240 Flashing dash (shift indicator) - why?

Going through idle problems on my 91 240 5 spd -- lots of fun -- After checking connections on my AMM (ignition off) and putting it back in, and then clearing codes (2-3-2, and 1-1-3), I notice my shift-arrow indicator flashes when I start the car. The CEL also comes back on (no surprise there), but why is the indicator flashing? Anyone know? I can't seem to find a reference to this little ditty... A/F probs on the 240 seem more beguiling than I would have thought.. AMM or IAC? what's the tell-tale difference? thanks for any help..

(I previously posted w/ "simple AMM test" -- but haven't figured out how to highlight a new post with the same essential issue.. I'm an idiot, what can i say?)

The shift light should have nothing to do with any of that, is it a steady flash? or like intermittent?

crazy0000 said:

The shift light should have nothing to do with any of that, is it a steady flash? or like intermittent?

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Steady .. about 1/sec. However, I found someone who had addressed this on another forum -- and I had disconnected my battery -- in that note, he said:
"The shift indicator light is there only to tell you when to change gear. Usually they give no trouble but if the power supply has been interrupted, eg batterry disconnected, it has to be re-programmed as the control unit memory will be erased.

If this is the case then this is the solution:
Drive the car in each gear (first gear is not necessary) for approximately 8 seconds.
The gear change indicator light will flicker once (0.5 seconds), as each gear is programmed.
NB. " --- Not sure if this holds water, but I'll give it a try.. I felt better at least finding someone who mentioned the same quirk...

The text of the solution is straight out of the owner's manual. Whenever the battery is disconnected the manual shift indicator needs to be reprogrammed, was true on both my 1989 245DL M47 and my 1988 745T M46.

zrubin said:

The text of the solution is straight out of the owner's manual. Whenever the battery is disconnected the manual shift indicator needs to be reprogrammed, was true on both my 1989 245DL M47 and my 1988 745T M46.

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Thanks, Zack -- Hmmm.. Well I tried this a couple times, and it didn't seem to learn.. Not sure what's going on. Any other pointers would be appreciated. Update on the idle problem is I ordered a re-man'd AAM, and also cleaned the throttle body (which was in bad need). Have to wait for the sensor to see if there's improvement on that front. That dang flashing light, though.. bonkers.

The best thing to do with the up shift light is to remove the bulb. End of problem. You don't need to be told when to shift.

/\ This
and especially not at 2300RPMs haha

crazy0000 said:

/\ This
and especially not at 2300RPMs haha

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Yep.. can't argue with that. thx

mass_mark said:

Yep.. can't argue with that. thx

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For completion's sake (also posted under 'AMM simple test')..:
Flashing shifter light corrected itself (with the CEL reset) when I put in a new AMM --
I got a remanufactured AMM online (discount auto parts) for $220, and put it in. CEL went off immediately, as did the weird flashing shifter lite, which was cool, and the idle is better -- though not perfect. I'm driving it around to see if there's some learning going on, but it certainly seemed to improve things somewhat. Since I had cleaned the throttle body, and checked the O2 sensor, I'm now thinking the only think left is the IAC valve, which I may also clean/replace. I'll report back as things get even better.
thx for the help, volvo-ites.. -mark

For completion's sake.. My stupid idle problem turned out to be due to a mis-oriented flywheel done with the manual transmission/clutch install - I never suspected this at all, until I eventually checked the timing (which was advanced 57 deg!), and then was alerted that these can be put on wrong. Idle's like a charm now. It MAY have needed a new AMM too, but I expect not.
It's unlikely to happen to others, but thought I'd post the resolution of my idle woes for completeness. thnx for the help. -mark