2006 XC70 Immobilizer

[malcolmtent]

I'm having what I think is an immobilizer issue with my 2006 XC70. I'll start from the beginning.

2 weeks ago, I tried to start my car and I couldn't turn the key past the Accessory position. I could, and still can, take it out of steering lock. But I couldn't put it in neutral to push it out of the way – it was blocking other cars in a driveway. So AAA towed it to my mechanic's shop.

My mechanic took the cable off the shift-lock override, and took the ignition lock apart – meaning that the part with the tumblers is still in the steering column, and the round white switch was hanging loose. He put the key in the tumbler part and a screwdriver in the white part, and she started up just fine.

And I use this set up for a day or two until I stop to put gas in, and when I get back in, the car is immobilized. Some internet research reveals that “lock the door 5 times with the remote” trick, and after a dozen attempts, I get this to work and the car starts again. But it's not quite right – I have no cabin heater, heated seats or radio.

At the repair shop, we discover that my battery is low, so it gets charged. He didn't have time to disassemble the tumbler part or investigate further, so I drive off. Then I get a warning light saying that the car has no oil pressure, so I pull over. The car gave me this once before, and it was bogus. I listen to the engine and there's no rattling sound, so I continue another couple of miles, and I notice that I do indeed now have a rattling sound. So I park the car thinking I've got a blown engine.

The mechanic comes by with a jump pack, and we can't get it out of immobilize mode. Sometime,s, the 5x lock trick gets the immobilizer message to go away, but she still won't crank. All kinds of red warning lights are coming on – air bag failure, brake failure. Once in a while, we get a mini-crank out of her before she goes right back to immobilized.

The next day, we come back with a fresh battery, thinking that mine is probably shot. It's 4 years old, and we have 10 degree weather here, so it's likely that the existing battery is indeed useless.

And she starts up after a couple of lock-the-door-5x cycles !!

At first, the engine sounds normal. No rattling at all. But after a minute or two at idle, the rattlin returns, which the mechanic claims to recognize as a crankshaft timing issue. He's also adamant that I have oil pressure. So we drive the car 10 miles to his shop again, and the oil pressure warning light comes on again, but the car makes it there without getting any worse, so I have to believe there is indeed engine oil pressure or the the engine would have seized.

After several days at the shop, we still haven't got the engine restarted. The usual suspects have been checked – fuses, connections to the computer, starter motor wires. We've let the car sit 5 hours after start attempts. We've hot-wired the starter motor, and it cranks, but it won't fire up.

The mechanic has put his test box in the computer, and he's getting a message saying that it is 'Start Prevented'.

I still haven't fixed the ignition lock problem, so we're trying all of this with the ignition in 2 pieces – the key going into the tumblers on the steering column and a screwdriver being used to turn the swtich itself. I'm poor enough that $25 for a pressure sender unit is an issue right now, so I'm reluctant to pay for a new ignition switch if I can't prove the car to be viable. And certainly, taking to car to Volvo is completely out of the question.

What do we try next?

Thanks a lot....