Sorry, I posted in wrong forum yesterday - ugh. Apologies for re posting, I do not know how or if I could move it.

New to Volvo - first issue.

Just picked up a 96 850 5 spd w/128k for my son. From the vin the car is w/out EGR, w/air pump, w/elec control evap, Motronic 4.4 w/Rulo, TLEV (55). Test drove, no check eng light, no codes stored so I bought it. Few days later, bank 1 o2 sensor code (forgot the number) signal low or something like that. Cleared code, it came back and I just said @ 128k, we need sensors. Glad I did not buy them yet. Looking at them, they don't look that old at all. At the connectors, the white wires are still very white. I believe these were changed very recently. That being said, I think I have a wiring or ECU issue.

The scan tool I have is pretty good, Actron CP9580, I can see live data, graphs ect. 1st thing I noticed is I only see data for (1) o2 sensor. The car will not go "closed loop", stays open, actually says "open2".

I saw a few threads similar but looked like they had problems updating from Motronic 4.3 to 4.4.

If anyone has any advice where they would start looking or how they solved a similar issue it would be much appreciated. We have until Feb for inspection to find and fix. From what I have read so far, it will fail emissions in open loop - too rich.

Thank you for any help.

 

First thing you should do is disconnect both battery cables and tie them together for about 15 minutes. This will purge the ECU of any learned data and force it to relearn the o2 sensor, if indeed they are newish.

2nd: I would pull the sensor out of the exhaust to make sure it is Volvo or Bosch. If it is not, it needs to be replaced.

 

If it was sold new in the USA, then it would have originally had two O2 sensors. The OBD II cars all had a 2nd O2 sensor behind the catalytic converter, and they used this to check operation of the catalytic converter, but also they used it to correct the front O2 sensor. As the sensors get old, they drift rich, but the rear one lives longer and stays accurate longer than the front one. So all that to say look for the 2nd one behind the catalytic converter. They had long wiring, and the plug is bracketed on the transmission, same as the front O2 sensor.

Also, with your scantool you should be able to read actual voltage coming from the O2 sensors and be able to tell if they have any life in them. You could certainly have a wiring issue, but unfortunately I don't see any of us coming up with a breakout box. The wiring problems are pretty hard to work with beyond pulling the computers and checking indivisual circuits for continuity.

There are excellent wiring diagrams at volvowiringdiagrams.com

 

Thanks for the replies Gentlemen. I do indeed have a second sensor. Both look very new. Like I said, at the connector, the (2) white wires are very white. And the clip that I bet these mounted to is missing. They just hang, not melting on exhaust, but not secured to anything. I'll figure something out there.

This weekend I am going to try as rspi says, try to force them to re learn. Then I will pull one, not sure if I will be able to tell if they are Vovlo or Bosch but I will see what I can. The next step I was going to do is pull the ECU and try to check for continuity. Below is what my scan tool sees. I have reset the code many times and same consistant code. The MIL status says off, the code must be pending, show in freeze frame.

Really appreciate the replies. I know these are good cars and expect issues like this on a 20 year old car. I don't give up too easily. I am sure to have a few more questions.

Thanks again

MIL STATUS Off
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 840
CALC LOAD(%) 2.0
MAF(LB/M) 0.51
COOLANT(°F) 198
IGN ADV(°) 5.0
SECOND AIR ATMOS
ST FTRM1(%) 0.0
LT FTRM1(%) -5.5
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN2
FUEL SYS 2 N/A
O2S11(V) 0.485
ST FTRM11(%) 0.0

=====================

View Freeze Data

P0135 (MOD $17)

TROUB CODE P0135
ENG SPEED(RPM) 840
CALC LOAD(%) 2.0
COOLANT(°F) 212
ST FTRM1(%) 0.0
LT FTRM1(%) -7.0
VEH SPEED(MPH) 0
FUEL SYS 1 OPEN
FUEL SYS 2 N/A

 

Hmm.. It's rich. It looks awfully close on voltage, but the fuel trim is sort of a lot. The target is 0.45 volts. It may be open loop because no matter what it does, it can never get to 0.45 volts. I don't know what all can make it go open loop. Engine temperature makes it go open loop every day, but I don't know what other checks send it there.

 

Noticed over the weekend, if warm and driving will get closed loop and sometimes when lifting off gas - goes open. Caught it while driving. 3.5 seconds between frames - see below, only show before and after open. Out of 50 frames, approx 3 minutes only one open loop frame. Don't know about the values but I was glad to see them moving. Makes me feel better about the ECU. That was last nite.

