I have a 99 Disco II w/ 127k.Service engine soon light came on a couple of days ago. Went and had the codes read and came up with three; P0154, P0174, & P1174. The first one said O2 sensor ckt,no activity, bank 2, sensor one. The second code said O2 sensor, system to lean. The third code said something about the fuel air metering device. My question is what do I need to do to resolve this issue? Will the last two codes go away if I replace the o2 sensor, or will the first two go away if I replace the fuel air metering device? Thanks in advance for all your help.

William

 

At your mileage. you will need to replace all 4 O2 sensors. I believe if you do that then go have the codes cleared then all the lights should stay off.
Here is a good on line sit where you can get O2 sensore in the mid $65 range for both front and rears. http://www.roverconnection.com/
Mike

 

Thanks Mike. What is going on with that Fuel Air Metering device?

 

Was your O2 sensor bad or just unplugged? It is quite likely your MAF code is being thrown because of the O2 sensor error. Fix the first problem, clear the codes and see if it comes back.

 

I agree, replace the 02 sensors then see if you still have the last fault after you have them cleared.
Mike

 

The first code is the O2 sensor, then the fuel to lean code, and the lst code is the fuel metering device in that order.

 

OH my mistake. I misread the reply. I thought there was confusion about the order of the errors. Disregard my last reply. Thanks. The thing that puzzles me though is my Service Engine Soon light went out over the weekend. Does the ECU reset itself periodically? Just wondering if I need to still fix the problem. Can dirt in the fuel tank casue one of these errors to come up when fuel get low?

Thanks,
Wm

 

There is no specific code for dirt in the fuel, there are codes that can be caused from dirt, such as an injector being plugged up or a lean code cause your engine can't get enough gas do to a plugged up fuel filter.
As for the ECU, if the check engine light went off it is most likely because it was not a hard code that the ECU had but a soft code that when rechecked looked OK and the ECU cleared it.
Mike

 

A short in your O2 sensor connection (loose, cut wire, etc) may have thrown a soft code. It may stay out, but it will probably come back unless you can chase down the problem.

 

Right. The CES lightis back on now. I am going to have it read again to see if it comes up with the same codes. I guess I should check to see if the o2 sensors are properly connected. I should probably just go ahead and replace all four sensors, huh?

Thanks,
Wm