CarObdCode.Com

0

P0171 Fuel Trim System Lean Bank 1

Author: carobdcode/Categories: OBDii Powertrain Codes/Time: 2013-08-08 06:06
59

P0171 Fuel Trim System Lean Bank 1

Possible causes
- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection
Tech description
If the P0171 is combined with the P0174 code, it’s very likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replaced the air filter and clean the air flow meter. If the problem persist the front oxygen (O2) sensor may need to be replaced.

2006 Trailblazer P0171

User Submitted Video

What about the obd code?
- Fuel injection system does not operate properly.
- The amount of mixture ratio compensation is too small. (The mixture ratio is too lean.)
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
P0171 Description

The Engine Control Module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the ECM adds HO2S inputs to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicates a rich condition, the FT values will be below 0 percent. The short term FT values change rapidly in response to the HO2S voltage signals. The long term FT makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

Note:

1. Need to look up additional OBD-II Trouble Codes(DTC), use the search box. Enter the 5 character trouble codes in the search box and submit the search. You can repeat the search as many times as you need, one diagnostic code per search.
2. Don't assume a particular OBDii code means the same for other automotive manufacturers as there are many manufacturer specific codes in use.
3. If your trouble codes are for a different automotive, select that vehicle series before searching for the diagnostic codes because not all OBD2 codes used by one manufacture are used by the other manufactures. The search only looks at OBD codes valid for the currently selected manufacturer.
4. This code is for reference only.
5. Help us improve CarObdCode.com. Tell us fix the code. Any information is appreciated. Thanks.

Leave a Reply