I have an 89 740 non-turbo. It wouldn't start the other day and after some extensive forum searching, I suspect the culprit is the crank position sensor. I would like to verify this prior to spending the $60, though. I found a thread on checking for codes with the diagnostic connector, however, the connector in this car has no LED light, no button to push and no little attached probe. Is this connector simply broken or is there a reason for those items to be absent on this car? Can I swap out the connector for a good used one? Anybody got one?

dave

 

Go to www.stepbystepvolvo.com. If no-start, pull fuse tray out and use "naked" fuel injection relay to determine if the crank position sensor is dead. You'll understand once you download 740 no-start guide. If EM2 does not close on ignition "Start," then most likely you have a faulty CPS (or broken wire leading to it). I've never done this on the LH-2.4 system, but suspect it is not different from the LH-2.2 system. You also want to check for correct voltages for feed into the CPS. Let me know if this helps.

 

I swapped the diagnostic connector from our 91 240 in to the 89 740 and checked codes; got 1-1-1. I suspected the crank sensor so I pulled it out to look at it. It was very oily and dirty. I wiped it off real well and put it back. Started up and ran, stumbled some, I think it was flooded from trying to start it so many times. I even found a connection for the vacuum line for the cruise control. Drove around the mile, it ran good and the cruise worked! So it's been a good day. I know cruise is no big deal, but we're planning on driving that car to San Antonio to my son's boot camp graduation in April: cruise will be a big deal then.

Dave

 

Do yourself a favour and carry a good used crank sensor in the car.
Once they start getting flaky, they're on their last legs.

Regards, Andrew.