Shortly after buying this car we got a notice from Volvo about a firmware upgrade and took it Volvo of Houston for the free upgrade. Seems that right after that all these problems started: check engine light came on, indicated O2 sensor..cleared code(s), changed both sensors, code came back. Returned and replaced sensors..same code again. Now getting brake light, check engine light, flashing yellow arrow light ( all intermittenly ) sometimes the speedometer stops working and the display disappears then suddenly starts working again. Took it to local import mechanic who said his equipment could not "talk" to the computer ( only seeing O2 codes ) he said he works on Volvo normally and not sure why equipment cant communicate. He suggested taking to Volvo dealer.. I called and explained to a service rep what was going on and he says it is probably the ABS system causing the problems but it will cost $120.00 for diagnostics. I've already paid for diagnostics at Volvo of Houston, and the import mechanic. I think its time to talk to the real-world experts who may have experienced the same pain. Any ideas/help would be greatly appreciated. I hope I've included enough info..if not please let me know what other info may be needed. THANK YOU THANK YOU THANK YOU !!

 

well that sounds like a CAN network issue. check the fuses. if nothing then i would think the abs module is shot, not uncommon. i think the dealer will need to replace it and download it, i know you can try a junk yard one but it a 50/50 shot of being good or not.
and of course if you do this and it doesn't work it isn't my fault. the absolute best way to fix this is go to a dealership you trust for volvo and have them diagnos it.

crush

 

Thanks for the input ! Appreciate your time ! What is a CAN network ?

 

I'm having the exact same issues on my 99 V70 right now- going to the dealer tomorrow so i'll let you know what i find out. Did you by chance get the firmware upgrade around last summer?

Most of my research of similar symptoms has led me to believe a bad ABS module-old thread below with link to matthews volvo site for DIY repair

https://volvoforums.com/forum/volvo-...-repair-15635/

 

What did you find from dealer?

 

Bad ABS Module- wanted $375, but you can do it yourself its very easy and parts are pretty abundant- could do it for $50-75

I also had codes:

ECM-530D faulty signal from TCM
ECM-510F and CDM-0001 Vehicle speed signal missing