This started with what i thought to be vibration from my auto box, i have had my auto box serviced and it has made a huge difference but the vibration i was getting when driving has not gone away.

This vibration i get is mostly when the car has been driven 20 miles, if driving up a hill it gets worse. Recently i have been driving a bit further than my usual 23 miles to work and the EML came on, the car seems to run worse the further i go. In neutral and idling the engine is shaking thru the steering wheel. The engine sounds a bit noisy at low revs too when this happens. So the vibration in neutral indicates its not gearbox related. My car has 77k miles.

So i used my ebay diagnostic lead and scanmaster software and i got these DTC's - P02AA P121A P02A7

any searching i have done has not come up with much, so can anyone elaborate on these codes or is this software limited to finding out what is wrong with the injectors?

I have been considering the terraclean treatment, its anyones guess if it will cure this problem. However i would rather put the £90 towards getting the injectors refurbed than getting the terraclean done.

The car has lowish miles, it seemed the previous owner has it sitting around a lot not getting used. So the terraclean may help f maybe they injectors need a refurb.

HELP please.

 

I'd be tempted to go with the results of Search (on P121A) on here. The replies look helpful. Search on the UK forum, too as again replies look OK.

Every P1 code is make-specific and can be model- and/or year- and/or engine- specific, too. So it's fair the OBD software didn't know it.

I don't know many of the diesel-specific codes.

edit: hmm, that P121A may be a Ford code. Don't know if Jag & Ford had synchronised their codes. The 2.7D is the only S-Type to use a Siemens PCM so most of the data I have probably does not apply.

Leedsman is probably on the right track. I'd go for Forte rather than Terraclen but not convinced either will help.

I believe the injectors DO need coding if you swap one, unlike the ones for all the petrol S-Types.

 

Oh yeah i forgot to mention its a diesel. I have posted on the uk forum too to try and widen my chances of help.

If i do need to get the injectors fixed, the less the better, i would probably just pay for them to be refurbished. Usually second hand injectors cost a bomb anyway.

I read the post by leedsman, but terraclean was not around here back then in the uk.

Would the terraclean not stand a better chance of cleaning the injectors than forte. I did used diesel purge on a bmw 320d and boy was it feekin messy.

 

I wouldn't use it but it's your car and money. I don't think anything but remove & clean will work if it's the injectors. There's huge pressure. If that can't remove any hypothetical deposits I don't think a cleaner will.

 

cheers, i first need to establish if the problems are caused by clogged/ blocked injectors.

i dont know if the injector removal is a diy job or not.

 

Might be but beware of the VERY high pressures which are a serious safety issue. Can cut through flesh, I understand.

 

I have heard this too although when i have disconnected fuel lines from injectors and fuel rails in the past there is just a slight release as the nut is loosened.

 

You can easily drain the fuel pressure to zero. I am lazy so I start the car then trip the inertia switch and let it run until it stalls.
No more fuel pressure.

You can also use the Schrader valve on the passenger side of the engine to release the pressure. It does spew gas on the engine so do it when things are cold like over night.
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Engine off - fuel pressure remains high but pump is off so not much can come out if you undo a connector.
Engine on - be afraid.

Diesel pressures are MUCH higher than petrol.