I’m getting intermittent CEL on my 2001 V40. It always happens the same way:

I’ll be coasting downhill – usually at a fairly low speed (<50 mph) and the CEL comes on. When it is on, the car seems to have sluggish acceleration. I’ll drive it for several days and then one time I’ll start it and the CEL will be off. Several days later, the sequence repeats itself.

I’ve had the codes read several times – it comes up P101 which points to the MAF sensor. I’ve cleaned the MAF and this seemed to solve the problem but then it returned.

Someone on this forum suggested that if may be an intake system leak. I disconnected the intake just downstream from the MAF, made a plug and blew in smoke with a bicycle pump. I was not able to see and smoke escaping anywhere and the plug blew out at about 10 psi.

I had an independent shop read the code (when the light wasn’t on) and it came back as ECM-14 MAF sensor – faulty signal. DTC is found but status unknown.

A week later I had the car at the dealer for an unrelated matter and they read the code when the light was on. It came back ECM-25 Long-term fuel trim – Lean. DTC is found but status unknown.

I then replaced the MAF with a brand-new VDO (OEM) unit. The problem went away for about 900 miles but is now back with the same regularity.

Any clues as to what might be wrong?

Thanks - John

 

Check for a vacuum leak somewhere in the system.