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Engine Controls and Fuel - 2.4l - Troubleshooting and Diagnosis Chevrolet Malibu VII

Testing & Diagnostics ~15024 words

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.

Symptoms Description

Symptoms covers conditions that are not covered by DTCs. Certain conditions can cause multiple symptoms. These conditions are listed together under Symptoms Testing. Conditions that may only cause specific symptoms are listed separately under Additional Symptoms Testing. Perform the Symptoms Testing before using the Additional Symptoms Testing.

Symptoms Verification

Before using the Symptom tables, perform the following inspections

  1. Ensure that the malfunction indicator lamp (MIL) is operating correctly. Use the scan tool to command the lamp ON and OFF.
  2. Ensure that there are no DTCs that are stored.
  3. Ensure that the scan tool data is within a normal operating range. Refer to «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for scan tool information.
  4. Verify the customer concern.
  5. Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.

Identifying Intermittent Conditions

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movements of a component. Refer to the following for a list of issues that may cause an intermittent condition

  1. Moisture and water intrusion in connectors, terminals, and components
  2. Incomplete connector mating
  3. Poor terminal contact
  4. High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
  5. Harness that is too short or tight
  6. Wire insulation that is chaffed or cut
  7. High or low ambient temperature
  8. High or low engine coolant temperatures
  9. High underhood temperatures
  10. Heat build up in component or circuit due to circuit resistance, poor terminal contact, or high electrical load
  11. High or low system voltage
  12. High vehicle load conditions
  13. Rough road surfaces
  14. Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
  15. Incorrect installation of aftermarket, add on accessories

Visual/Physical Check

  1. Ensure that the control module grounds are clean, tight, and correctly located.
  2. Ensure that the vacuum hoses are not split or kinked, and are properly connected, as shown on the Vehicle Emission Control Information label.
  3. Ensure that the air filter is clean and free from restrictions.
  4. Ensure that there is no water intrusion in connectors terminals and components.
  5. Inspect the air intake ducts for the following conditions: Collapsed Damaged areas Looseness Incorrect installation Leaking
  6. Inspect for air leaks at the throttle body mounting area, the mass air flow (MAF) sensor and intake manifold sealing surfaces.
  7. Inspect the wiring harness for the following conditions: Poor connections Pinches Cuts
  8. Inspect for loose, damaged, unseated, or missing sensors/components.
  9. Inspect the terminals for corrosion and correct contact.

Symptoms Testing

Backfire, Cuts Out/Misses, Detonation/Spark Knock, Dieseling/Run-On, Hard Start, Hesitation/Sag/Stumble, Lack of Power/Sluggishness/Sponginess, Poor Fuel Economy, Rough, Unstable, or Incorrect Idle and Stalling, or Surges/Chuggles

  1. Test the fuel system for the following: The fuel system for correct operation volume and pressure-Refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) . The fuel injectors for proper operation-Refer to «Fuel Injector Diagnosis (With J39021 or With Tech 2)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) or «Fuel Injector Diagnosis (With CH47976)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) . The fuel quality condition-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) . For vehicles which are E85 compatible, you may also refer to «Fuel Composition Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  2. Test the ignition system for the following: Spark plugs for incorrect heat range or an abnormal condition-Refer to «Spark Plug Inspection»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__spark-plug-inspection) and «Ignition System Specifications»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__ignition-system-specifications) . For diagnosis of coolant or oil fouled spark plugs-Refer to «Coolant in Combustion Chamber»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures__coolant-in-combustion-chamber) or «Oil Consumption Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures__oil-consumption-diagnosis) . Wet down the secondary ignition system with water from a spray bottle-Wetting down the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as the water is applied. Weak spark using the J 26792 Spark Tester-Refer to «Electronic Ignition System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  3. Inspect for the following conditions: The proper operation of the transmission torque converter clutch (TCC) - The scan tool should indicate an engine speed drop when the TCC is commanded ON. For Non-Hybrid equipped vehicles, refer to «Torque Converter Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/automatic-trans/#automatic-transaxle-6t306t406t45-symptom-troubleshooting-and-diagnosis) . The proper operation of the A/C compressor An engine that runs lean or rich-Observe the Fuel Trim parameters with a scan tool. Refer to «DTC P0171 or P0172»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-dtc-p0010-to-dtc-p0366) . Inspect the heated oxygen sensors (HO2S). The HO2S should respond quickly to different throttle positions. CAUTION: Refer to «Heated Oxygen and Oxygen Sensor Caution»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#dangers-warnings-and-cautions__heated-oxygen-and-oxygen-sensor-caution) . Water intrusion in the HO2S connector NOTE: The embossed arrows on the mass air flow (MAF) sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Inspect the MAF sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Install the MAF in the proper direction. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . Inspect the mass air flow (MAF) sensor connections. Engine oil contaminated by fuel Vacuum hoses for splits or kinks-Verify that the routing and connections are as shown on the Vehicle Emission Control Information label. Knock sensor system for excessive spark retard activity-Observe the Knock Retard parameter on the scan tool for activity more than 0°.
  4. The exhaust system components for the following: Physical damage or possible internal failure The three-way catalytic converters for a restriction For more information, refer to «Symptoms - Engine Exhaust»(/chevrolet/malibu/vii-2008-2012/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  5. Electromagnetic interference (EMI) on the reference circuit can cause a misfire condition. You can usually detect EMI with a scan tool by monitoring the engine speed parameter. A sudden increase in the engine speed parameter with little change in actual engine speed indicates that EMI is present. Inspect the high voltage components near the ignition control circuit if a condition exists.
  6. The crankcase ventilation valve for proper operation-Refer to «Crankcase Ventilation System Inspection/Diagnosis (Without Turbocharger)»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures) .
  7. Evaporative emission (EVAP) canister purge solenoid that is stuck open
  8. The engine cooling system for the following conditions: The thermostat is the correct heat range. Refer to «Thermostat Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) . Proper engine coolant level-If the level is low, refer to «Loss of Coolant»(/chevrolet/malibu/vii-2008-2012/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
  9. The crankshaft position sensor for an intermittent condition-Observe the scan tool CKP Resync Counter parameter. The Resync Counter parameter should remain at 0 during all operating conditions, and when moving the related harnesses and connectors between the crankshaft position sensor and the ECM.
  10. Inspect the engine for the following mechanical failures: Refer to «Symptoms - Engine Mechanical»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures) . Excessive oil in the combustion chamber or leaking valve seals Oil Consumption Incorrect cylinder compression Sticking or leaking valves Worn camshaft lobes Incorrect valve timing Worn rocker arms Broken valve springs Excessive carbon buildup in the combustion chambers-Clean the chambers with top engine cleaner. Follow the instructions on the can. Incorrect engine parts
  11. If the above conditions do not address the symptom, refer to the additional symptoms tests.

