I just got a P 1173 code, "Down stream fuel trim malfunction (bank 2) - Front sensor aged - rear HO2S adaption too lean/too rich (RH Bank) (NAS and EU-3 only).

What sensor? O2? It knows that it is old?

Doing a search in the service manual I only get the above hit (in the P code table), no other reference.

Rod

 

Have you done any work on the truck recently?


An O2 sensor might be your problem, but from my experience 1171(LH) and 1173(RH) are lean codes caused by a vacuum leak. Air is entering your system somewhere after the MAF sensor and you a running lean. I would check PVC and brake servo vacuum lines where they connect to the upper intake. If you can't find a leak then you might consider doing a smoke test to try and find the leak.

Here is a post I made for doing a smoke test with a cigar. This is how I found my vac. leak and solved my 1171 and 1173.
https://landroverforums.com/forum/di...s-cigar-54235/

 

Read up on this first:-
Tech Tips - Eastern Manufacturing
T/V

 

Thanks for the reply. Have I done any work on the truck recently? Umm, yes, I had the engine replaced about 500 miles ago. It is quite possible that there is a bad vacuum connection. Anyway, that seems to be the logical place to start.

BTW, I have a Lucas smoke generator to replace the smoke that leaks out of the Lucas electrical system on my 55 MG and 67 Jaguar. Can I use that in place of the cigar? My wife keeps hiding my cigars.

Rod

 

You can make the smoke any way you want. The cigar is just the cheapest way i've found. You can use the same instructions for the cigar method and pump smoke into the same location using your Lucas smoke machine.