likely electrical like a internal Temp sensor in the cabin is bad.

Like Mrsha said if the car runs good and the AC is cold, just disconnect the battery to clear the codes and drive it till it has a real problem, forget about the stuff, it sounds like a nousiance problem.

Dan

I can only tell you what I know.. 1994 model have some problem with ECU not much we can do here..

141. front knock sensor.. 1994 have deffect bad connection for front knock sensor volvo have a up grade kit for $80 without labor it come with 2 sensor both front and back.. ... >>>> now I do the up grade kit on my car it last for 2 week and code 141 come back and never go away not much I can do..

so up grade often will not solve 141 code..

now dealer tell 2 week ago since we all know 1994 have some ECU problem when it come to clear the code.. the best way to remove it from memory completly is to disconnected the battary over night and reconnect next day .. this action will clear code 141 if this is the memory problem... I have done mine yes but plan to do it soon..

the rest off the code are all balonie just clear them and forget them 99% it will never come back again..

my engien check light is on all the time .. many people just put a piece of black tape over the light and forget about it.. if the run good why worried..

as for code that you can not clear wall away come back few day later it will clear for you this happend to me all the time... some thing the 93-95 years small little bug...

go to www.volvospeed.com great site for 850 owner car...how to repair...