99' S70, 5-speed, Immobilizer Problem. End of the road for Matilda?

Post by **850 LPT** » 24 Apr 2023, 13:09

Hello everyone,

The problem started a few months ago when the car occasionally cut out going over bumps, and the final time it actually died going over a bad stretch of road. It started back up, but I only managed to drive it to a church parking lot. It would start again but I didn’t trust that it would bring me home. While it was sitting there, I installed a new fuel pump relay which of course did nothing. It was still cutting out badly at random times even while idling.

Next was a tow to my favorite indie. I accompanied the trip and was able to move the car to a parking spot across from his bay, it was after hours.

The next day he called me because he couldn’t start the car. Full power everywhere, but no crank. Then he started checking things out and found that he could not read anything from the ECU. Vida was not able to establish any kind of communication except to the instrument cluster.

He determined that the ECU needed to be rebuilt and send it to XeMoDex. It came back and he re- installed it. And nothing! He then installed a new antenna ring but negative. After that he examined the wiring to the immobilizer but everything checked out ok.
His assessment at this point is that the immobilizer is dead. I don’t really have an opinion on this but it sounds very plausible. Sounds like if there is no communication with the ECU, and with that we have a no start situation as witnessed.

I am exploring two avenues to get the car running again, but I really need the input of you experts.
My mechanic tells me that he can program a NEW immobilizer, but they are NLA at the dealers. Maybe I can find old stock somewhere, we shall see.

There might be another option, but this is just me guessing. Maybe I can find a used immobilizer WITH a matching key. If I can, I could take the chip out of that key and glue it next to the antenna ring, and then take the chip out of my original key so it doesn’t interfere.

I told my mechanic this and he wasn’t sure if the immobilizer is somehow encrypted to the ECU, in which case this would not work.

I am at the end of the rope on this and need your help. If I can’t figure this out the last option is to part the car out, which is an unbearable thought.

Thanks in advance for your insight,

Dirk

dikidera · Post by **dikidera** » 24 Apr 2023, 13:36

Ok so...my S60 2005 has a bad ignition key lock. While the car is running I can remove the ignition key. My car definitely didn't die.

Post by **abscate** » 24 Apr 2023, 19:28

I believe in 1999 the ECU, immobilizer, and display module are all VIN pinned

Post by **scot850** » 24 Apr 2023, 19:35

The ECU is read through the DIM/speedo cluster. If you can't see the ECU, it could be an issue with the cluster. Are your dashboard mounts good? If it is moving, it may have dislodged the connector on the speedo. Only way to check is to remove the dash top and check the connectors are all good. If you swapped the speedo cluster out at anytime, and it came from a different car, Vida will not be able to read the ECU, or TCU on an automatic.

A worn electrical portion on the ignition key will also cause strange issues, but I don't expect it to cause issues with reading the ECU.

Neil.

Post by **abscate** » 25 Apr 2023, 03:27

See Volvooh thread here! He finally diagnosed with watching VIDA during failure

viewtopic.php?t=82157

Post by **850 LPT** » 25 Apr 2023, 05:42

scot850 wrote: 24 Apr 2023, 19:35 The ECU is read through the DIM/speedo cluster. If you can't see the ECU, it could be an issue with the cluster. Are your dashboard mounts good? If it is moving, it may have dislodged the connector on the speedo. Only way to check is to remove the dash top and check the connectors are all good. If you swapped the speedo cluster out at anytime, and it came from a different car, Vida will not be able to read the ECU, or TCU on an automatic.

A worn electrical portion on the ignition key will also cause strange issues, but I don't expect it to cause issues with reading the ECU.

Neil.

Thanks Neil, this is really helpful information. Never knew any of this. My cluster is original to the car. It only came out once after bought the car to replace the bulbs. Never had a problem with it. Also, my dash is surprisingly tight, with no rattles or squeaks.
Maybe I should mention this to my indie mechanic, but that's a tricky conversation to have.

Dirk

Post by **850 LPT** » 25 Apr 2023, 05:51

abscate wrote: 24 Apr 2023, 19:28 I believe in 1999 the ECU, immobilizer, and display module are all VIN pinned

Thanks Steve, so this means for my testing idea I would need to change out the display and ECU as well. I would need a stick shift ECU, but for testing an automatic ECU would probably work.

Dirk

Post by **abscate** » 25 Apr 2023, 05:57

I have all three in a box with a key too, but in the middle of a move. Get her home safe in the driveway and let’s tackle it together

Post by **850 LPT** » 25 Apr 2023, 07:43

abscate wrote: 25 Apr 2023, 05:57 I have all three in a box with a key too, but in the middle of a move. Get her home safe in the driveway and let’s tackle it together

I will take you up on it, thank you Steve. So I wonder if I should bring the car home because that means another tow. But that may just be the best option right now.

Dirk

Post by **volvolugnut** » 25 Apr 2023, 09:12

There appears to be emulators available for some Volvos to replace some parts when there is no start. I used an emulator to repair my Mercedes with an Electronic Ignition Switch problem. I had to do a lot of research to find information and a source in the US that I trusted.
volvolugnut