Additional Symptoms Tests

Hard Start With RPO LE5 or LE9

  1. Observe the TB Idle Airflow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Cleaning»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__throttle-body-cleaning) .
  2. Test the engine coolant temperature (ECT) sensor. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__temperature-versus-resistance) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  3. Test the fuel pump relay operation. The fuel pump should turn ON for 2 s when the ignition is turned ON. Refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  4. Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-repair-instructions-off-vehicle-1-of-2) .

Hard Start With RPO LAT

  1. Inspect the throttle body for an excessive accumulation of deposits in the throttle bore and clean, if necessary. Refer to «Throttle Body Cleaning»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__throttle-body-cleaning) .
  2. Test the engine coolant temperature (ECT) sensor. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__temperature-versus-resistance) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . If the sensor is within the specifications, test the ECT sensor circuits for high resistance.
  3. Test the fuel pump relay operation. The fuel pump should turn ON for 2 s when the ignition is turned ON. Refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  4. Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-repair-instructions-off-vehicle-1-of-2) .

Hesitation, Sag, Stumble

  1. Test the fuel pressure. Refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  2. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  3. Test the generator. Refer to «Symptoms - Engine Electrical»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) . Repair the charging system if the generator output voltage is less than 9 V or more than 16 V.
  4. Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-repair-instructions-off-vehicle-1-of-2) .
  5. Test the manifold absolute pressure (MAP) sensor. Refer to «DTC P0106»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-dtc-p0010-to-dtc-p0366) .
  6. Engine warm and idling, verify the correct operation of the camshaft actuator system. Command the intake and exhaust camshaft actuators from 0 degrees to 25 degrees and back to zero while observing the scan tool Int. CMP Variance and Exh. CMP Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters is greater than 2 degrees, inspect the suspect camshaft actuator and camshaft actuator solenoid valve and valve bore for contamination, obstruction, and damage. Refer to «Camshaft Position Actuator Solenoid Valve Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) and «Camshaft Actuator System Description»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-description-and-operation) .

Poor Fuel Economy with RPO LE5 or LE9

  1. Heavy loads being carried or towed
  2. Acceleration rate too much or too often
  3. Inspect the brake system for brake drag.
  4. Inspect for incorrect operation of the speedometer.
  5. Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (2.4L)»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__engine-control-module-scan-tool-information) list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__temperature-versus-resistance) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  6. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  7. Observe the TB Idle Airflow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Cleaning»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__throttle-body-cleaning) .

Poor Fuel Economy with RPO LAT

  1. Heavy loads being carried or towed
  2. Acceleration rate too much or too often
  3. Inspect the brake system for brake drag.
  4. Inspect for incorrect operation of the speedometer.
  5. Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (2.4L)»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__engine-control-module-scan-tool-information) list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__temperature-versus-resistance) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  6. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  7. Inspect the throttle body for an excessive accumulation of deposits in the throttle bore and clean, if necessary. Refer to «Throttle Body Cleaning»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__throttle-body-cleaning) .

Detonaton/Spark Knock

  1. Inspect for excessive carbon buildup in the combustion chambers. Clean the chambers with Top Engine Cleaner. Follow the instructions on the can.
  2. Test for an engine overheating condition. Refer to «Engine Overheating»(/chevrolet/malibu/vii-2008-2012/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .
  3. Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (2.4L)»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information__engine-control-module-scan-tool-information) list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__temperature-versus-resistance) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  4. If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicle minimum octane requirements.

Lack of Power, Hesitation, or Cut Out

  1. Inspect the engine electrical system for correct operation. Refer to «Symptoms - Engine Electrical»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) .
  2. Verify that each injector harness is connected to the correct injector.
  3. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  4. Engine warm and idling, verify the correct operation of the camshaft actuator system. Command the intake and exhaust camshaft actuators from 0 degrees to 25 degrees and back to zero while observing the scan tool Int. CMP Variance and Exh. CMP Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters is greater than 2 degrees, inspect the suspect camshaft actuator and camshaft actuator solenoid valve and valve bore for contamination, obstruction, and damage. Refer to «Camshaft Position Actuator Solenoid Valve Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) and «Camshaft Actuator System Description»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-description-and-operation) .

Rough, Unstable, or Incorrect Idle and Stalling With RPO LE5 or LE9

  1. Observe the TB Idle Airflow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and clean, if necessary. Refer to «Throttle Body Cleaning»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__throttle-body-cleaning) .
  2. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  3. Inspect the engine mounts. Refer to «Engine Mount Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-repair-instructions-on-vehicle__engine-mount-inspection) .
  4. Inspect the intake and exhaust manifolds for casting flash.

Rough, Unstable, or Incorrect Idle and Stalling With RPO LAT

  1. Inspect the throttle body for an excessive accumulation of deposits in the throttle bore and clean, if necessary. Refer to «Throttle Body Cleaning»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__throttle-body-cleaning) .
  2. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  3. Inspect the engine mounts. Refer to «Engine Mount Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-repair-instructions-on-vehicle__engine-mount-inspection) .
  4. Inspect the intake and exhaust manifolds for casting flash.

Surges/Chuggles

  1. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  2. Test the heated oxygen sensors (HO2S). The HO2S should respond quickly to a change in throttle position. If the HO2S do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The PCM reduces the amount of fuel delivered to the engine, causing a driveability condition.
  3. Verify that each injector harness is connected to the correct injector.

