My car shows a Lambda light fault as soon as it is warm, and begins to sputter. It is a 1996 940 wagon with B230fk engine, made in Sweden. The light will stay on after restart, and it will restart. I can reset the warning light by disconnecting the batter and letting the car cool down. Fortunately, I can repeat the fault when restarting.

Unfortunately, I have not been able to retrieve the fault code. I tried 3 or 4 different brands of OBD2 readers, and none of them are able to connect, using the OBD2 port in the center console. There is NO other diagnostic device in the engine compartment.

First of all, is there an OBD2 reader that can communicate with the car? Do you know of any specific brand/model of reader that works with this model?

Secondly, if I am not able to get hints from a reader, I would have to try to troubleshoot the sensors, the connectors, the vacuum tubes, to the fuel mixture computer, and I should check if my throttle body might need cleaning.

Would you happen to know what takes place when the car warms up? I am looking for the best path for troubleshooting? Not having reliable diagnostics is a daunting task, and would require a lot of luck. I am trying to avoid throwing money at it, and so I am trying to learn where it has gone wrong. It may be a simple problem.

 

Yes you need a scan tool that talks to ~1987 to 1998 Volvos like one of the three models pictured. You should be able to find a 1996-1998 compatible tool. 99 and up use use a different communication protocol.

 

OBD 1 or 2 is an industry wide thing, at least in the US and all cars sold staring with 1996 MY have OBD 2. That I hear is the reason why the 940's last MY in the US is the 1995--they didn't want to go to the expense of converting a line slated to end. The OBD port in the middle was used in the 850 line but that was the OBD2 with the reader we all use since 1996. I have never seen a reader designed to work with OBD1, usually it's some flashing light thing so no reader needed, not for Volvo anyway. If you have a OBD2 port that doesn't connect then maybe you have a wiring problem somewhere.

 

I have a VST my shop used that reads all ~1987-1998 Volvos. Different software cartridges are swapped when needed. The OBD1 codes come out in a text form on the ~1987 to 1995 cars. Those cars use the 6 pin adapter clrcled in green (alligator clips to + and - on battery) to add a obd2 port under the hood. 96-98 plugs directly into the obd port in the interior. Supposedly able to calibrate the c70 convertible tops until 2004 with it also. It's for sale if you know someone interested!

 

Did not know that, thanks! Was this strictly a Volvo tool? Can it be used on other brands?

 

It's the factory tool from back then - I have other cartridges for generic odb and cartridges and cables to talk to a variety of 99+ cars also. The 99+ stuff never worked as well as VIDA or my Snapon scan tool.

https://ohiodiagnostics.com/volvo/ is where i get parts and service for it.

 

That would be great if I worked on more Volvos, but I only have 1, which I am trying to keep around for as long as possible. It seems I may have to rig one of these blinking Flash code readers. This one hilariously uses an anti-perspirant bottle:

https://www.matthewsvolvosite.com/fo...ic.php?t=60660

I wonder how much voltage comes out of these ports, and what kind of LED I would need. I think the typical LED needs less than 4 volts.

 

Do you if these scan tools provide live data ("real time") of a 1996 940, particularly Fuel Trim information?

 

Still have not been able to rig up a blinking scan tool, as my battery drained out, and is still recharging. Although poking around and tracing the vacuum lines, I think I am now much closer to the problem. It seem some vacuum hoses through the EGR system dried up, and fell off....

This if for a B230FK.


Hose #7 was completely disconnected from the EGR valve (#14). I also noticed a lot more brittle vacuum hoses, so I will set out to replace the vacuum hoses first to see if I still get the error. Afterwards, i will overhaul the air intake, throttle body, and the fuel injectors, so I can get a closer look at the damage with the EGR valve (#14).

Do you have any advice on where I should source the vacuum hoses from, and if there are any other issues I should look after while it is partially dismantled?

 

This appears to be the culprit, or one of many. I assume this is the EGR solenoid, and the end of this hose connects to the EGR valve. It got brittle, and fell off when touched.

 

Glad that you’ve found the possible reason. It is always like that – the most important is to find the cause, and then it is just the repairment of what’s left. The same was with the car lights in my old car. One day they suddenly stopped working, and I could not understand why. I was looking for the cause for more than four hours in a row, and then I finally got it – a small contact that went loose. This small thing cost me four hours of my time. I envy some professionals' ability to understand the problem by just looking at the car. I need a skill like this.