Jaquar X series 2002 auto/ secondary warning light above message centre comes when car hit 60 mph plus {2/0000} RPS ...codes PO171 P0174 done all the usuals sensors /vcuum test etc etc...anyone have other possibilities?

 

What "vacuum tests" have you done?

 

Harry, the codes you have are for vacuum leaks. Since you have both P171 and P0174, that is telling me that it is up near the throttlebody most likely or it is a fairly severe vacuum leak. With that being said, start with the "big 3". These would be the PCV hose (tends to split on the backside of the hose, normally found on the PCV hoses that are smooth, the ribbed ones do not seem to split), IMT O-rings, and the brake booster hose (run from top of the intake to the brake booster on the firewall, the little "football" in the middle of the line will either crack or start to become crumbly and fall apart in your hand when you rub it). After checking these 3 things, then you are most likely looking at either upper and/or lower intake o-rings. if you are getting this far, just bite the bullet and do both. It is an extra half hour, but it will ensure you don't have to waste 3 hours going back in for the lowers only.

Lets see what you have after this and then we can take things further.

 

shall update you .thank you~

 

Also, check fuel trims (as so often posted) to make sure it is indeed a leak or at least an ordinary one.

Eventually if you find it's not then check the freeze frame data for extra clues.

 

Hi Thermo

Read codes again
P0171 P0174 .and now P1000?

 

P1000 is a "good code". If you have this, what that is saying is that there are no codes currently active in the car and it is attempting to complete all of the driving cycles to get you back to "P1111".

I would say to clear the codes and take the car out for a drive. After a 20 mile drive, read the codes and see what you have. If you have done some repairs, this will tell you whether or not they were successful.

 

Er.... P1000 is not really good. It's quite bad.

It means the OBD monitors have not set (aka completed) OK.

P1111 would mean they have - as you would want.

Either P1000 or P1111 will always be present. Other codes may also be. P1000 does NOT imply no other codes (nor does P1111).

---

A fair number of regions check the OBD monitors and only allow specific ones (or none) to be unset or else fail the car for inspection (aka smog test). People tend to think P1111 / P1000 is what they check for but actually those codes are non-generic so instead they just check the actual OBD monitor statuses, which are generic.

 

thanks thermo!..off now!

 

Every code clear will cause P1000 because the clear also clears the OBD monitors (as required by law in your & my country).

The car then needs to relearn things and most (but not all) codes cannot occur before it has.

If all is OK, in due course the monitors will set and as a result the P1000 will change to P1111.

If all is not quite OK, one or more monitors will fail to set. Many codes will be suppressed in that situation.

Anyone with a smog test due soon should not clear the codes without being aware they may not get enough monitors to set in time for the test and also may not get codes to assist in diagnosis... (a sort of Catch-22)