Fuel Odor

  1. Saturated EVAP canister-Refer to «Evaporative Emission Control System Description»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-description-and-operation) .
  2. A condition with the internal components of the fuel tank assembly-Refer to «Fuel System Description»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-description-and-operation) .
  3. Inspect for damaged or deteriorated fuel lines.

ECM Commanded Reduced Engine Power With RPO LE5 or LE9

Review the Reduced Engine Power Indication History parameter with a scan tool to determine the reason for the last reduced engine power event.

ECM Commanded Reduced Engine Power With RPO LAT

Perform the Diagnostic System Check - Vehicle to determine the reason that the ECM has commanded the reduced engine power mode.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

Ignition voltage is supplied to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control circuit. For example, a failure condition exists if the ECM detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON.

Reference Information

Schematic Reference

  1. «Instrument Cluster Schematics»(/chevrolet/malibu/vii-2008-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
  2. «Engine Controls Schematics (LAT)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-wiring-schematics) or «Engine Controls Schematics (LE5)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-wiring-schematics)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
  2. Command the MIL ON and OFF with a scan tool while observing the following control circuit status parameters: MIL Ckt. Short Gnd Test Status MIL Ckt. Open Test Status MIL Ckt. Short Volts Test Status Each parameter should change from OK and Not Run or from Not Run and OK.
  3. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

  1. Ignition ON, verify that the instrument panel cluster (IPC) warning indicators are illuminated. If the IPC warning indicators are not illuminated, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, replace the IPC.
  2. Ignition OFF, disconnect ECM X1 harness connector. Ignition ON, the MIL should not illuminate. If the MIL is illuminated, test the MIL control circuit terminal listed below for a short to ground. If the circuit tests normal, replace the IPC. ECM terminal X1-27 for RPO LE5 ECM terminal X1-12 for RPO LAT
  3. Ignition ON, connect a 3A fused jumper wire between the MIL control circuit terminal listed below and ground. The MIL should illuminate. ECM terminal X1-27 for RPO LE5 ECM terminal X1-12 for RPO LAT If the MIL does not illuminate, test the MIL control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC/bulb.
  4. If all circuits/connections test normal, replace the ECM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Instrument Cluster Replacement»(/chevrolet/malibu/vii-2008-2012/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for replacement. setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Description

The purpose of the evaporative emission (EVAP) Service Bay Test is to aid in resetting the EVAP inspection/maintenance system status. For this vehicle that is equipped with the engine off natural vacuum diagnostic, the Service Bay Test uses the scan tool to initiate the engine control module (ECM) regular sequence of EVAP system DTC tests, but with different enable criteria. By using the Service Bay Test the inspection/maintenance indicator can be set without the need for multiple cold soaks.

The scan tool displays for the Service Bay Test are based on the events that occur within the following three categories

  1. The engine running portion of the tests-The vehicle must remain at rest, in Park, or in Neutral, during this portion of the test. This test inspects for large leaks, a leaking purge valve and/or vent system restrictions. The scan tool will display test progress or the reason for an abort or failure.
  2. Drive cycle-The scan tool will display time and distance needed to warm the fuel.
  3. Ignition OFF-During this portion of the test, the engine controller will remain active for up to 45 minutes when the ignition is turned OFF to allow control of the EVAP canister vent valve and run the engine off natural vacuum test. The engine controller inspects for small leaks during this period by monitoring fuel tank pressure or vacuum. If the system is sealed, there will be a pressure or vacuum change. Pressure or vacuum changes that are less than the calibrated values indicate a leak.

When the EVAP diagnostics are initiated by the Service Bay Test, the scan tool will indicate if the enable conditions listed below are not met, or will display a specific reason if the test aborts. When complete, the display will indicate that the tests passed or failed.

Conditions for Running the Test

The following conditions must be met in order to enable the Service Bay Test

  1. The battery voltage is between 11-18V.
  2. The engine coolant temperature (ECT) is less than 35°C (95°F) at start-up.
  3. The EVAP inspection/maintenance system status indicator is set to NO.
  4. The fuel level is 15-85 percent capacity and cannot be refueled during the tests.
  5. There are no DTCs displayed.
  6. The vehicle must be driven for the time and distance specified on the scan tool.
  7. The ambient air temperature is between 0-40°C (32-104°F).
  8. The ignition must remain OFF during the engine OFF portion of the test, and the vehicle must remain at rest.

Test Procedure

Note. If the Service Bay Test aborts or fails, a DTC will NOT be set.

  1. Install a scan tool.
  2. Select the Service Bay Test with the scan tool.
  3. Follow the instructions on the scan tool. If the test aborts, correct the condition for running the test, then retest. If the test fails, repair the vehicle for the condition indicated by the failure message on the scan tool.
  4. Verify that the EVAP inspection/maintenance system status is set to YES.
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This Engine Cranks but Does Not Run diagnostic is an organized approach to identify a condition which causes the engine to crank but not start. This diagnostic directs the technician to the appropriate system diagnosis.

Diagnostic Aids

Inspect for any of the following conditions

  1. Insufficient fuel can cause a no start condition. Thoroughly inspect the fuel delivery system for sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.
  2. Fuel injectors with partially blocked and restricted nozzles, or a malfunctioning solenoid, can cause a no start condition. Refer to «Fuel Injector Diagnosis (With J39021 or With Tech 2)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) or «Fuel Injector Diagnosis (With CH47976)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  3. There may be fuel spray at the fuel injectors and the indicated fuel pressure may be correct, yet there may not be enough fuel to start the engine. If the fuel injectors and the injector circuit are OK, and fuel spray is detected, the fuel injector ON time may be inadequate. If the engine control module (ECM) receives incorrect inputs from the various information sensors, the fuel delivered by the fuel injectors may be inadequate to start the engine. Check all the engine data parameters with a scan tool and compare the values indicated with the expected values or the values from a known good vehicle.
  4. Check the crankshaft position (CKP) sensor engine reference signal with a scan tool. Observe the Engine Speed parameter while cranking the engine. The scan tool should indicate a steady 200-300 RPM while cranking. If erratic values, such as sudden spikes in the engine speed are displayed, the engine reference signal is not stable enough for the engine to start and run properly.
  5. Inspect the engine for good secure electrical grounds.
  6. If the engine almost starts and then stalls, check for an open in the ground circuits of the CKP sensor and the camshaft position (CMP) sensor.
  7. Water or foreign material in the fuel can cause a no start or engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 minutes in a heated repair shop. The malfunction may not recur until parked overnight in freezing temperatures. Extreme weather conditions can cause contaminated fuel to prevent the vehicle from starting.
  8. A vehicle that starts and runs after being brought to the repair shop for a no start condition, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and the wiring in order to check for an engine starting or will not stay running concern.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. CH 48027: Digital Pressure Gauge
  2. CH 48027-100: Digital Pressure Gauge
  3. J 26792 (SA91992): HEI Spark Tester
  4. J 43244: Relay Puller Pliers

