2006 Volvo XC90 starts intermittently

Question

I have a 2006 XC90 2.5T with about 70k miles on it, almost 2 years ago it just would not start, wont even crank when turning the key...displays a message that says "Start prevented, try again" Here are the steps that I have already taken:

1) replaced antenna ring with OEM 2) have checked all fuses and relays 3) have replaced the battery 4) scanned with OBDII scanner and cleared any codes

when the OBDII was ran, it said low voltage to ignition so thats when I replaced the battery all together cause I figured it had been sitting for a while with only being started a few times. I try to start it often, a few times it has but once I shut it off its bye bye for a while. Another fact to mention, the vehicle only came with the valet key and I do not want to pay $500.00 for a new key from Volvo. I just want my car to be working again but cant afford big repair bills to get it up and running again. Any ideas or suggestions would be appreciated.

Thank you

Answer 1

I only know of immobilizer related stuff so this is all I will address but the intermittent "starting disabled" could be do to a lot of things not just the immobilizer. You really need a good diagnostic tool to really dig in. If you know a good mechanic or hobbyist and get your hands on a j2534 tool then you can get a 3 day subscription to VIDA (volvo's software) and do some good diagnosing. I would recommend you get downloads with the subscription so you can update some modules or add keys just in case. It will run about $80 + downloads ($30-$60 per module updated).

Here is what I would do: Scan with VIDA and investigate the DTCS. IF its an immobilizer issue this would be my course of action most likely.

1: If there is a bunch of stuff on key ring, remove it all. It may be causing interference between immo antenna and the transponder in key.

2: Check voltage at antenna. if its low then check for shorts.

3: New antenna ring. They commonly fail on older volvo's so its good you have already addressed this.

4: New keys (valet is ok the fobs use the same transponder type anyway) and program them with the vida subscription we have going. The key programming itself is about +$30 (multiple keys ok). The remote programming is another $30 if you want remote keys.

5: I would finish by updating CEM and ECM since I have the subscription going.

6: Clear and scan system again to locate and correct any other dtc's.

Its only efficient if you are good with diagnostics and do as much as possible with the active subscription other wise you may as well just pay someone else to do it all.