Fault Code Explanations

Hi All,

Just a quick question on the explanation of fault code. Done a search, and have found lists of them, but the description seems to be the same as I get from the faultmate.

2000MY v8 on lpg.

She's been running a bit rough, and I suspected MAF as similar symptoms that I had a year or so back, fine under acceleration, but 'jumpy' when off throttle. Previously she stalled whenever I got to a junction, but not done that this time (yet!). Fault codes seem to confirm this diagnosis.

Anyhoo, last time I put a cheerful cheapy from the bay on her, as it was a third of the price of OEM, and I was happy to change earlier if it worked. It's done 30K miles happily, so no issues with replacing it with the same. However, I thought I'd look to island, who, on all their complete MAF units (but interestingly NOT the sensor on its own) state that they aren't suitable for LPG due to risk of backfire and invalidating the warranty.

I'm assuming this is just to cover themselves/the manufacturer against this, rather than the MAF not actually working with LPG.

Attached is photo of faultmate, with the MAF error, and also a transmission error, which I can't make head nor tail of (one of the symptoms is revs dropping, and then picking up again as she changes gear, so though I'd better check for codes in there).

Questions are (got there eventually!):
What does the MAF 'Drive Cycle A' actually mean?

On the second photo, the transmission fault code, should I be worried, what does it mean, and what can I do to fix?

Does anyone know where I can find a list of fault code explanations? (not expecting a full story, as I know the codes only point to stuff, but something more than the faultmate description would be good )

All codes were reset this morning, and then re-appeared after driving home from work (approx 45 miles).

Cheers

Marc

According to the Faultmate P0102 is MAF signal to high. Which would mean signal is high, over max range. But according to Land rover P0102 is MAF circuit low input. Can't find anything for box.

The maf fault is possibly because the cheapo maf reacted differently than the engine ecu would have seen from a proper one,(They were not that expensive from Bosch or LR,but cant say I've bought any for a couple of years) fitting a decent one will probably make the error go away.
The can fault is most likely just low battery voltage on start up,or because of the implausible reading from the maf.The engine and gearbox ecu's chat to each other,(Only those two ecu's are connected by it on this car) on a twisted pair of wires,can high and can low.The normal protocol is for the ecu to send each message 5 times,if it doesnt get sent properly it will log a fault.The ecu will then try again,often successfully so there is no problem.But if the ecu doesnt have good info to work with it wont send a response to the other ecu which is expecting it,again an excuse to log a fault.
Most can bus faults can be cleared and ignored,they are only a problem if there is a persistent issue which often will be recognised by the driver.

Cheers Guys.

I think the cheapo MAF just hasn't lasted as long as the original, but like I say, £33ish against £120ish, so worth replacing each year if it works in the meantime

Although I can't say for 100% when the MAf fault appeared, I have looked at the fault codes in the last year or so, and it wasn't present when I previously checked (just can't remember when that was!)

Hopefully, as you say 8inaV, the can fault will be related to the MAF fault and will go away with the new MAF.

fingers crossed......will report back when new MAF arrives...

MAF and LPG - single point systems introduce the gas via a ring in the induction pipe, if the engine revs drop quickly, or gas pressure is too low they can backfire through the intake pipe work and damage the MAF. It is common to fit a backfire valve (often referred to as a fart flap) in the pipe work to protect the MAF.

Multipoint systems aren't affected.

Sorry, should've said its a multipoint, so I guess no issues on that then (although I'd quite like a fart flap!!!)