Note. This diagnostic assumes the following: The battery is completely charged. Refer to Battery Inspection/Test . The engine cranking speed is acceptable. Refer to Engine Cranks Slowly . There is adequate fuel in the fuel tank.

  1. Crank the engine for 15 seconds. Observe the DTC information with a scan tool. The following DTCs should not be set: DTC P0201-P0204, P0230, P0335, P0336, P0351, P0353, P0601, P0602, P0603, P0604, P0606, P0607, P060E, P062F, P0685, P0690, P1516, P1682, P2610. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ignition ON, observe the Theft Deterrent parameter with a scan tool. The parameter should display Disabled. If Enabled is displayed, refer to «Symptoms - Engine Controls»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  3. Ignition OFF, disconnect the fuel pump relay using the J 43244: Pliers.
  4. Connect a J 26792 (SA91992): Tester to the boot of an ignition coil of a cylinder and ground.
  5. While cranking the engine, verify that the spark tester sparks. If there is no spark, refer to «Electronic Ignition System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  6. Ignition OFF, install the fuel pump relay.
  7. Ignition ON, command the fuel pump ON with a scan tool. You should hear the fuel pump turn ON. If the fuel pump does not turn ON, refer to «Fuel Pump Electrical Circuit Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  8. Ignition OFF, install the CH 48027: Pressure Gauge or CH 48027-100: Digital Pressure Gauge. Refer to «Fuel Pressure Gauge Installation and Removal (LE5)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  9. Ignition ON, command the fuel pump ON with a scan tool. The fuel pressure should be between 345-414 kPa (50-60 psi). If the fuel pressure is not within the specified range, refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  10. Verify that the following conditions do not exist: Collapsed air intake duct to the throttle body Restricted air filter element Spark plugs for being gas or coolant fouled A skewed manifold absolute pressure (MAP) sensor-Refer to «DTC P0106»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-dtc-p0010-to-dtc-p0366) . A skewed engine coolant temperature (ECT) sensor-Refer to «Temperature Versus Resistance»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__temperature-versus-resistance) . Exhaust system restricted-Refer to «Restricted Exhaust»(/chevrolet/malibu/vii-2008-2012/remont/exhaust/#engine-exhaust-system) . Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) . Engine mechanical condition, for example, worn timing belt or low compression-Refer to «Symptoms - Engine Mechanical»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures) or «Engine Compression Test»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-24l-diagnostic-information-and-procedures__engine-compression-test) . If you find any of the above conditions, repair as necessary.
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Battery Voltage-Relay Switch Side12
Fuel Pump Supply Voltage123
Fuel Pump Relay ControlP0230P0230P0230
Fuel Pump Relay GroundP0230P0230
Fuel Pump Ground2
1 Open fuel pump fuse, cranks no start 2 Cranks no start 3 Fuel pump operates continuously, discharges battery

The engine control module (ECM) enables the fuel pump relay when the ignition switch is turned ON. The ECM will disable the fuel pump relay within 2 seconds unless the ECM detects ignition reference pulses. The ECM continues to enable the fuel pump relay as long as ignition reference pulses are detected. The ECM disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.

The following conditions may cause the fuel pump fuse to open

  1. The fuse is faulty.
  2. There is an intermittent short to ground in the supply voltage circuit of the fuel pump.
  3. The fuel pump has an intermittent internal condition.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 43244: Relay Puller Pliers

Note. An open or a short to voltage in the control circuit will cause both the Ckt Open Test Status and the Ckt Short Volts Test Status parameters to display Fault.

Ignition ON, command the fuel pump relay ON and OFF with a scan tool while observing the following control circuit status parameters

  1. Fuel Pump Relay Ckt Short Gnd Test Status
  2. Fuel Pump Relay Ckt Open Test Status
  3. Fuel Pump Relay Ckt Short Volts Test Status

Each parameter should toggle between OK and Not Run or Not Run and OK.

  1. Ignition OFF, disconnect the fuel pump relay using the J 43244: Pliers.
  2. Ignition ON, verify that a test lamp illuminates between the ground circuit terminal 85 and B+. If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance.
  3. Verify that a test lamp does not illuminate between the ground circuit terminal 85 and the control circuit terminal 86. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Remove the test lamp.
  5. Command the fuel pump relay ON with a scan tool. Verify the scan tool Fuel Pump Relay Ckt Short Gnd Test Status parameter is OK. If not the specified value, test the fuel pump relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  6. Install a 3 A fused jumper wire between the fuel pump relay control circuit terminal 86 and the ground circuit terminal 85. Command the fuel pump relay ON with a scan tool. Verify the scan tool Fuel Pump Relay Ckt Short Gnd Test Status parameter is Fault. If not the specified value, test the fuel pump relay control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  7. Inspect the fuel pump fuse. If the fuel pump fuse is open, test for the following conditions: A short to ground in the relay switch B+ circuit A short to ground in the supply voltage circuit of the fuel pump If the above circuits test normal, replace the fuel pump module.
  8. Verify that a test light illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  9. Connect a 15 A fused jumper wire between the B+ circuit terminal 30 and the supply voltage circuit terminal 87 of the fuel pump. Verify the fuel pump is activated. If the fuel pump does not activate, test for the following conditions: An open/high resistance in the supply voltage circuit of the fuel pump An open/high resistance in the ground circuit of the fuel pump If the above circuits test normal, replace the fuel pump module.
  10. If all circuits test normal, test or replace the fuel pump relay.

