s80 hard start when warm crank position code + srs light
 

ok guys i got my Volvo s80 back together after a head job and now it acts like it doesn't want to start. it starts fine when cold but after it been warmed up it turns over a lot before it fires, and now its throwing a crank position code. iam stumped i dont think i need a new crank sensor. to top it all off i got a airbag light on and it has not been wrecked. can someone shed some light on this issue or point me on the right path thanks

Few things could be causing the crank sensor code.

Bad\missing earth cable after doing the head job
VVT set incorrectly
Starter cable needs to be re-routed.

In my case it was the latter of the three. I had to re-route the red power cable going to the starter motor around the outside of the PCV pipe to stop it interfering with the crank sensor signal. Tell tale sign of this is that the tacho will fluctuate while you turn the motor over.

but it only does it when warm? starts great when cold

Its possible that the timing is out in a manner that makes it hard to start warm and normal when cold. Think about the variables brought in as the result of a head job: Valve timing and grounding. Yeah, it could be an actual crank sensor issue too, but less likely to be honest. If the tacho holds a prettty steady 300RPM while cranking its probably not the sensor.

On the SRS light does an SRS Service message come up in the message center?

A spike in the electrical system can set off the SRS light. I did it myself once by unplugging the radio with the battery still connected. When I had problem with the Anti Lock Brake (ABS) module it also set it off. This is why they tell you on this car before working on anything electrical, disconnect the battery.

You will need to find someone with a Volvo or BSR tool which can access the body codes to reset it. The conventional engine scanner will not clear this light.

Good luck with the cranking problem.

Where are you located?

yes srs is in message center. going to go ahead and reline cams. this car has been a bitch nothing has been easy on it my first Volvo and hopefully my last and my location is mooresville nc 20mile out side of Charlotte

You're too far from NYC for me to help with my scanner :)