Hi, I'm trying to resolve an issue where both Mass or Volume Air Flow circuits (A and B) error codes are being logged (see below for exact codes). I've tried removal and cleaning using a MAF Air Sensor cleaning spray...alas, still get the errors when re-fitted.

If only one circuit error was being logged (i.e. either circuit A OR B) I'd buy a new sensor and fit immediately...but why would BOTH circuits be reporting errors? Is it still possible that only ONE of the sensors are dud? or is it something completely different?

Thank you.

Specific Error Codes:
P0100: Mass or Volume Air flow - Circuit Malfunction
P010A: Mass or Volume Air Flow B Circuit

Car is a 2007 Jaguar XJ, 2.7D.

 

You need to check the circuits for power and ground before replacing parts. Both Brown/Red wires are +12v with the key on. Both Black wires are ground. Wires you can't check without a scope are the White/Blue and White/Red wires which are the MAF signal. The White/Purple wire on MAF sensor 1 is for ambient air intake temp, irrelevant to this error code. Check those power/gnd first. If they are okay, use a scan tool to view live data from MAF1 and MAF2, see what they are reporting at Key On, Engine Off, at idle, and at 2000 rpm.

 

Thanks mhamilton. I've test the MAF sensor harness and successfully tested ground - I can see 5 v being reported on the sensor wires. This is with the Key On.

However there is no power, i.e. the Red/Brown wire on BOTH sensor harnesses are reporting 0.03v - not the +12V expected. I've checked that there is +12v on Fuse 8 in the compartment bay box (that the manual indicates is MAF sensor and others) - there is.

Any suggestions on what to check next...the wire disappears deep into the engine...going to be tricky following it!

 

Well, I had another look at the fuse, it was fine, but I randomly also checked the fuse next to it (Position F8 - Diesel EMS, VBR's, PCV and VCV) and it had blown. I've replaced it and the fault has gone.

Fantastic...but....I'm now getting DPF errors logged. I think this is because due to the above a regen has not happened for a while and it's clogged? I've taken it for a long motorway run in segments of 30 mins+ this afternoon for about 1.5 hours in total. With each stop to clear logs (get out of restricted performance mode)...but errors keep being logged and car enters restricted performance mode.

Any ideas? Thinking of getting it chemically cleaned, it's only £85 if it would help.

Codes:
P2459: Diesel Particulate Filter Regeneration Frequency
P244B: Diesel Particulate Filter Differential Pressure - Too High (Bank 1)
P2453: Diesel Particulate Filter Pressure Sensor A - Circuit Range/Performance

 

I meant Fuse 9 had blown.

 

Glad you found a simple fix! Not sure why the fuse would have blown, I'd keep an eye on it. Hopefully someone with more knowledge on diesels can chime in, I have zero experience with them.

Fuse 9 in the front box (20A) feeds the two MAF sensors and an "Inlet Port Deactivation Solenoid." Not the slightest idea what that solenoid is used for, but if the fuse blew, I'd look at that solenoid and see what it's doing. Unless you have wires chaffing to ground somewhere the 20A fuse shouldn't have blown. Might have something to do with your DPF regen error.