Component Testing

  1. Ignition OFF, disconnect the fuel pump relay.
  2. Test for 70-110 ohms between terminals 85 and 86. If the resistance is not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the relay.
  4. Install a 15 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Tank Fuel Pump Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions)
  2. «Relay Replacement (Attached to Wire Harness)»(/chevrolet/malibu/vii-2008-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/chevrolet/malibu/vii-2008-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) enables the fuel pump relay when the ignition switch is turned ON. The ECM will disable the fuel pump relay within 2 seconds unless the ECM detects ignition reference pulses. The ECM continues to enable the fuel pump relay as long as ignition reference pulses are detected. The ECM disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.

The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the fuel pump module, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.

The fuel tank stores the fuel supply. An electric turbine style fuel pump attaches to the fuel pump module inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel pump module. The function of the venturi pump is to fill the fuel pump module reservoir. The fuel pressure regulator, a part of the fuel pump module, maintains the correct fuel pressure to the fuel injection system. The fuel pump module contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. CH 48027: Digital Pressure Gauge
  2. J 37287: Fuel Line Shut-off Adapter
  3. J 37287-FF: Fuel Line Shut-off Adapters, if equipped with an LE9 engine

Note. Inspect the fuel system for damage or external leaks before proceeding. Verify that adequate fuel is in the fuel tank before proceeding. The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. Before proceeding with this test, review the User Manual CH 48027-5 for Safety Information Instructions.

  1. Ignition ON, engine OFF, command the fuel pump relay ON with a scan tool. You should hear the fuel pump turn ON and OFF. If the fuel pump does not operate, refer to «Fuel Pump Electrical Circuit Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  2. Ignition OFF, all accessories OFF, install a CH 48027: Pressure Gauge. Refer to «Fuel Pressure Gauge Installation and Removal (LE5)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  3. Ignition ON, engine OFF, command the fuel pump relay ON with a scan tool. Verify the fuel pressure is between 345-414 kPa (50-60 psi) and does not decrease more than 34 kPa (5 psi) in 1 minute.
  1. Ignition ON, engine OFF, command the fuel pump relay ON with a scan tool and observe the fuel pressure gauge while the fuel pump is operating. Verify the fuel pressure is between 345-414 kPa (50-60 psi). If the fuel pressure is greater than the specified range, replace the fuel pump module. If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the fuel pump module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
  2. Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 minute. If the fuel pressure decreases more than the specified value, perform the following procedure: Ignition OFF, relieve the fuel pressure. Refer to «Fuel Pressure Relief (without CH 48027-100)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__fuel-pressure-relief-without-ch-48027-100) or «Fuel Pressure Relief (with CH 48027-100)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . Install the J 37287: Shut-off Adapter or the J 37287-FF: Adapter between the fuel feed pipe and the fuel rail. Open the valve on the J 37287: Shut-off Adapter or the J 37287-FF: Adapter. Ignition ON, command the fuel pump relay ON with a scan tool and bleed the air from the CH 48027: Gauge. Command the fuel pump relay ON and then OFF with a scan tool. Close the valve on the J 37287: Shut-off Adapter or the J 37287-FF: Adapter. Monitor the fuel pressure for 1 minute. If the fuel pressure decreases more than 34 kPa (5 psi) within the specified time, locate and replace the leaking fuel injectors. If the fuel pressure does not decrease more than 34 kPa (5 psi) within the specified time, replace the fuel pump module.
  3. Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 minutes. If the fuel pressure decreases more than the specified value, replace the fuel pump module.
  4. Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027: Gauge. The fuel pressure should not drop off during acceleration, cruise, or hard cornering. If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the fuel pump module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
  5. If the fuel system tests normal, refer to «Symptoms - Engine Controls»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Line Replacement - Chassis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions)
  2. «Fuel Injector Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions)
  3. «Fuel Tank Fuel Pump Module Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The control module enables the appropriate fuel injector pulse for each cylinder. The ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. A fuel injector control circuit DTC may not set, but a misfire may be apparent. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

When performing the fuel injector balance test, the scan tool is first used to energize the fuel pump relay. The fuel injector tester or the scan tool is then used to pulse each injector for a precise amount of time, allowing a measured amount of the fuel to be injected. This causes a drop in the system fuel pressure that can be recorded and used to compare each injector.

  1. Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
  2. Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.
  3. Perform the fuel injector coil test within the conditions of the customer's concern. A fuel injector condition may only be apparent at a certain temperature, or under certain conditions.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. CH-48027 Digital Pressure Gauge. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-special-tools-and-equipment) .
  2. J 39021 Fuel Injector Coil and Balance Tester
  3. J 44602 Injector Test Adapter. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-special-tools-and-equipment) .

Fuel Injector Coil Test

Verify the resistance of each fuel injector with one of the following methods

  1. If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each fuel injector should be 11-14 ohms. If the injectors measure OK, perform the Fuel Injector Balance Test - Fuel Pressure Test. If not within the specified range, replace the fuel injector.
  2. If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3 ohms. If the difference is equal to or less than 3 ohms, refer to «Fuel Injector Balance Test - Fuel Pressure Test»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis__fuel-injector-balance-test-fuel) for further diagnosis of the fuel injectors. If the difference is more than 3 ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.

Fuel Injector Balance Test - Fuel Pressure Test

  1. Install a fuel pressure gauge. Refer to «Fuel Pressure Gauge Installation and Removal (LE5)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  2. Turn ON the ignition, with the engine OFF.
  3. Command the fuel pump relay ON with a scan tool.
  4. Observe the fuel pressure gauge with the fuel pump commanded ON. The fuel pressure should be 345-414 kPa (50-60 psi). If the fuel pressure is not 345-414 kPa (50-60 psi), refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  5. Monitor the fuel pressure gauge for one minute. The fuel pressure should not decrease more than 34 kPa (5 psi). If the fuel pressure decreases more than 34 kPa (5 psi), refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  6. Perform the Fuel Injector Balance Test with Special Tool or the Fuel Injector Balance Test with Tech 2.

