2000 V70 will not start - Immobilizer Control Module Fault

[norcalturtledad]

Hello everyone, hope everyone is doing well. I have a 2000 V70 (non-turbo), @ 155K miles which has been in a shop unable to start. It all started with check engine and rough starts at first, which I suspected was the MAF. With that replaced, the car started to die after ignition, which freaked me out - I was able to get it started and to a Volvo mechanic shop, where it has been *not starting* for a while.

We tried programming a new key and the car did not start still, but did throw an immobilizer error code (IMM-234) and IMM-321 from ECM. He suspected that it was the immobilizer, and with the new key and error code now, we are sure. I did read in another thread that someone had success by disconnecting the battery for 10 minutes, and will suggest that on Monday. Otherwise, is my only option at this point to get a donor car and swap the immobilizer control module, key, and ECM? I am trying to be prudent but just recently did struts, timing belt and water pump, would hate to scrap the car.

[xanthefin]

Incorrect start can trigger Key - Transponder not responding too so it can be fluke code.

With IMMO best not look fault codes but Live Data.


As of you i would unplug that new MAF and turn ignition on and then just look if IMMO and ECM signal is OK as then can Transponder being OK too then you know problem is on ECM side with MAF as example or fuel pump being bad can too trigger IMMO fault codes because of incorrect start or stalls trigger not correct fault codes sometimes.

But to say directly another term key chip fault code then in return too can trigger ECM signal not being OK as IMMO says "Nope" because of the wrong chip.


I want say Antenna is way more likely getting broken than chip in the key but i have discovered master key chip being slightly "lazier" to read with external programmer after many decades but it worked still though fine in the car.

P.S. If you take antenna out of barrel.. put it just then back as you end up fighting ghosts as antenna requires that blob of ignition metal to read the key. Its on 70 Series roughly 5 Ohms if want measure antenna in resistance.

[scot850]

xanthefin has said what I would suggest as well. Do you have 2 keys? If so, try another key.

Battery disconnect of both leads, touch them together and drain any residual power from the system.

Reconnect the battery. Does your immobilizer chirp when the -ve cable is connected with +ve already connected? Does the alarm go off when you do this?

Try locking/unlocking the door 2-3 times manually with the key in the driver's door lock. These systems as mentioned, can get confused.

If that does not make a difference, then the next simple check is to remove the antenna ring from around the ignition key barrel. There is a little tab that will likely break on the side nearest the steering wheel but not a concern. If it works, the column cover will hold it in place.

Disconnect the connector and clean with contact cleaner both sides of the connector and cable end.

Check the inside of the antenna for cracks. If it is cracked you will need a replacement, junkyard or dealer.

If that all fails then we need to dig in further to the stuff xanthefin mentions. If the car worked before it was worked on, it was something in that process that has caused this.

Neil.