2006 XC90 2.5T - intermittent start issue

Guitarded · Post by **Guitarded** » 23 May 2025, 09:37

Help!

We've had our 2006 XC90 for about 12 years now. Over 350,000km and it's been fantastic.

But over the past couple of months, it has developed a no start issue.

Every now and then, it will not start. It will crank and crank, engine turning over strong, but just won't start.

I turn the key off, try again, and it will crank strong again, but no start.

If I repeat this two or three time, it will eventually start like normal, idle normally, and then we go a week or two with no problems.

Doesn't seem to be affected by fuel level or temperature - either engine temp or ambient.

I'm thinking injectors or maybe a fuel pump? But I'm no expert.

Thoughts?

Thanks.

Post by **ggleavitt** » 23 May 2025, 09:57

Best to get the vehicle coded. If flaky pump, you also have a PEM module driving the pump and for MY 06 I think it's still external. Might be good to have a quick look at the PEM, it should be under the right side of the vehicle next to your fuel filter, close to the rear wheel.

Pump is absolutely a suspect, PEM is an easy thing to check and omit. Thread on PEM location and alternate PNs here: https://www.swedespeed.com/threads/xc90 ... on.588547/

Vova585 · Post by **Vova585** » 23 May 2025, 11:52

Agree with above. I would suspect fuel delivery at this time. Car runs good when started-so compression is likely decent.
https://volvoforums.com/forum/volvo-xc9 ... ial-71534/

Find your PEM and look for obvious signs of corrosion/damage as they show. If that all looks pristine- buy https://www.amazon.com/Nilight-Pressure ... 0DER&gQT=1 or similar not complicated fuel pressure tester. On 2.5 engines you have a pressure test port on the right side of the fuel rail. After the first signs that car is not starting(you want to diagnose and not guess) remove blue cap, connector tester(shrader valve). Prime the pump 2 times(key off to II position) and see what the pressure is(if no pressure or below 0.5 bar after priming and e gine off- fuel delivery is your issue(fuel pump, pem, connection). Usually the pressure should be around 3 bar when you priming the system and when engine running. Any unusual sounds from fuel pump when it works? If you have scanner or ability to read codes it would be great as well. Sometimes misreading fuel pressure sensor is a cause of the issue.
Credit to Ivan from PHAD if you want to understand this system more

Guitarded · Post by **Guitarded** » 26 May 2025, 10:43

Thanks guys! Investigating further today.

Guitarded · Post by **Guitarded** » 26 May 2025, 10:53

Oh, and when scanned, there are only two codes.

P0101 - mass or volume air flow A circuit range/performance
P0116 - Engine coolant temp sensor 1 circuit range/performance

Post by **abscate** » 27 May 2025, 04:09

Clear the codes and see if they come back. If the coolant temperature sensor faults, the cold injection amount won’t be right and it won’t start. It will like start and run fine when warm.

Use the fuel pressure measurement to diagnose fuel delivery problem from the coolant sensor

Guitarded · Post by **Guitarded** » 09 Jun 2025, 13:08

abscate wrote: ↑27 May 2025, 04:09 Clear the codes and see if they come back. If the coolant temperature sensor faults, the cold injection amount won’t be right and it won’t start. It will like start and run fine when warm.

Use the fuel pressure measurement to diagnose fuel delivery problem from the coolant sensor

The codes always come back after being cleared.

I love these internittant issues. Haven't had an issue since just before starting this thread. Literally once every few weeks.

There's an XC90 that just arrived at the local Pick N Pull. I'm going to go pull the PEM off it and see what happens. For $20, it's worth trying that first. And I should probably just repair the termp sensor anyway.