Good afternoon,
This code usually indicates that the system is running lean.
https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers
If you have a scan tool, can you tell me the long-term trim percentage? This will tell me if you have a vacuum leak.
Roy
Engine Control
P2191 System too Lean at Higher Load (Multiple) (Bank 1) - General Information
General Description
In order to provide the best possible combination of drivability, fuel economy and emission control, the PCM uses a closed loop air/fuel metering system. The PCM monitors the HO2S signal voltage and adjusts fuel delivery based it in closed loop fuel control. Changes in fuel delivery will be indicated by the long-term and the short-term fuel trim values. The ideal fuel trim value is around 0%. The PCM will add fuel when the HO2S signal is indicating a lean condition. Additional fuel is indicated by fuel trim values that are above 0%. The PCM will reduce fuel when the HO2S signal is indicating a rich condition. Reduction in fuel is indicated by fuel trim values that are below 0%. The DTC relevant to fuel trim will be set when the amount reaches excessive levels because of a lean or rich condition.
DTC Description
If the lambda controller reaches the maximum or minimum threshold, then feedback control is no longer possible and emissions will be increased. The PCM sets DTC P2191 if no proportional post catalyst fuel trim adaptation occurs for a defined time after the lambda controller has reached its maximum threshold at part load.
Engine Control
P2191 System too Lean at Higher Load (Multiple) (Bank 1) - Inspection/Repair:_:W/Harness Inspection
Check intake/exhaust system for leakage
1. Visually/physically inspect the air leakage in intake/exhaust system for the following areas:
- Vacuum hoses for splits, kinks and improper connections.
- Throttle body gasket.
- Gasket between intake manifold and cylinder head.
- Seals between intake manifold and fuel injectors.
- Exhaust system between HO2S and Three way catalyst for air leakage.
2. Was a problem found in any of the above areas?
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3. Inspect the leakage in EVAP. system for the following conditions:
(1)Remove the manifold side vacuum hose from the EVAP canister purge valve.
(2)Using a hand vacuum pump apply specified vacuum(Approx. 15 in, Hg) to the manifold side of the valve.
(3)Does the valve hold vacuum?
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Sensor Inspection
NOTE:
Refer to "Signal Waveform & Data" in the "General Information" procedure.
1. Visually/physically inspect the front HO2S for the following conditions:
- Ensure that the HO2S is securely installed.
- Silicon contamination. This contamination will be indicated by a white powdery coating on the portion of the sensor exposed to the exhaust stream and this will result in a but false(high) voltage signal.
- Fuel, engine coolant or oil contamination.
- Use of improper sealant.
- If contamination is evident on the HO2S, Fix the source of the sensor contamination before replacing the sensor to prevent future contamination. Go to "Verification of Vehicle Repair" procedure.
2. Visually/physically inspect the MAFS for the following conditions:
- Contamination or deterioration.
- Poor connection or damaged harness.
3. Check for an intermittent TPS1 false signal. TPS1 signal displayed on a GDS should increase steadily when depressing accelerator pedal after starting.
4. Verify that the PCM ground connections are clean and properly tightened.
5. If test result is NG, repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
If OK, go to next step as below.
NOTE:
If the contamination is evident on the HO2S or MAFS. Fix the source of the sensor contamination before replacing the sensor to prevent future contamination.
Positive Crankcase Ventilation System Inspection
1. Check the engine oil level. The oil level should be between the min. and max. marking. Fill to the correct oil level.
2. Check crankcase ventilation valve for improper installation, damaged o-rings and malfunctioning.
3. Warm up the engine to normal operating temperature.
4. Connect GDS and note the "SHORT TERM FUEL-B1" parameter on the GDS data list.
5. Disconnect and plug the positive crankcase ventilation at the intake manifold side.
6. Monitor the "SHORT TERM FUEL-B1" parameter on the GDS data list once again.
Specification :The value should remain more or less unchanged
7. Is the displayed value within the specified value?
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Fuel System Inspection
1. Fuel Line Pressure Inspection
(1)Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
(2)Install a fuel pressure gage.
(3)Inspect fuel pressure with normal idle status.
Specification :338 - 348kPa(3.45 - 3.55kg/cm2)
(4)Is fuel pressure within the specified value?
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2. Fuel Pressure Hold Inspection
(1)Stop the engine and check for a change in the fuel pressure gauge reading.
Specification :After engine stops, the gauge reading should hold for minimum 5 minutes
(2)Is fuel pressure within the specified value?
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Monday, March 22nd, 2021 AT 10:55 AM
