Hi everyone!

We tend to post and share the most challenging, complicated cases in the forums, and we escape over the cases that we manage to fix easily. As a result, reading a forum, we mostly see the horror stories, but not the easy fixes. So this time, I am going to share with you guys about how easy it was for me to fix my engine light as a reminder to always start from the basics.

A few months ago the engine light of my 2006 LR3 SE V8 with 148K miles came on. Codes were P0171 and P0174, which mean too much air, or too little fuel in both banks. Having an advance code reader can be a huge help to narrow down the problem. But well, many of us don't have that type of equipment. So I started from the basics, and go up step by step.

My first step was to clean the MAF sensor. A faulty MAF sensor which reports wrong amount of air can cause these two codes. I used a MAF sensor cleaner and thoroughly sprayed and cleaned the sensor. I did not record a video on how to do this, but you can see this procedure in this nice youtube video:


I cleared the code, and nope, the engine light came on with the same codes. Next I focused on air intake system to see is there any crack in it. If there is a crack after the MAF sensor, the engine can suck extra unmeasured air through it, which can trigger these two codes. I spotted a hairline crack on the air intake tube right after the MAF sensor. As a temporary fix and to test is this the source of the problem or not, I taped the crack (I will be replacing the cracked tube with a new OEM part). I cleared the codes, and after driving for a few miles the codes returned back.

So I started to think that if the problem is not too much air, maybe it is too little fuel. A weak fuel pump, clogged fuel filter or clogged injectors could create a situation in which the engine receives too little fuel. Before digging deep into the fuel system, somehow I remembered a pack of injector cleaners that I had purchased awhile ago and never managed to use them. I said what the hell, let's give it a try! I poured one in the tank, cleared the codes, took the truck to the highway in the middle of the night when there is no traffic, drove the truck hard and did multiple wide open throttles in the second gear (basically an Italian tune), and guess what, the codes never came back, and it has been more than two weeks! Today I took the truck for its annual emission and safety test, and it passed with flying colors!

Multiple points:
1- An engine light is not necessarily a dead sentence or an expensive bill. Sometimes it can be very easy to fix. Always do the basics before throwing expensive parts at the problem hoping they will fix the problem.

2- Doing basic annual check and cleaning goes a long way towards maintaining a healthy car. I tend to stay on top of car maintenance, but admittedly I failed to follow my own advice on this LR3. This is my back-up truck for heavy hauling, dirty works, or bad weather, and most of the time it sleeps in the garage and forgotten.

3- Cleaning MAF sensor, visually inspecting under the hood for cracks, broken parts, or any other problem, and using some form of injector cleaner should be a part of annual checklist and maintenance.

4- I usually use top tier, premium 93 octane gas. Although top tier gas comes with ingredients to clean the engine, some say it is still recommended to use dedicated injection cleaner products. I do not have any scientific evidence to support these claims, but in my case these cleaners helped me to solve the problem. This post is not sponsored by any product, and I am not even including the name of the brand that I used.

5- Last but not least, I am amazed how reliable these LR3s are! This 14 years old, high mileage truck has been rock solid, and it still looks sharp with special thanks to its timeless design!

 

Thanks for this. Very very much.
But FYI, you do have the wrong codes in the title (1701 and 1704 instead of 0171 and 0174), fortunately I did a search including post texts and the text is correct.

Thanks again.