XC70 (P2) - Enigne stutters at cold start and going into emergency mode while driving

[Deevolvo]

Hello Volvo experts,

It seems that here are better Volvo experts than in other Volvo forums in the www, so i hope that you can help me with the following problem as well.

My XC70 year 04/2006 (Diesel - D5 - AWD - 185 hp - 2400 cm³) jerks/stutters in cold start like the engine would go out at any time. After about 10 seconds it settles down and continues to run normally and that's even in pleasant outside temperatures! Once the engine is warm this problem does not exist, only with the next cold start it is coming back.

To the second error/problem, during normal driving and no matter at what speed, the engine sometimes goes into the emergency mode while accelerating. If you just keep driving, the engine suddenly comes back from emergency mode after a few seconds/minutes and accelerates as usual.

I have already had the following components replaced, but without success: RPM controller, mass air flow sensor, EGR valve and swirl flap actuator.

When reading out the error code (also by the garage), the message says "mass air flow sensor faulty". If this error is deleted, it ends up in the error memory again at the next emergency run.

Have you had a similar experience or can you tell me what else can cause this behavior?

Looking forward for your experiences and replies.

[br0dy519]

I'm severely unfamiliar with the diesel variant of these vehicles. But this sounds similar to my issues last year in my petrol 04 xc70 which were

1) Vacuum leaks (like I quite literally had to replace all rubber and plastic in the engine bay)
2) Defective throttle body.

[scot850]

I am also unfamiliar with the diesel motors as we don't get them here. But I would expect they have a coolant temperature sensor. I would have this checked for operation as a bad one will cause issues on cold starts.

Brody also suggested the throttle control which can be an issue on petrol engines we are more familiar with with the limp mode issue.

Finally I would be looking at:

1) Diesel injectors - Does one leak or do they need a good clean?
2) Glow plugs - do they need to be replaced at this age?
3) Fuel pressure

Neil.

[jonesg]

try keying the ignition on a few times before cranking the engine,
if fuel pressure is leaking overnite this will build fuel pressure at the rail for easier starting.