I am in New Jersey, cold this morning lower 40's, started and immediate CEL. Same code P0135, sensor1 heater. Warmed it up, stayed open at idle. Took it for a short ride until it went closed. Returned and let idle, went open after a few minutes. Then I held about 2k rpm and goes closed. Let idle = open. I was able to repeat, thinking the sensor heater is the issue. Hot exhaust = closed loop. So I pulled the sensors. Both are Bosch. Not sure if the correct ones but I was fooled by the clean look of the wires. Not so new, see attached pic's. Rear looks like they put it in with a vise grip on the body, slightly crushed. Anyway I ordered both and will try that. Would you guys have done the same?

I have no service records but the owner stated their mechanic is the best and they know and used him forever. Well after almost breaking every wheel bolt, I have some doubt he was so good. Even I know a bolt = lower torque, 85lbs, these took a breaker bar with a 3' pipe to break them loose.

While I was under there I found the outer cv boot has just torn wide open - ugh. Ordered boot kits.

I may have paid too much for this car. $2500, 128k on it, interior clean, no rust at all, small dents, scratches but no hits. Next is timing belt then the suspension but not yet. Going to try to get thru to spring. FCP Euro has a kit with EVERYTHING. Did the glove test for PCV so not plugged up yet. Will do that in spring as well. Anyway I bought because it is for my 17 yr old son and I know it is safe. It is NOT fast at all which is not a bad thing. I know it will take money to get it to 200k but when I read you need to pull the motor to do the clutch I started doubting the purchase. He already knows how to drive a standard and he is very good keeping his foot of the pedal as well. The clutch has a small whine sometimes but does not slip at all. Do you guys think I paid too much? He loves the car, I hope I can keep up with it. Very local driving right now. College next year so I have until then to get it up to snuff. I have an 02 Chevy van w/150k and an 08 Cobalt w/160k as well to work on. I try to never bring my vehicle's to a shop. So far last 20+ years, wheel alignments and recalls only - everything else done in the driveway.

Thanks again for any replies/advice. Sorry for the short story.


FRAME: 8 TM: 28.4

MIL STATUS Off
ABSLT TPS(%) 14.1
ENG SPEED(RPM) 2010
CALC LOAD(%) 7.1
MAF(LB/M) 1.62
COOLANT(°F) 205
IGN ADV(°) 21.0
SECOND AIR ATMOS
ST FTRM1(%) -3.1
LT FTRM1(%) 0.0
VEH SPEED(MPH) 42
FUEL SYS 1 CLSD1
FUEL SYS 2 N/A
O2S11(V) 0.855
ST FTRM11(%) -2.3

---------------------

FRAME: 9 TM: 32.0

MIL STATUS Off
ABSLT TPS(%) 9.4
ENG SPEED(RPM) 2010
CALC LOAD(%) 3.5
MAF(LB/M) 0.86
COOLANT(°F) 205
IGN ADV(°) -7.5
SECOND AIR ATMOS
ST FTRM1(%) 0.0
LT FTRM1(%) 0.0
VEH SPEED(MPH) 41
FUEL SYS 1 OPEN1
FUEL SYS 2 N/A
O2S11(V) 0.930
ST FTRM11(%) -4.7

---------------------

FRAME: 10 TM: 35.5

MIL STATUS Off
ABSLT TPS(%) 23.1
ENG SPEED(RPM) 2100
CALC LOAD(%) 16.1
MAF(LB/M) 3.39
COOLANT(°F) 205
IGN ADV(°) 24.5
SECOND AIR ATMOS
ST FTRM1(%) 3.9
LT FTRM1(%) 0.0
VEH SPEED(MPH) 45
FUEL SYS 1 CLSD1
FUEL SYS 2 N/A
O2S11(V) 0.140
ST FTRM11(%) 3.1

---------------------

 

The heater should just have key on power, I think, but I could be wrong. If the heater is getting power, the heater may have burned out. I have not seen that code ever, so at least it doesn't seem common.

 

update - after changing an axle boot, installed new sensors. Started up and w/in 2 minutes went closed loop. Took for a quick ride, stayed closed - all seems good with the ECU. (1) problem solved.

Right after the boot job, I was planning on finding the powers steering drip (took 3 weeks before had to add) but my son needed the car. Came home with the pump screaming. Needless to say, I found the leak now. Got hoses need to get to it today. Is it as tough as it looks to get to the rack connections? Do you move the swaybar? I am going to try a crowsfoot, either way the hoses will come out. I hope the pump survived. If it was a donkey, he'd a killed it!

Thanks again for the reply.
Paul