How to solve Land Rover LR3 “The Clean Codes”—P0171&P0174

Problem description:

I own a 2006 Land Rover LR3 with 30,000 miles on it. Several days ago, its engine light came on. I took it to the dealer and they rebooted my computer and it seemed fine for about a week, but the engine light came back again. I then replaced my battery. It was way over do. When I hooked up the new battery the engine light went off for about 10 miles and came right back on. I applied JLR Mangoose diagnostic cable to it and got the 2 codes:

OBD II P0171 Fuel System Too Lean

OBD II P0174 Fuel System Too Lean

When I brought it to the dealer, they claimed throttle body needed cleaning. I paid them 500 bucks to "clean it" and the light came back on my way home from the dealer. I have been reading on forums and believed it is the MAF, but then the JLR Mangoose cable gave me a new code p0170.

I was totally confused. So I called my brother, an amateur mechanic, for help and finally fixed it by following his advices:

He said that typically when you got the two codes together it is one of two issues - either a vacuum leak or a dirty or failing Mass Air Flow sensor. He suggested me try cleaning the MAF. If there are no other codes related to the MAF, I would lean towards it being a vacuum issue.

I tried what he told me and bought a Mass Air Flow Sensor Cleaner from a local shop, and I am pleased to tell you guys that it worked, although it took a little longer than I thought it would.

I wrote this article hope to help those who met the same problems, just for sharing my experience of using this diagnostic cable and software, you should try it at your own risk!