I am still fighting these codes. There have been some changes.

A: I found a vacuum leak, and fixed it. Now the truck idles great, and generally runs awesome. However, instead of the codes showing up every third day or so, they not pop up every time I drive it.

B: further Web searching has resulted in utter confusion. It would appear thay there are several "official land rover specific code lists" and they all differ In their definitions, some don't even include a 1175 code on the list.....so what do these codes actually mean?


I just want to know where else I can look for the problem rather than just throwing parts at it.

 

You don't have access to another Bosch MAF sensor? Maybe 1 that can be borrowed from a friend? Do you know of a local junk yard or recycler where you can find a cheap take-off to try out? Do you still have your original MAF sensor stashed somewhere? Take it out and clean the sensor with MAF/electrical contact cleaner. Aftermarket sensors usually produce more problems than are actually solved. There are a lot of threads in regard to this: Cheap MAF, Oxygen, etc type sensors rarely hold up and don't communicate well with the Bosch ECU in these trucks. I would hate to throw pricey parts at this, also, given that you don't fully understand the fault codes but understand in the future that you will save yourself a lot of hassle by using only the genuine replacement parts that came on the vehicle. You should be searching for another genuine sensor to at least try out in place of the cheap 1 to find if any changes occur; from there you can buy the genuine part if that is warranted, or continue searching for the issue elsewhere. Be sure that you don't have any more vacuum leaks remaining, although it seems you have that in order. Refer to the RAVE workshop guide and search for your fault codes. I will search for it as well and see if I can come up with anything as I have it right here in front of me.

Per workshop manual the 1172 is "system too rich bank-1" 1175 is for bank-2
LR description: additive injector adaptive fueling, lean limit exceeded on that bank.
This is p. 18-2-35 under Engine Mgmt System

It falls under fuel injectors but being on both banks the issue has to be further upstream with 1 of the sensors, like the Mass Air Flow, perhaps.

 

Have the D2 manual in pdf format? If so search manual using pdf search function for code. Only takes a few seconds and you get the official "official" description.
......

 

My Manuel has this to say

 

Mine too. chubb's hunt-n-pecker on the keyboard fail?
......

 

According to some reading, "additive injector adaptive fueling" is done at idle. Multiplication is done at all engine speeds.

This makes sense as the codes only pup up at idle.

What I don't understand is whether Fuel trim and injector adaptive fueling are the same thing or correlated. For instance, a negative fuel trim means that the computer is pulling fuel to adjust for a rich condition. So by these definitions, does "rich limit exceeded" mean that the computer has told the injectors to shorten their pulse widths as much as it possibly can bit the o2's are still reporting a rich condition? Or that the computer has cranked the injectors on to the max, and as a result has over compensated and caused the rich condition?


​​​​​is short term fuel trim the same thing as additive injector adaptation? Two names for the same data?


P.s. yes I double posted. Damn smart phone moves seamlessly from thread to thread and makes it easy to post in the wrong place

 

Just wanted to follow up on this for the sake of posterity.

After installing a known good Bosch MAF and walker O2 sensors, I've been code free (fingers crossed) for some time now.

I believe the bosch O2's were the problem. My fuel trims were consistently positive 1.0-4.0% ish and now they are completely opposite, same range but on the negative side. So a component was reporting incorrectly and causing the computer to compensate in the wrong direction.

I believe it was the O2's specifically because one started acting sluggish and lead into an O2 wiring fiasco, but at least one O2 was definitely bad and had probably been reporting innacurately for some time, but not far enough out of spec to throw an unresponsive code until recently.

The cheap rebuilt MAF could have been playing a part in the issue as well but I was code free prior to doing head gaskets and am not convinced that sensors just go bad of their own Accord (even remanufactured ones) without some kind of stimulus, I.e water intrusion, voltage spike, blunt force trauma, etc.

 

Use
http://enginecodemaster.com

Any little bit of antifreeze on an O2 ruins it.

Engine Code: P1172

Land Rover Engine Code: P1172 = Rich Fueling Fault

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