Obd?

[vickyg]

Hi folks,
A forum search for OBD got me no hits so apologies if this is duplicated somewhere. Would a 93 940 have an OBD port? I thought it would and indeed under the arm rest is the port cover - but no port underneath! Could it be somewhere else or just hasn't got one.

Cheers,
Vicky

[gpl1968]

No, the OBD ports were fitted to 940s after 1995 and that opened up a whole can of worms.
Luckily you should have a test box attached to the nearside strut tower in the engine bay.
Full details and instructions for use are in the FAQ here: EngineOBDCodes

[Laird Scooby]

What Gavin said! ^^^^^

Also, contrary to popular belief, it wasn't until 1998 that it became mandatory to have OBD on a car but even then, it didn't have to be accessible by a generic code reader.
If memory serves, it was 2002 when it became mandatory for generic code readers to be able to access the DTCs so on a 1993 car, you're kind of lucky to have the diagnostic port with the built-in factory code reader on the suspension turret.

On the upside, unless you're unlucky you should get a dispensation on the emissions for the MoT as even when new, the B200F didn't meet the emissions regs for 1992 - when i remember the thread in question i'll post a link. It has links to the governement website that stipulates which engines/cars/years and what the emissions should be.

If you're looking to find a DTC to suggest a reason for the smoky engine/exhaust, i think you'll be disappointed though.

[vickyg]

Have found the Led test ports and will have a read. No Dave I wouldn't expect the diagnostics to help with smoke..

[gpl1968]

Originally Posted by Laird Scooby

Also, contrary to popular belief, it wasn't until 1998 that it became mandatory to have OBD on a car but even then, it didn't have to be accessible by a generic code reader.
If memory serves, it was 2002 when it became mandatory for generic code readers to be able to access the DTCs so on a 1993 car, you're kind of lucky to have the diagnostic port with the built-in factory code reader on the suspension turret.

OBD2 (USA) started in 1996, probably resulting in Volvo stopping sales of the 940 in North America in 1995. EOBD (Europe) came into force in 2001 if I recall correctly.
The benefit of the earlier OBD1 diagnostic box is it can access more channels than the later (not quite OBD2) ports. The earlier boxes can access SRS (airbags) and power seat diagnostics that would need a computer to test on my car :-(

[Laird Scooby]

Originally Posted by gpl1968

OBD2 (USA) started in 1996, probably resulting in Volvo stopping sales of the 940 in North America in 1995. EOBD (Europe) came into force in 2001 if I recall correctly.
The benefit of the earlier OBD1 diagnostic box is it can access more channels than the later (not quite OBD2) ports. The earlier boxes can access SRS (airbags) and power seat diagnostics that would need a computer to test on my car :-(

Are you referring purely to Volvo Gavin? If so we might be talking at cross-purposes as i was referring to OBD in general. I think Ford (Europe) were the first to use EOBD (Electronic On Board Diagnostics) in the very early 90s on the Escrot Mk4 and from there, the idea spread. I think Ford (USA) also introduced EOBD at the same time but whether they "borrowed" the idea from Ford (Europe) or the other way round i don't know.

[gpl1968]

Originally Posted by Laird Scooby

Are you referring purely to Volvo Gavin? If so we might be talking at cross-purposes as i was referring to OBD in general. I think Ford (Europe) were the first to use EOBD (Electronic On Board Diagnostics) in the very early 90s on the Escrot Mk4 and from there, the idea spread. I think Ford (USA) also introduced EOBD at the same time but whether they "borrowed" the idea from Ford (Europe) or the other way round i don't know.

No, just when the OBD2/EOBD protocols became mandatory on new vehicles. Obviously it made sense to implement OBD2 to new models if they were to be released close to those dates.
It does seem strange though, that Volvo did a major re-wire on the 940 including fitting the OBD2 port, but not implementing the OBD2 protocols for the diagnostics. Maybe they decided it ws not cost effective to modify the engine management system considering the projected lifespan of the car.

Edit: The history of diagnostics is more complicated than I thought. More info here

[Laird Scooby]

Originally Posted by gpl1968

No, just when the OBD2/EOBD protocols became mandatory on new vehicles. Obviously it made sense to implement OBD2 to new models if they were to be released close to those dates.
It does seem strange though, that Volvo did a major re-wire on the 940 including fitting the OBD2 port, but not implementing the OBD2 protocols for the diagnostics. Maybe they decided it ws not cost effective to modify the engine management system considering the projected lifespan of the car.

Edit: The history of diagnostics is more complicated than I thought. More info here

It's a lot more complicated than i remember it too!

Seems i had my dates a little bit out when i quoted them above, looks like i remember the date of the EU Directive rather than the date it had to happen by.

That aside, Volvo weren't alone with what they did on the 940, fitting the OBD-II socket but not adopting full OBD-II protocol and connections. Jeep did the same with the Mk1 Cherokee, Rover did the same with the 800 and i'm sure there were others. Those were all destined for being changed by their respective manufacturers in the near future.

Have to say though, although a good idea in theory, the fact they now have sensors monitoring other sensors and so many different DTCs that are really just a visual indication of the main symptom, they're not infallible. A friend who owns a 14 plate Aygo recently had a problem with the MIL appearing. Said the cat had failed on the DTC but it hadn't. What had in fact happened was she'd hit a big puddle which had rapidly cooled the cat so it appeared to the computer that it was no longer working - said puddle also caused a fault to appear on the ABS system too.

Wouldn't reset straightaway, left it a few days to dry out properly then reset it, no problems since.