PO 171 fuel system to lean to bank 1 97 Honda Accord 165k miles
Engine light came on for 2 days, then turned off on it's own. Friend noticed no oil in tank, took almost a gallon of oil. Last oil change at Honda dealership was 1,000 miles ago. Took car to a garage where they pulled the PO 171 error. Could this be something as simple as they didn't put some cap on tight enough after last service?
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Re: PO 171 fuel system to lean to bank 1 97 Honda Accord...
Yes. I would clean the engine with engine cleaner and then watch for any oul leaks. For you to use that much oil there would be a major leak. If no leaks check to see if blue smohe is coming out you tailpipe. If not keep an eye on is I this it will be fine if none of these things are wrong. I hope this helps. Don't forget to rate my answer. thanks.
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PO 171 Bank 1 too lean PO 174 Bank 2 too lean Why ? The front O2 Sensors need to be replaced at 100,000 miles or sooner, if they have actually failed They are reading too lean because the system is too rich & the computer is driving the fuel trim or injector pulse lean, thus the codes or failed sensors, yes both Have to check fuel trim with a scan tool Have to check fuel pressure Have to check there are no leaking injectors Have to check for Vacuum Leaks from the intake all the way to the exhaust converter Your working a rich condition keeping in mind the system is driven lean You look at fuel trim short & long,sort of a past history of events May want to look at converter temps also The converters won't last long if you have or has a rich condition from fuel or cylinder misfires Now the spark plugs can't be over 3 years old & no mifires,get that out of the way before working the O2 issues
You did not list a vehicle, so here are the generic codes. Code 171 is system lean bank one and code 174 is system lean bank two. The computer is getting a signal from the O2 sensors saying the fuel system is too lean, and the computer can not make it rich. Possible causes are low fuel pressure, vac leaks, EGR valve problems, and so on.
PO 171--is an O2 Sensor Code for a Lean Condition
on Bank 1 (right side exhaust)
PO 174 -- is an O2 Sensor Codes for a Lean Condition
on Bank 2 (left side exhaust)
You gave us no vehicle
You gave us no drivability issues or
If the O2's have 100,000 miles on them,change the (2)
closest to the engine. They are most likely worn out
& the switching times are too slow to control injector
pulse width & thus set a MIL Lamp (OBD2 Fault ) on
You can learn a lot on the internet if you put OBD2 in your
Search Engine (Internet Explorer,etc)
PO 134 = 02 SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 1 SENSOR1)
PO 153 =02 SENSOR CIRCUIT SLOW RESPONSE (BANK 2 SENSOR 1)
PO 154 =02 SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 2 SENSOR 1)
PO 155= 02 SENSOR HEATER CIRCUIT MALFUNCTION (BANK 2 SENSOR 1)
PO 171= SYSTEM TOO LEAN (BANK 1)
PO 174= SYSTEM TOO LEAN (BANK 2)
I WOULD SAY YOU HAVE FAULTY OXYGEN SENSORS CAUSING THE ENGINE TO RUN TOO LEAN REPLACE THEM AND YOU SHOULD BE BACK IN BUISNESS
These codes mean that the oxygen sensor is reading too "Lean" on both the left and right cylinder banks and the engine control system can't compensate any further to solve the problem. You may have a dirty or failing Mass Airflow Sensor that is miscalcuating the amount of airflow the engine is taking in which in turn can cause both of these codes to set. If the sensor is reporting less air than the engine is actually taking in then the engine computer will add only the amount of fuel it should based on what it was told by the sensor which will cause both cylinder banks to run "lean". There could be something else going on such as having two bad oxygen sensors [very rare] but I do see these two codes together quite often and usually its the sensor that is causing it. Hope this helps a bit!
P0421 - Warm Up Catalyst Efficiency Below Threshold (Bank 1)
P0171 - Fuel System Too Lean - (Bank 1)
P0446 - Canister Close Valve Malfunction
P1191/P1193 - Limp Home Valve - Low RPM Before replacing the catalytic converter (bank 1 next to the firewall, Bank 2 is near the radiator), you'll want to verify it is bad (most likely is it sinse you also have a 'lean' code for Bank 1 - probably clogged). This can also cause misfires and engine stumble (low RPM) that's probably where the 1191/1193 occurred. The final DTC, P0446 - Canister Close Valve Malfunction, could be the valve itself, or the wiring between it and the PCM. Check the connector & pins for any damage/corrosion. Hope this helps
DTC P0171 and Po174 indicate air/fuel ratio is correcting rich for an overly lean condition. You could have several things causing this 1. fuel system malfuntion 2. EGR system malfunction 3. Air intake vacuum leak 4. Engine oil level to high 5. Incorrect cam timing 6. Restricted air cleaner 7. Faulty PCV system 8. Excessive internal engine wear.
Sorry I could not be more specific. Check for the easy things in this list. Most of the time one of the o2 sensors in bank one has failed and not reading correctly. Same on the 02 Lesabre.