Hi mmchenry,

I'll guess you searched the bb for article containing information on your ECU code issue.

I'll guess your 1991 740 is a four cylinder with the Bosch L-jet? Turbo or no?

Code 2-2-1 is as you say. I have a PDF the 700-900 FAQ here.

Funny, the 1998 printing of the Haynes 240 manual, page 6-2, indicates code 2-2-1 as engine exhaust gases as extremely rich or extremely lean while driving at speed, like highway speeds for some time, I guess. My 700 and 900 manuals are not in reach. Yes, the check engine light illuminates.

Did you check again for additional codes set in your Bosch L-jet ECU? Usually, not always, code 2-2-1 comes after other codes are set corresponding to exhaust gasses being to rich with unburnt fuel. Repeat the diagnostic procedure. Verify you have all accessed all stored codes. I'd also check the codes (socket 6 on the LED tester) to discover if the ignition system has any corresponding codes.

Did this begin immediately or soon after the mechanic replaced the belts?

You may want to further research the fabulous and powerful 700-900 FAQ as well as here on brickboard.

You had a mechanic replace the what belts on your 1991 700 series? Even if a Turbo 700 I doubt any of the air intake has to be removed when replacing all belts on a 1991 740. Can't image it in my head-bulb well enough, so I'm not sure. Not sure with Turbo.

Further describe the change of smell in the passenger cabin when the light goes on. Also, when does this happen? What driving conditions spawn the fault as indicated by the check engine light?

I'd research the FAQ and the Volvo boards for other articles about 700 series with the same Bosch L-jet fault code. See what the articles suggest for remedy.

You can perform a visual inspection of the air intake and vacuum lines. Some solutions may be a missing or broken vacuum line you replace that is old, a leak in the air intake system at a union like a loose clamp or need to re-seat the connection like those at the AMM (or MAF) or throttle body. It could also be that the air intake port (manifold) retaining hardware is sort of loose, yet still snug, (you should check torque on these intake ports once in a great while). If the air intake port retaining hardware is loose for sometime, the gasket between the air intake port and the cylinder head can deteriorate.

I had this same code on my 1991 240. It was well mated with other codes having to do with fuel trim. It turned out it had a slight leak at the exhaust union at the head pipe output to the cat converter input. Repaired the leak at voila, all fixed.

Hope that helps with your diagnostic and troubleshooting efforts.

Questions?

Thanks,

Cheezy MacDuff
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stop the .sig madness!