Brake failure, service transmission, srs airbag, no guages

[Tanh]

When I disconnect the battery I take the key out completely. I'm not sure how keeping the key in pos 2 will change anything. Afterwards to reset the alarm system all that needs to be done is to press the unlock button on the remote 3 times.

As for the scantool issue, I have a cheap Autel MS409 and it's good for code lookup and clearing and basic diagnostics but won't touch SRS functions. It obviously has limitations but costs me less than 100 CAD. If I were you, I'd go with a BSR PPC tool as you can read volvo specific codes and handle SRS functions at a reasonable cost.

To find out what my codes really were I dropped by Jonathan's and used his. That's how I found out they were all communication faults and not necessarily a sensor or unit malfunction. Bad/loose connections, cracked wire or faulty CEM are all real possibilities. I just haven't been able to find it yet. (Haven't been looking too hard now that I know I can still drive in that condition.)

[precopster]

I didn't say to place the key in Pos II when disconnecting. I suggested placing the key in Pos II when RECONNECTING the battery. It's standard Volvo service department procedure and ensures all modules start properly.

Before reconnecting the battery discharge the electrical system by placing the key in Pos II then press the brake pedal or while the negative lead is disconnected you can touch the positive lead with the negative lead. This ensures any residual electrical energy is discharged.

The BSR PPC3 looks like a great unit but VERY expensive; over $500 An Autel EU-702 costs around $145 landed and handles codes in Volvo terminology and resets SRS codes.

[Tanh]

Ok, I stand corrected. Does anybody have anything useful to contribute concerning the op? It seems this issue is becoming more common. In another thread I read that replacing the CEM did alleviate the issue but that's dealer only and worth nearly the purchase price of my car. Can anybody confirm? TIA

[precopster]

The whole point of resetting the battery connection while key is in Pos II is to properly start all the modules. I feel that either there is a bad terminal at the battery here or a bad earth somewhere. Thoroughly check all cables in the trunk and retighten/clean battery terminals, then have the battery checked.