HELP--OBDII System Too Lean Bank 1,2

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Author Message   Crash (Crash) Posted on Tuesday, May 28, 2002 - 11:49 am:    I have a 2000 Disco II My Service Engine Soon light is on and the OBDII codes are 171, 174 which are the System Too Lean Bank 1 and Bank 2 respectively. I am looking for advice on what the problem might be. I was informed (Nathan at Discount Rovers who is always a big help) that the O2 sensors are usually codes 44, 45 so I can only guess (MAF Sensor?) at what the problem could be. The car runs fine, the idle is slightly off--it flucuates between 600 and 800 sometimes when warm, and gas mileage seems about right. All help is appreciated. Best regards, Chris   Carl Muckenhirn (Carlmuck) Posted on Tuesday, May 28, 2002 - 01:25 pm:    171, and 174 are the proper OBDII codes for O2 Sensor problems (one of many). More interesting would be to actually pull the trim levels and see if they make sense. 44 and 45 are OBDI codes (pre-GEMS). carl.   Crash (Crash) Posted on Tuesday, May 28, 2002 - 03:59 pm:    What do you mean by pull the trim levels? I would be happy to pull them, but I don't know what to pull-- Also, I might be slightly off on the numbers that Nathan gave (they were in the 40's) for the O2 sensors, and the OBD2 codes that I show for the 40's are all for HO2S HEATER CONTROL CIRCUITs. Isn't this the O2 sensors? This is the first time I have had to deal with codes, so I am still trying to comprehend all this stuff. All help is appreciated! (needed!)   Carl Muckenhirn (Carlmuck) Posted on Tuesday, May 28, 2002 - 04:17 pm:    Depending upon what OBD2 reader you have, you may be able to read the actual input parameters on most of the sensors in the Rover. Of interest for the codes you called out would be the Short and Long Term Fuel Trim for both banks 1 and 2 (A and B). The short-term values should bounce around (+/- 10% when warmed up), but average out to real close to 0%. The long term is usually around 10%. As for the OBD codes, Rover doesn't use any below P0101 (at least I don't see any in the manual). There are two catalytic converter related ones at P0420 and P0430,(kind of like 40's) but I don't think you'd see them if you only had bad o2 sensors. The Rover codes related to the heater control circuits are between P1185 and P1196. carl.   Crash (Crash) Posted on Tuesday, May 28, 2002 - 09:21 pm:    Thanks for the info. I was looking at some generic codes off a OBDII site--and it turns out they are not correct. According to the RAVE CD, the correct codes for 171 and 174 are System too Rich, under the Engine Management System for Fuel Injectors. Which still leaves me "guessing" on what the problem is. So, two more questions--what should I check next and what is the best OBDII tester that gives more than just codes for the best price possible. Thanks   Leslie N. Bright (Leslie) Posted on Wednesday, May 29, 2002 - 09:22 am:    http://www.obd-2.com/ http://www.spanishtrailrovers.com/Tech/Info/OBDII_Scan_Codes/obdii_scan_codes.html -L   Crash (Crash) Posted on Wednesday, May 29, 2002 - 09:46 am:    O.K. I just ordered the OBD-II test kit from OBD-II so I can check what is going on. However, does anyone know if the OBDII codes for system too lean is correct or if the Rave CD saying System too Rich is correct?   Carl Muckenhirn (Carlmuck) Posted on Wednesday, May 29, 2002 - 12:10 pm:    From the manual: P0171 - Oxygen Sensor System Too Lean Fault Bank A P0172 - Oxygen Sensor System Too Rich Fault Bank A P0174 - Oxygen Sensor System Too Lean Fault Bank B P0175 - Oxygen Sensor System Too Rich Fault Bank B