how does one know if there vehicle has an ecu problem? what are the symptoms that an ecu gives especially the pink ecu that some volvos have? I'am gone to check this weekend to see if my 1989 245dl has a pink ecu, for car acts like it has gremlins sometimes

If you've a mind to do an ECU susbstitution - among my ECU collection (all available) I have a pink label 561 that came from a good running '89 740 - yours for $10 plus postage--$11 USPriority. Call me at 631-968-8933 or write--fastforwardphotoATyahooDOTcom -- Dave

Also, read the ECU codes (if any), that may provide a clue for other grizzled brickaholics.

jorrell
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92 245 307K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

LH2.4 activates the fuel pumps for a second or two even if you just turn the key to on. On an '89, the telltale is no pumps running. If you kneel on the ground by your driver's door and hit the key, you should hear the main pump easily.

If you don't, first thing to do is pull the felt under the dash on the passenger side. When you key the ignition, you should hear the relay click in. If it doesn't, get a meter and check for power and ground at the relay. This is what Dan was talking about. The ECU completes the circuit to the relay. If you have power and ground when you hit the key, the relay may be bad, which is a quick fix.

If you determine that the relay is working, check the main fuse in the engine bay to make sure you have power going to the relay for the pumps (large, red wire). Check the plug at the relay and make sure you have power at the heavy wire there too. Next step is to check for power out of the relay. That should be the yellow/re wire, or the heaviest one (I'm pretty sure it's YR) that goes to the fuse panel. When the relay closes it powers that fuse. If the circuits are sound and the relay is good, but no pumps, your problem may be a dead main pump.

I have seen two 89s over the years that have the fuel pump relay rewired rather than replace the ECU circuit.

If it's an '89 pink label, I'll bet it's the ECU. I believe it's a power transistor in the ECU that dies.
DS

could ecu problems come and go or is it something that once it happens it stays until repaired

Hi. The key to determining what's wrong relies on some patience and the use of a voltage meter, in my opinion. Art Benstein was was kind enough to provide me with the following link for more information on ECUs.

http://www.brickboard.com/RWD/volvo-990665.html

Art also informed me that the culprit in the 561 failures is not a power transistor, but a chip, so my apologies for that bit of misinformation.

As to replacements, white label 561s are generally accepted to have the fix for the problem. You can also substitute 933 units (with EGR), 935 and 951.

Good luck!
DS

If the issue is intermittent, it is 99% most likely NOT the ECU. High up on the list is the fuel pump relay and a corroded 25 Amp fuse/holder on the inner fender well on the driver side.

jorrell
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92 245 307K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

I have replaced the 25 amp fuse underhood and relay plus cleaned battery post still have intermiten problem

Then I would recommend unplugging the ECU harness from the ECU and looking for corrosion, especially if you have a water/rain leak on the passenger side front foot well. Once unplugged, also check for pins in the harness connector that have "unlocked" and slipped back, ie. they will appear to be short compared to the rest of the pins.

jorrell
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92 245 307K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

Usually the pink label fails by losing the ground through the ECU to the Fuel system relay causing a no start.
Dan