Fuel Injector Balance Test with Special Tool

  1. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 amp position.
  2. Connect the J 39021 to a fuel injector with a J 44602 . See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-special-tools-and-equipment) .
  3. Command the fuel pump relay ON and then OFF three times with a scan tool. On the last command, as the fuel pressure begins to slowly degrade and stabilize, select a fuel pressure within 34 kPa (5 psi) of the maximum pump pressure. Record this fuel pressure. This is the starting pressure at which you will pulse each injector.
  4. Command the fuel pump relay ON one more time and energize the fuel injector by depressing the Push to Start Test button on the J 39021 at the previously selected pressure.
  5. After the injector stops pulsing, select Min from the Display Mode and record the Min pressure.
  6. Clear the Min/Max results.
  7. Select Normal from the Display Mode.
  8. Repeat steps 2 and 4 through 7 for each fuel injector.
  9. Perform the Pressure Drop Calculation.

Fuel Injector Balance Test with Tech 2

  1. Command the fuel pump relay ON and then OFF three times with a scan tool. On the last command, as the fuel pressure begins to slowly degrade and stabilize, select a fuel pressure within 34 kPa (5 psi) of the maximum pump pressure. Record this fuel pressure. This is the starting pressure at which you will pulse each injector.
  2. With a scan tool, select the Fuel Injector Balance Test function within the Special Functions menu.
  3. Select an injector to be tested.
  4. Press Enter to prime the fuel system.
  5. Energize the fuel injector by depressing the Pulse Injector button on the scan tool at the previously selected pressure.
  6. After the injector stops pulsing, select Min from the Display Mode on the CH-48027 and record the Min pressure. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-special-tools-and-equipment) .
  7. Clear the Min/Max results on the CH-48027 . See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-special-tools-and-equipment) .
  8. Select Normal from the Display Mode on the CH-48027 . See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-special-tools-and-equipment) .
  9. Press Enter on the scan tool to bring you back to the Select Injector screen.
  10. Repeat steps 3 through 9 for each fuel injector.
  11. Perform the Pressure Drop Calculation.

Pressure Drop Calculation

  1. Subtract the minimum pressure from the starting pressure for one fuel injector. The result is the pressure drop value.
  2. Obtain a pressure drop value for each fuel injector.
  3. Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
  4. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 psi). If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 psi), replace the fuel injector.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The control module enables the appropriate fuel injector pulse for each cylinder. The ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. A fuel injector control circuit DTC may not set, but a misfire may be apparent. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

The Active Fuel Injector Tester (AFIT), CH-47976 , is used to test the fuel pump, fuel system leak down, and the fuel injectors. See Special Tools . Following the User Guide, CH 47976-11, and the on screen prompts or selections, will indicate the steps required to perform each of the available tests. The tester will perform all of the tests automatically and display results of the test. The results can also be down loaded for storage and printing.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Special Tools

CH-47976 Active Fuel Injector Tester. See Special Tools .

Verify the resistance of each fuel injector with one of the following methods

  1. If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each fuel injector should be 11-14ohms. If the injectors measure OK, perform the AFIT Test Procedure. If not within the specified range, replace the fuel injector.
  2. If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3ohms. If the difference is equal to or less than 3ohms, refer to «AFIT Test Procedure»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis__afit-test-procedure) . If the difference is more than 3ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.

AFIT Test Procedure

  1. Turn OFF all accessories.
  2. Turn OFF the ignition.
  3. Install the AFIT. Refer to the AFIT User Guide.
  4. Turn ON the AFIT and select the vehicle.
  5. Turn ON the ignition and perform the Injector Test. If the AFIT aborts testing due to fuel pressure or fuel leak down, refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  6. View the test results. If any injector exceeds the recommended tolerance, replace the injectors.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition 1 Voltage - Fuse to Splice12
Ignition 1 Voltage - Splice to Injector1P0201, P0202, P0203, or P0204
Fuel Injector 1 ControlP0201, P0300P0201, P0300P0201
Fuel Injector 2 ControlP0202, P0300P0202, P0300P0202
Fuel Injector 3 ControlP0203, P0300P0203, P0300P0203
Fuel Injector 4 ControlP0204, P0300P0204, P0300P0204
1 Open fuse, cranks no start 2 Cranks no start

The control module enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 44603: Injector Test Lamp

Engine idling, observe the following control circuit status parameters for each fuel injector

  1. Injector Ckt Short Gnd Test Status
  2. Injector Ckt Open Test Status
  3. Injector Ckt Short Volts Test Status Each parameter should toggle between OK and Not Run or Not Run and OK.
  1. Ignition OFF, disconnect the harness connector at a fuel injector.
  2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the fuel injector.
  3. Ignition OFF, connect a J 44603: Injector Test Lamp between the control circuit terminal B and the ignition circuit terminal A of each fuel injector one at a time.
  4. Engine cranking, the test lamp should flash for each injector. If the test lamp is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, replace the engine control module (ECM). If the test lamp is always OFF, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, test or replace the fuel injector. Refer to «Fuel Injector Solenoid Coil Test»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Injector Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions)
  2. «Control Module References»(/chevrolet/malibu/vii-2008-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The control module enables the appropriate fuel injector pulse for each cylinder. The ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. A fuel injector control circuit DTC may not set, but a misfire may be apparent. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Verify the resistance of each fuel injector with one of the following methods

  1. If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each fuel injector should be 11-14 ohms. If the injectors measure OK, perform the Fuel Injector Balance Test. Refer to «Fuel Injector Balance Test»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) . If not within the specified range, replace the fuel injector.
  2. If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3 ohms. If the difference is equal to or less than 3 ohms, perform the Fuel Injector Balance Test. Refer to «Fuel Injector Balance Test»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) . If the difference is more than 3 ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

When performing the fuel injector balance test with the fuel injector tester or the scan tool, the scan tool is first used to energize the fuel pump relay. The fuel injector tester or the scan tool is then used to pulse each injector for a precise amount of time, allowing a measured amount of fuel to be injected. This causes a drop in the system fuel pressure that can be recorded and used to compare each injector.

