Re:Nhờ các Bác giúp lỗi P 2096 (Fuel trim too lean)
To bác i30.
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P2096
http://www.alldatapro.com.../142425543/139995095')]Notes[/link]
DTC P2096 POST CATALYST FUEL TRIM SYSTEM TOO LEAN (BANK 1)
GENERAL DESCRIPTION
In order to provide the best possible combination of drivability, fuel economy and emission control, the
ECM uses a closed loop air/fuel metering system. The ECM 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 ECM 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 ECM 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
ECM sets DTC P2096 if no proportional post catalyst fuel trim adaptation occurs for a defined time after the lambda controller has reached its maximum threshold.
DTC Detecting Condition
MONITOR SCANTOOL DATA
NOTE: If any codes relating to Rear HO2S or TWC (Three Way Catalyst Converter) are stored, do ALL REPAIRS associated with those codes before proceeding with this troubleshooting tree.
[*]Check DTC Status [/OL] [*]Connect scantool to Data Link Connector (DLC).[*]IG "ON".[*]Select "Diagnostic Trouble Codes (DTCs)" mode, and then Press F4 (DTAL) to check DTC's information from the DTCs menu[*]Read "DTC Status" parameter. [/OL]
[*]Is parameter displayed "History (Not Present) fault"?
NOTE: [/OL] [UL] [*]History (Not Present) fault: DTC occurred but has been cleared.[*]Present fault: DTC is occurring at present time. [/UL] [/UL]
YES - Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor conception, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Component Inspection" procedure.
COMPONENT INSPECTION
[*]Check Exhaust system [/OL] [*]Visually/physically inspect the following conditions: [/OL] [UL] [*]Exhaust system between HO2S and Three way catalyst for air leakage, restriction and damage.[*]Damage, and for loose or missing hardware [/UL] [/UL] [*]Was a problem found in any of the above areas?
YES - Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to next step as below. [/OL] [*]Check TWC [/OL] [*]Visually/physically inspect the three-way catalyst (TWC) converter for the following damage: [/OL] [UL] [*]Severe discoloration caused by excessive temperature[*]Dents and holes[*]Internal rattle caused by a damaged catalyst [/UL] [/UL] [*]Also, ensure that the TWC is a proper original equipment manufacturer part.[*]Was a problem found?
YES - Replace TWC and go to "Verification of Vehicle Repair" procedure.
NO - Go to next step as below. [/OL] [*]Check HO2S [/OL] [*]Visually/physically inspect the HO2S for the following conditions: [/OL] [UL] [*]Ensure that the HO2S is securely installed. (Pigtail and wiring harness not making contact with the exhaust pipe)[*]Check for corrosion on terminals and terminal tension (at the HO2S and at the
ECM)[*]Front HO2S for 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. [/UL] [/UL] [*]Warm up the engine to normal operating temperature and let it idle.[*]Connect Scantool and monitor the "
O2 SNSR VOL-B1/S1" and "O2 SNSR VOL.-B1/S2" parameters on the Scantool data list. Specification : [/OL] [UL] [*]Front HO2S (
O2 SNSR VOL.-B1/S1) : Approx.
0 - 1 V with idle after warm up Sensor voltage increase during engine acceleration and decrease during engine deceleration [/UL] [/UL] Approx.
0 V - 0.4 V when fuel cut
[*]Rear HO2S (
O2 SNSR VOL.-B1/S2) : Above
0.4 V at idle [/UL] [*]Was a problem found in any of the above areas?
YES - Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Check for poor connection between
ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure. [/OL]
VERIFICATION OF VEHICLE REPAIR
[*]Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode[*]Press F4 (DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions[*]Read "DTC Status" parameter[*]Is parameter displayed "History (Not Present) fault"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure. [/OL]
