P1 Platform Immobiliser / SRS issues

So all P1 (C30,C70,S40,V50 etc) suffer from immobiliser issues caused by the electronic Steering column lock failing and also on 2.0D models, lose of immobiliser data from the ECM, also common are SRS modules failures due to low battery voltage.

Let’s talk about the Steering Colum lock (SCL) issues first.

The SCL can fail locked or unlocked, but if it wont talk to the CEM it will prevent he car from starting, so whilst you may be able to turn the wheel, it doesn’t matter because the CEM needs to talk to the SCL to approve starting of the car.

If you unplug or remove the SCL it wont help because the CEM still needs to talk to it.

If buy a brand new SCL and plug it in, it wont help because the virgin SCL is blank for want of a better description and needs to be coded.

If you buy a used SCL it wont help because it will have the Immobiliser data for a different car and start will not be approved by the CEM.

OK, so what can you do to fix it?

  1. if it is still talking to the CEM but the solenoid is stuck, hitting the area of the SCL or hitting it directly can help free the solenoid. It will help for a while, but it needs fixing properly before you get stuck in a carpark at 10pm on Sunday night.
  2. Have it replaced by Volvo (but it may fail again! -expensive and shortsighted IMHO)
  3. Perform an SCL delete with Vdash from d5t5.com. This is the most sensible option as it deletes the need for an SCL from the car 100%. The difficulty is actually getting it done. You will need your CEM pin code (see www.modunlock.com ) and a DiCE unit for the Vdash software to use to perform the SCL delete. You can rent ModUnlock and a DiCE from www.modunlock.com
  4. Here is a guide on how to perform an SCL delete

Ok now lets talk about 2.0D ECM’s loosing the Immobiliser data.

The P1 platform 2.0d looses its Immobiliser data in low voltage conditions. I.e. if the battery is a bit tired and its cold and the car is hard to start as the battery voltage dips the ECM corrupts its memory.

It is entirely ridicules and no car should ever become a lawn ornament because of a tired battery. Volvo should be ashamed of themselves for not recalling them for a software update to fix it.

So what can you do to fix it.

  1. Have the car recovered to Volvo for an ECM reload
  2. Send the ECM and CEM away to a specialist like volvodiagnostics.com
  3. I have a rental kit for this exact situation which can be used to do this repair on your driveway without you having to do a thing but plug in and swtich on the equipment. See here

SRS memory corruption

Just to rub salt in the wound, it is REALLY common to find the SRS module has ALSO become corrupt due the the low voltage situation that corrupted the ECM earlier.

Again, during low voltage conditions the SRS memory becomes corrupt. If you take it to Volvo, they want you to replace the module which costs many many $$$$$.

So what are your options

  1. Go to Volvo and have a new SRS module fitted
  2. Send the module to a specialist (Such as Volvo Diagnostic)
  3. Use Vdash from www.d5t5.com with Dice unit to reprogram the module and bring it back to life. Here is an article they wrote on the subject
  4. I have heard, that the SRS module can be swapped out with a correct model donor. However its really tricky, it has to come from a car with exactly the same options as yours. For instance, if your car has the passenger airbag isolator switch, then the donor unit MUST be from a car with the passenger airbag isolator switch.

Now some of these issue are caused by other factors, P1 platform cars suffer with oxidization on on contacts for the CEM, SRS module and ECM. So it’s always worth cleaning the contacts to see if the problem will go away. Of course take great car not to cause more damage to delicate CEM contacts and always disconnect the battery negative before unplugging anything!

Correct diagnosis can be difficult if you do not have access to Vida.

For correct SCL diagnoses, in Vida go to Diagnostics, vehicle communication, CEM, Parameters, Immobiliser and look at the SCL status. For instance, if it says locked but you can still turn the steering wheel, the solenoid is jammed and tapping it might help.

For the ECM having lost Immobiliser data, in the same place look for CEM- Immobiliser, Engine control module check – Not OK.

SRS corrupt memory has a fault code of SRS-CFFF

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