| Author | Message | ||
     James Anderson (Jnjander) New Member Username: Jnjander Post Number: 5 Registered: 08-2003 |
Got the Service Engine light on a 99 Discovery II, took it to Autozone and the code was P0174, "System too lean" Any ideas? The guy from Autozone said it was probably an oxygen sensor. Does this sound correct? And if it is the oxygen sensor, from what I read there are 4 of them...do they all have to be replaced. Forgive me if these are stupid questions, only 8 days as a Land Rover owner. | ||
| Bill Collett (Bcollett) New Member Username: Bcollett Post Number: 7 Registered: 07-2003 |
If it is the O2 sensor then you just have to replace one or both on that side. PO174 is say the system is to lean on bank 2. I'm not sure what side bank 2 is on the discoveries. I have also heard that it can be your Mass Air Flow sensor. You can try cleaning that off with some electrical contact cleaner. | ||
| James Anderson (Jnjander) New Member Username: Jnjander Post Number: 6 Registered: 08-2003 |
Thanks for the advice. Where would I find the mass air flow sensor, is that near the air filter? | ||
| Jorge D. Hinojos (Tenoch) Member Username: Tenoch Post Number: 46 Registered: 02-2003 |
James, I had the same problem for some time now (Disco II, 99). when I took it to the autozone I got the same code "Bank 1 and 2 too lean". then I thought it was the sensors, but recently, I took it to the nearest dealership (300 miles) and they told me that it was the mass air flow sensor. Nathan from discount rovers told me that a mass flow sensor can be expensive, but he is checking on prices as I write. this is the first time that I hear you can clean it so I would like to learn more I buy one. has any one done it? again, it could be the oxygen sensors, but it makes sense to start with the most inexpensive alternative and work down the list. my 2 cents | ||
| James Anderson (Jnjander) New Member Username: Jnjander Post Number: 8 Registered: 08-2003 |
At least I am not alone in this battle. If anyone knows about celaning the mass air flow sensor,please help. | ||
| Bill Collett (Bcollett) New Member Username: Bcollett Post Number: 11 Registered: 07-2003 |
What I have heard is that you just spray the grid section, which is a like a filter. Any oil and dirt can cause it to malfunction. If you clean it with contact cleaner and it still does not work, you will probably have to replace it. According to my service department, LR has a lot of trouble with thier MAFs. | ||
| Bill Collett (Bcollett) New Member Username: Bcollett Post Number: 12 Registered: 07-2003 |
What I have heard is that you just spray the grid section, which is a like a filter. Any oil and dirt can cause it to malfunction. If you clean it with contact cleaner and it still does not work, you will probably have to replace it. According to my service department, LR has a lot of trouble with thier MAFs. | ||
| Jorge D. Hinojos (Tenoch) Member Username: Tenoch Post Number: 47 Registered: 02-2003 |
where is the mass air flow sensor located? | ||
| marc olivares (Pugs) Member Username: Pugs Post Number: 119 Registered: 12-2002 |
james and jorge yes, your MAF can be cleaned. the MAF is located upstream of the airbox. disconnect the plug, and retaining straps, and use a good quality electrical contact cleaner. spray the interior wire mesh grid and the side venting ports in the interior of the MAF. there are two wire leads that are centered in the throat of the MAF just behind the mesh. these wires send the differential temp. readings that calculate the amount of air that the engine is receiving. make sure that these leads are clean. i have used Pura Lectron 2020 contact cleaner on quite a few MAFs with good results. often times you'll hear that K&N air filter oil will cause these sensors to prematurally fail due to over-oiling, but a good cleaning will most often correct this problem. best of luck to you, marc oh, make sure that the MAF is completely dry before reinstalling. | ||
| marc olivares (Pugs) Member Username: Pugs Post Number: 120 Registered: 12-2002 |
with that said, don't assume that this is a MAF issue. PO174 is a lean bank code on your long term fuel trim. other issues could be your problem and your (bank 2) o2 sensors may be correctly reading the increase in oxygen in your air/fuel mixture to that side. look at other things that might lean (i.e. add air) to that bank: an air leak (vacuum) sticking fuel injector (not opening) stuck egr valve miss fire in ignition on that bank "look for anything that could increase o2" look at the basics before you start throwing money at it. what would be best is to check the values from both banks to determine if it truly is exclusive to bank 2 (ie bank 2 threw the code before bank 1 did). now if you're not completely confused, have at it and start with the basics good luck, marc | ||
| James Anderson (Jnjander) New Member Username: Jnjander Post Number: 9 Registered: 08-2003 |
I cleaned the MAF yesterday with the electrical contact cleaner, reset the light and have driven about 70 miles since...no light. As I was cleaning it, I noticed a well cooked bug on the mesh screen, maybe that was part of the problem. We shall see. Thanks for all of the help. |
