I cant find out what is causing these lean codes on bank 1 &2.
I have a 2001 silverado 4.8 and it is giving me a lean code on bank 1 & bank 2. I replaced the intake gaskets and the fuel pressure regulator. I've replaced all four oxygen sensors and i have a K&N filter on it. I've cleaned the map sensor, maf, and the throttle body, nothing. What could cause this?
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Sounds like you have a serious vacum leak.; DTC 0174 and 0174 are lean conditions on bank 1 and bank 2, 0300 is random misfire. The only thing I can think of is a big vacum leak like the brake booster / vac line leaking, or maybe the intake manifold is cracked ... even a stuck-open EGR doesn't normally lean a motor that much. Start by checking for a vacum leak, if the motor will idle you can spray a little WD-40 around ports and lines >> if the idle speeds up or becomes smooth you on the right track in the area you judt sprayed.
code p0128 indicates a mechanical fault ( could be the thermostat stuck open)
code p0174 -system too lean -bank2 ===causes --intake /exhaust leak--fuel pressure/pump--injectors--AIR system--hose connection/s
code po171 refers to system too lean bank 1 same as po174 with the HO2S sensor being the culprit. As to all being related . only by way of the o2 sensors
code p0442 is not connected to the first 3 as it is in a different section of the fuel system
Check for loos connections between the intake and the tube from the air filter. Check if the clamp is loose or leaks in the tube which can cause an incorrect reading. Other than that it may be a dirty MAF sensor which can be fixed by spraying carb cleaning or tuner spray in the intake or it may be bad or a bad oxygen sensor;.
oxygen sensor failure P0171 System too Lean (Bank 1) - Read Our Article On Oxygen Sensor Codes For Help With This Generic Check Engine Light Code P0174 System too Lean (Bank 2) - Read Our Article On Oxygen Sensor Codes For Help With This Generic Check Engine Light Code
hope this is a bit of a push in the right direction ...
Basically this means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is generally the side of the engine that doesn't have cylinder #1. A code P0174 may mean that one or more of the following has happened: •The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. •There could be a vacuum leak downstream of the MAF sensor. Possible solutions include: •In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for its location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling •Inspect all vacuum and PCV hoses, replace if necessary •Check for a dirty fuel filter and proper fuel pressure
ALL CARS fixes are guessing and hoping at best. 1st thing is it a 4 cylinder or a v6. if its a v6 and you have bank 1 lean but NOT bank 2 lean, then you are probably looking for a vacuum leak affecting only bank 1. Stuck injector will NOT ause this code without also setting a misfire code. Cars use fuel trim. Basically you have BASE FUEL which is the preprogrammed best fuel amount for each condition. FUEL TRIM is the result of when the o2 sensor analyzes how rich or lean the car was, then adjusts the fuel trim to compensate as needed. Most cars set a trouble code around +/-25% fuel trim. You really need look at datastream on a scantool and determine if BANK 2 is also lean and just not quite at code level (IE - Bank 1 is at 25% and set a code, Bank 2 is at 22% and did not). In this case, tream it as a problem that affects ALL CYLINDERS instead of a bank. Now that the bank thing is settled, lets presume you have a 4 cylinder. As said before, vacuum leaks are a common cause and should be checked early on. There are many ways to do this, but the cheapest and easiest is open the hood and listen for the air whistling/sucking sound and follow it. Doesnt always work, but you may get lucky.