Malibu L4-2.4L (2010)
Fuel: Testing and Inspection
Fuel Composition Diagnosis
Fuel Composition Diagnosis
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
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Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
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Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure Instructions)
provides an overview of each diagnostic category.
Circuit/System Description
When an E85 compatible vehicle is built, an engine control module (ECM) or powertrain control module (PCM) replaced, or when the learned alcohol
content has been reset with a scan tool, the fuel system will need to contain ASTM gasoline with 15 percent or less ethanol content. If the fuel in the fuel
system needs to be drained and replaced with ASTM gasoline, the engine will need to run at operating temperature and consume at least 1 liter (0.3
gallon) of fuel before the system will recognize the correct alcohol content. Either ASTM gasoline or ASTM E85 fuel can then be used. In order that the
ECM/PCM recognizes a proper next fuel fill, the amount must be 11 liters (3 gallons) or more, and the ethanol content must be between 0-85 percent.
Reference Information
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Special Tools
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J 44175 - Fuel Composition Tester
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J 44175-A - Fuel Composition Tester
Circuit/System Verification
1. Observe the Fuel Composition Learn parameter using the scan tool. The Fuel Composition Learn parameter should display Inactive.
Note:
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The key needs to be turned OFF for at least 30 seconds after the parameter displays Inactive to properly store the ethanol learned
value in the ECM/PCM memory.
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The vehicle may need to be driven more than 11 km (7 mi) with the engine at operating temperature.
‹› If the Fuel Composition Learn parameter displays Active, drive the vehicle until the Fuel Composition Learn parameter displays Inactive.
2. Record the ECM/PCM estimated value of the ethanol content using a scan tool.
3. Record the actual measured percentage of ethanol content using the J 44175 - Tester or J 44175-A - Tester. The ECM/PCM estimated value
should be within 15 percent of the ethanol content measured with the J 44175 - Tester.
‹› If the ECM/PCM estimated value is not within 15 percent of the ethanol content measured with the J44175 Tester continue with
Circuit/System Testing.
Circuit/System Testing - J44175 Ethanol Content Less Than 15 Percent
1. Use the scan tool to reset the Fuel Alcohol Content parameter to 3 percent.
2. Use the scan tool to reset the fuel trim values.
Circuit/System Testing - J44175 Ethanol Content More Than 15 Percent
1. Perform a complete key cycle, key ON, engine OFF, in order to ensure that the ECM/PCM recognizes a refueling event.
Note: It may be necessary to partially drain the fuel tank.
2. Key OFF, add at least 11 liters (3 gallons) of non-blended gasoline to the fuel tank.
3. Use the scan tool to reset the Fuel Alcohol Content parameter to 3 percent.
Note: In order to ensure the non-blended gasoline has reached the fuel injectors, the vehicle may need to be driven more than 11 km (7 mi) with