P01010A MAF Error XJ8

[anonymous-user]

HI All. I have this P01010 code coming up with monotonous regularity on my 2003 4.2 XJ8, relating to the MAF reading being out of range. I've checked the inlet for leaks and cannot see any, and I've cleaned the MAF with the correct cleaner. The garage said that it put the light on before I bought it and he swapped a "known good" MAF from another car into it.

My freeze frame data is

Vehicle Speed: 36mph
Engine Speed: 1578rpm
Throttle Position: 10%
MAF air flow rate: 14.83g/sec
Intake MAP: 39kPa
Fuel Pressure: 387kPa
Short term fuel trim bank 1: -2.34375%
Long term fuel trim bank 1: -2.34375% (suspiciously identical)
Short term fuel % trim bank 2: -0.78125%
Long term fuel trim bank 2: -3.125%
Engine coolant temp: 89C
Timing advance 42 degrees


Which all looks perfectly sane to me, I'd expect about 14.83g a sec air flow with those parameters. Fuel trims don't suggest an air leak either, if I'm understanding them correctly? Does anyone have any bright ideas?!

[GreenV8S]

dme123 said:

The garage said that it put the light on before I bought it

Do you have any warranty?

[anonymous-user]

GreenV8S said:

Do you have any warranty?

Yes but the warranty is in Leeds and the car is in Cardiff. I also have reasonable expectations about how much a warranty on a 15 year old 150,000 mile Jaguar is likely to be worth

[GreenV8S]

dme123 said:

P01010 code

Is it P0101 or P01010?

This page describes some common causes for the former: https://www.samarins.com/diagnose/p0101.html

[anonymous-user]

GreenV8S said:

Is it P0101 or P01010?

This page describes some common causes for the former: https://www.samarins.com/diagnose/p0101.html

It's a P0101, I think this app has appended something.

It runs perfectly and on resetting the code it merrily continues and won't come back for a while. Only seems to do it dawdling in city traffic at 20 - 40mph.

I've also noticed that if I blip it at idle the revs will drop below idle and it'll stumble briefly before getting back to normal. I'm wondering about a slightly stuck open EGR valve given the negative fuel trims, or a dirty inlet gumming up the throttle.

[GreenV8S]

I guess it must be either some reading fractionally out of spec under those particular conditions, or a transient glitch. Both seem likely to be difficult to diagnose without a sound understanding and some specialised test equipment. On that basis I think you need to either find (and pay) an expert, or put in the time to become an expert yourself.

[stevieturbo]

Freeze frame means little. Although long term fuel trims being ok may be useful.

"Known good"...could really mean anything. Is the MAF currently an OEM part, or aftermarket ? Lots of aftermarket stuff really is just rubbish.

[anonymous-user]

stevieturbo said:

Freeze frame means little. Although long term fuel trims being ok may be useful.

"Known good"...could really mean anything. Is the MAF currently an OEM part, or aftermarket ? Lots of aftermarket stuff really is just rubbish.

It's a Denso part. I might pick up a new one, at 150k I don't mind chucking parts at the car as they've probably all 80% fked anyway!