How to use the On-Board Diagnostic (OBD) unit.

[billofdurham]

Very interesting. OBD1, the box in the engine compartment, was phased out on the late '95 models as international standards dictated that OBD11 had to be adopted by all manufacturers from the '96 models. Volvo '96 models would start about September '95.

I have a '95 registered but '96 model 850 which has OBD11 and I have tried five scanners which failed to work on it but do work on '96 Fords and Renaults. The OBD11 protocol used by Volvo on UK cars precludes the use of DIY scanners. However,like you, I made my own and it is good enough to get the codes.

To access the relays you don't need to remove the radio, unless you have an after-market unit fitted which takes up space not normally used for the radio.

To access relays, remove the ashtray by pushing the spring clip at the top and the fuse panel cover by pushing the plastic snap at the bottom. Then remove the snap-on cover over the cigarette lighter with your fingernail or a small screwdriver. Remove the two Philips screws securing the storage box: one of these is angled in. Remove the storage box by gently tugging on the left side, pulling it and the cigar lighter wire out from the console. Beneath it you will see the relay tray behind the fuses. The relay tray can be pulled further out by releasing the white catch on the left towards back of relay panel, back meaning towards back of the car. Push this to the left and then lift the relay board up at least 1/2 inch before pulling the tray is rearward and out. It can be pulled a fair way out to enable work on the relay board.

A faulty relay can cause a parasitic draw on the battery and, given enough time, it will cause it to go flat.

Bill.

[rickb78]

Hello, have read the previous posts on the OBD. Have 91 740. I wanted to access the codes and so plugged into #2 then pushed the button down and counted one one thousand. The LED just flashes non stop. I have no idea what that means. Does anyone else?

[rickb78]

Ok, I figured it out. The code it throws is 1-2-2, air temp sensor signal. I'll check the forum to see if there's any info this sensor.

[nhcowboy]

Have a '93 245. Found the OBD - no problem. But some idiot left it plugged in and uncovered - so it's dead as a doornail! Pushing the button gets zero response from the LED light. So . . . is there any chance it can be repaired? What about replaced? It's such a handy tool - I hate not to have it available for use.

And, at the moment, my "Check Engine" light is on . . . so this little diagnostic device would sure be helpful to have!

[Manuel in Cabo]

Hello fellow Volvo owners. I have a 1995, 850, turbo wagon. My mechanic has always plugged in his scanner and diagnosed the car. Now the scanner reads nothing but the car runs (badly).
My question is 'How do you use the OBD"? Can somebody aid me to understand the use process. I live in Cabo San Lucas, Mexico. I cant just drive the car to the local volvo dealer, doesnt exist.
Thank you
Manuel
[email protected]

[icthus]

The American 780 Bertone has no such box. Where is it on this car? I find nothing in the engine compartment.

[billofdurham]

Welcome to Matthew's Volvo Site.

If you have the turbo engine the '89 780 wasn't fitted with the OBD unit. This was done on the '90 turbo models.

Bill.

[Davie Motors]

GREAT THREAD

[dalerowsey]

I have a 1992 volvo 240 sedan. How do i use the obd unit?

[billofdurham]

Welcome to Matthew's Volvo Site.

The instructions at the beginning of this topic cover your car.

Bill.