406oc.co.uk

My wife has a 1999 406HDI estate which has covered 198K miles. she has owned it since Dec 2005. It ran with no problems at all (aircon never worked though!) until last summer, when it was off the road for a couple of months (non-starter, "Electronic Ignition Fault"). Neither the local main dealer nor the nearby auto electrician could really pinpoint the fault, to cut a long story short we had the immobiliser programmed out of the ECU, that didn't cure it, we then fiddled about with the connector for the relay next to the ECU and it came back to life and seemed to run normally. The immobiliser light stays on as expected, also "Electronic Ignition Fault" is displayed for 15 secs. on starting.
After a longish run before Christmas there was a sudden and quite noticeable loss of power, and the engine management light now comes on intermittently. Top speed is 60-70mph depending on gradient, but can suddenly drop by 10-15mph. After a few minutes it recovers - at least to its usual 60-70 max. It's painfully slow on hills. A few days ago I was sat with the ignition off, listening to the radio, when "Economy Mode Active" appeared on the display. I switched the radio off, and started the engine , it ran as before, with just the Electronic Ignition message for the usual 15 secs. I will not go back to the main dealer, they left the car in a real mess. I've not much faith in the auto-electrician either, he didn't seem to have much idea at all. I've changed the air and fuel filters, what should I try next before putting a match to the car?

hdi 90, 110 or 136?

HDI 90, James.

Have you checked that the turbo is boosting as it should ? The intake pipe that runs from the turbo to the engine can be blown off or split (not the one from airbox to turbo - and its a pig to re-secure because you can't easily get at it) or maybe a blocked air intake ?

I'd start looking there is there has been such a sudden large decrease in power.

I'll have a look in the morning if the weather's OK, and let you know what I find. I don't think the turbo is working, but that wouldn't account for the sudden reduction in speed which happens quite regularly. Can a faulty turbo or damaged pipe do that?

It would effect the cars performance if turbo was faulty but i would not say that is your problem. Have you checked air filter?have you put an injection cleaner in? i always use shell diesel in my car as it has cleaners in the fuel. Also i think people call them maf's now i know them as air flow meters It could be thats playing up and sticking. with the amount of miles i would point to maf or air flow meter. Its like driving a car that is under fueling hence lack of power. and the symptoms you are describing. Hope that helps.

Yes, I suspected the air flow meter (isn't there a fuel pressure sensor too?) or similar. I've just changed the air and fuel filters so can rule that out. Doubt whether it would be injectors, it runs pretty smoothly at all times, just loses power. As far as I know an air flow meter is too expensive to buy one just to try. My local; garage owner has said that if they get another HDI in, he'll swap a couple of items temporarily to try to establish the fault. Unfortunately none of his regular customers has turned up with one yet.

air flow meter and rail pressure sensors will log faults if there faulty

If either of these items is faulty, will the fault logged identify the item in question, or will it be of a more general nature? I only ask because of my previous experiences with having fault codes read!

the air flow meter if faulty may flag up crank angle sensor, cam angle sensor, egr valve or the air flow meter itself and the rail pressure sensor will usually flag up the a rail pressure sensor fault, i.e. signal to high or low, it wont say signal missing as if the signal was missing it wouldnt fire

OK, I'll have to get it checked, just hate paying out for a diagnosis every time there's a fault! Is there any reasonably priced equipment to allow me to read faults myself? BTW, pity your "shed" isn't an estate!

bgsats wrote:OK, I'll have to get it checked, just hate paying out for a diagnosis every time there's a fault! Is there any reasonably priced equipment to allow me to read faults myself? BTW, pity your "shed" isn't an estate!

unfortunatley there is no suitable fault code readers for the 406 hdi, well unless you want to spend £1,000+ for a bosch or snap on scanner , if your lucky enough to have a 2004 onwards 406 hdi, then you can get a cheap obd2 code reader but anything earlier than this wont work

If your turbo is knackered, or you are not getting enough air into the engine it will be dead obvious. Plant the foot and if these is no black smoke the engine is not starved of air, if there is a cloud of black smoke for a prolonged period of time then you are definately looking at an air/fuel ratio problem (i.e turbo or air mass sensor)

Hope this helps.
DW
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Car is a 1999, I won't be spending £1000 on a scanner! No black smoke!

jameslxdt wrote: unfortunatley there is no suitable fault code readers for the 406 hdi, well unless you want to spend £1,000+ for a bosch or snap on scanner , if your lucky enough to have a 2004 onwards 406 hdi, then you can get a cheap obd2 code reader but anything earlier than this wont work

My brother bought a cheap job of ebay for around £60, i ve plugged it into my 1999 hdi and it read the codes fine, (had one minor about starting system)