The CH 47976: Active Fuel Injector Tester, is used to test the fuel pump, fuel system leak down, and the fuel injectors. Following the User Guide, CH 47976-11, and the on screen prompts or selections, will indicate the steps required to perform each of the available tests. The tester will perform all of the tests automatically and display results of the test. The results can also be down loaded for storage and printing.

  1. Monitoring the Current Misfire Counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
  2. Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. CH 47976: Active Fuel Injector Tester
  2. CH 48027: Digital Pressure Gauge
  3. J 39021: Fuel Injector Coil and Balance Tester
  4. J 44602: Injector Test Adapter

Note. DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). Irregular fuel pressure readings may result due to hot soak fuel boiling. Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic. Before proceeding with this test review the User Manual CH 48027-5 for Safety Information and Instructions.

  1. Install a fuel pressure gauge. Refer to «Fuel Pressure Gauge Installation and Removal (LE5)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) .
  2. Turn ON the ignition, with the engine OFF.
  3. Command the fuel pump relay ON with a scan tool.
  4. Observe the fuel pressure gauge with the fuel pump commanded ON. The fuel pressure should be 345-414 kPa (50-60 psi). If the fuel pressure is not within the specified range, refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  5. Monitor the fuel pressure gauge for one minute. The fuel pressure should not decrease more than 34 kPa (5 psi). If the fuel pressure decreases more than 34 kPa (5 psi), refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  6. Perform the Fuel Injector Balance Test with Special Tool, the Fuel Injector Balance Test with Tech 2, or the Fuel Injector Balance Test with the Active Fuel Injector Tester.
  1. Set the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5-2.5 A position.
  2. Connect the J 39021: Fuel Injector Coil and Balance Tester to a fuel injector using the J 44602: Adapter.
  3. Command the fuel pump relay ON and then OFF three times with a scan tool. On the last command, as the fuel pressure begins to slowly degrade and stabilize, select a fuel pressure within 34 kPa (5 psi) of the maximum pump pressure. Record this fuel pressure. This is the starting pressure at which you will pulse each injector.
  4. Command the fuel pump relay ON one more time and energize the fuel injector by depressing the Push to Start Test button on the J 39021: Fuel Injector Coil and Balance Tester at the previously selected pressure.
  5. After the injector stops pulsing, select Min from the Display Mode on the CH 48027: Gauge and record the Min pressure.
  6. Clear the Min/Max results on the CH 48027: Gauge.
  7. Select Normal from the Display Mode on the CH 48027: Gauge.
  8. Repeat steps 2 and 4 through 7 for each fuel injector.
  9. Subtract the minimum pressure from the starting pressure for one fuel injector. The result is the pressure drop value.
  10. Obtain a pressure drop value for each fuel injector.
  11. Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
  12. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 psi). If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 psi), replace the fuel injector.

Fuel Injector Balance Test with Scan Tool

  1. Command the fuel pump relay ON and then OFF three times with a scan tool. On the last command, as the fuel pressure begins to slowly degrade and stabilize, select a fuel pressure within 34 kPa (5 psi) of the maximum pump pressure. Record this fuel pressure. This is the starting pressure at which you will pulse each injector.
  2. With a scan tool, select the Fuel Injector Balance Test function within the Special Functions menu.
  3. Select an injector to be tested.
  4. Press Enter to prime the fuel system.
  5. Energize the fuel injector by depressing the Pulse Injector button on the scan tool at the previously selected pressure.
  6. After the injector stops pulsing, select Min from the Display Mode on the CH 48027: Gauge and record the Min pressure.
  7. Clear the Min/Max results on the CH 48027: Gauge.
  8. Select Normal from the Display Mode on the CH 48027: Gauge.
  9. Press Enter on the scan tool to bring you back to the Select Injector screen.
  10. Repeat steps 3 through 9 for each fuel injector.
  11. Subtract the minimum pressure from the starting pressure for one fuel injector. The result is the pressure drop value.
  12. Obtain a pressure drop value for each fuel injector.
  13. Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
  14. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 psi). If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 psi), replace the fuel injector.

Fuel Injector Balance Test with the Active Fuel Injector Tester

  1. Turn OFF all accessories.
  2. Turn OFF the ignition.
  3. Install the Active Fuel Injector Tester. Refer to the Active Fuel Injector Tester User Guide.
  4. Turn ON the Active Fuel Injector Tester and select the vehicle.
  5. Turn ON the ignition and perform the Injector Test. If the Active Fuel Injector Tester aborts testing due to fuel pressure or fuel leak down, refer to «Fuel System Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  6. View the test results. If any injector exceeds the recommended tolerance, replace the injector(s).

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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.

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. J 44175: Fuel Composition Tester
  2. J 44175-A: Fuel Composition Tester
  1. Observe the Fuel Composition Learn parameter using the scan tool. The Fuel Composition Learn parameter should display Inactive. IMPORTANT: 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. 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.
  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.
  4. Drive the vehicle until the Fuel Composition Learn parameter displays Inactive.
  5. Use the scan tool to reset the fuel trim values.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Test Description

Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust or deterioration.

Ethanol concentrations of greater than 10 percent in non-blended gasoline or greater than 85 percent with E85 blended gasoline for flexible fuel applications can cause driveability conditions such as hesitation, lack of power, stalling, or no start. Excessive concentrations of ethanol used in vehicles not designed for it may cause fuel system corrosion, deterioration of rubber components, and fuel filter restriction.

Special Tools

J 44175: Fuel Composition Tester

System Verification

The fuel sample should be drawn from the bottom of the tank so that any water present in the tank will be detected. The sample should be bright and clear.

  1. If the sample appears cloudy, or contaminated with water, as indicated by a water layer at the bottom of the sample, perform the Particulate Contaminants in Fuel Testing Procedure.
  2. If alcohol contamination is suspected, perform the Alcohol in Fuel Testing procedure.

