I had been experiencing a soft brake pedal and the rear drivers brake wasn't working (see prior post).

I visited the scrap yard/auto recycler and bought a "new to me" brake master cylinder and abs unit. I installed everything and the pedal is now hard and all four calipers are working, BUT THE CAR WILL NOT START… I GET A WARNING SIGN “immobilizer see manual”

It appears that the main computer looks at the abs serial number and if it is different from the original it won’t start the car…. What do I do to correct this?

Any help would be greatly appreciated.

 

as an easy / don't expect it to work thing, you can try disconnecting the battery again for 30 minutes (to let residual capacitance to drain) then reconnect and try to start up. Also try locking/unlocking the doors 5x with the fob to see if that resets the immobilizer.

 

Update


I found some info online that confirmed that the main computer in the car talks to the abs and as the serial number on the new/used ABS is different from the original serial number the main computer will not allow the car to start. The main computer needs to be re-programed to accept the new abs serial number.

I have a local garage that specializes in Volvo’s and Saab’s so I talked with them to see if they could re-program my computer. They informed me that it has to be done at the dealer and that the dealer will rip me off. Lovely…

The abs unit consists of three main sections, one section is the electronics and that section contains the electronic serial number.

I took the old abs unit apart

I took the new to me abs unit apart

I put the original electronic part on the new to me abs unit and put it in the car.

WOW it appears to have worked, the car will now start and the brakes are working with no abs light.

Now onto the suspension noise. I may be posting another question about that.

 

Well played! I've been considering doing the same for my SCL (Steering Column Lock) module, though it doesn't look like it would be easy to replace just the electronics bit - and a failure to get it right would result in not only a trip to the dealership, but a tow there!

BTW, I think it's astonishing that Volvo would go to the trouble of coding an ABS module to the car... makes no sense to me.