Alcohol in Fuel Testing with Special Tool

  1. Test the fuel composition using J 44175: Tester and Instruction Manual.
  2. If water appears in the fuel sample, clean the fuel system.
  3. Subtract 50 from the reading on the DMM in order to obtain the percentage of alcohol in the fuel sample.
  4. If the non-blended gasoline fuel sample measures more than 15 percent ethanol, or if the E85 blended gasoline fuel sample measures more than 91 percent ethanol, add fresh regular gasoline to the vehicle's fuel tank.
  5. Test the fuel composition.
  6. If additional testing indicates that the ethanol percentage is still above 15 percent for a non-blended gasoline sample, drain and replace the vehicle's fuel. Refer to «Fuel Tank Draining (Non E-85)»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions) . If additional testing indicates that the E85 blended gasoline sample still measures above 91 percent, continue adding fresh, regular gasoline until the ethanol content is 85 percent or less.

Alcohol in Fuel Testing without Special Tool

  1. Using a 100 ml (3.38 oz) specified cylinder with 1 ml (0.034 oz) graduation marks, fill the cylinder with fuel to the 90 ml (3.04 oz) mark.
  2. Add 10 ml (0.34 oz) of water in order to bring the total fluid volume to 100 ml (3.38 oz) and install a stopper.
  3. Shake the cylinder vigorously for 10-15 seconds.
  4. Carefully loosen the stopper in order to release the pressure.
  5. Re-install the stopper and shake the cylinder vigorously again for 10-15 seconds.
  6. Put the cylinder on a level surface for approximately 5 minutes in order to allow adequate liquid separation. If alcohol is present in the fuel, the volume of the lower layer, which would now contain both alcohol and water, will be more than 10 ml (0.34 oz). For example, if the volume of the lower layer is increased to 15 ml (0.51 oz), this indicates at least 5 percent alcohol in the fuel. The actual amount of alcohol may be somewhat more because this procedure does not extract all of the alcohol from the fuel.

Particulate Contaminants in Fuel Testing Procedure

  1. Using an approved fuel container, draw approximately 0.5 liter (0.53 qt) of fuel.
  2. Place the container on a level surface for approximately 5 minutes in order to allow settling of the particulate contamination. Particulate contamination will show up in various shapes and colors. Sand will typically be identified by a white or light brown crystals. Rubber will appear as black and irregular particles.
  3. Observe the fuel sample. If any physical contaminants or water are present, clean the fuel system.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ignition system uses individual ignition coil/module assemblies for each cylinder. The engine control module (ECM) controls the individual coils by transmitting timing pulses on the ignition control (IC) circuit of each ignition coil/module to enable a spark event. Each ignition coil/module has the following circuits

  1. Ignition voltage
  2. Ground
  3. IC
  4. Low reference
  1. Depending on location in the spliced ignition voltage circuit, a slight resistance can cause a misfire or a crank/no start concern. A voltage drop test on the circuit will pinpoint this condition.
  2. A slight to moderate resistance on any IC circuit can cause a misfire before DTC P0351-P0354 sets.
  3. Extended engine cranking time, may foul the spark plugs with excessive fuel.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 26792 HEI Spark Tester. See Special Tools .

  1. Verify that the engine is in good mechanical condition before continuing with this diagnostic.
  2. Verify the following conditions: The ignition coil/modules are correctly connected The proper firing order The proper spark plug type The proper spark plug gap and torque Refer to «Ignition System Specifications»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-specifications__ignition-system-specifications) and «Spark Plug Inspection»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions__spark-plug-inspection) .
  1. Ignition OFF, disconnect the harness connector at the affected ignition coil/modules.
  2. Ignition OFF for 90 seconds, test for less than 5 ohms between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Test for less than 5 ohms between the low reference circuit terminal B and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal D and ground. If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance.
  5. Exchange the affected ignition coil/module with the ignition coil/module of a good cylinder.
  6. Start the engine, and observe the scan tool Misfire Current Cylinder parameters. If the misfire transfers with the suspect ignition coil/module, replace as needed.
  7. If the circuits test normal, test or replace the spark plug/s.

Use the J 26792 to verify the output of each ignition coil/module. See Special Tools .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Ignition Coil Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions)
  2. «Spark Plug Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-repair-instructions)

Operating Instructions for the Evaporative Emission System Tester (EEST)

Vehicle Setup

  1. Engine OFF, open the hood. Position a large fan to blow air under the vehicle onto the fuel tank area.
  2. Connect the red battery clip from the tester to the positive battery terminal.
  3. Connect the black battery clip from the tester to chassis ground.

Flowmeter Test - Leak Detection

  1. Open the Nitrogen tank valve and turn the NITROGEN/SMOKE valve on the front control panel to NITROGEN.
  2. Connect the hose to the correct test orifice on the bottom front of the tester. For orifice size, refer to the GM Service manual for the vehicle being tested. The vehicle specific information can be found in service procedures for DTCs that relate to evaporative emission (EVAP) system leaks.
  3. Press and release the remote switch to activate the tester.
  4. Position the sliding red flag on the flowmeter to align with the floating indicator. When the red flag is set, press and release the remote switch to deactivate the tester.
  5. Remove the hose from the test orifice and install the hose onto the vehicle. For proper connection location, and the special tool numbers for any adapters that may be required, refer to the service procedures for DTCs that relate to EVAP system leaks.
  6. Ignition ON, seal the EVAP system per instructions in the service procedures for DTCs that relate to EVAP system leaks. Most systems can be sealed using a scan tool output control for the EVAP canister vent solenoid valve, other systems require that the vent system be plugged.
  7. Press and release the remote switch to activate the nitrogen flow and fill the system.
  8. Compare the stable floating indicator position to the red flag. ABOVE the red flag, the result is UNACCEPTABLE, FAIL-Go to «Smoke Procedure - Locate the Leak»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis__smoke-procedure-locate-the-leak) . BELOW the red flag, the result is ACCEPTABLE, PASS-Test complete
  9. Press and release the remote switch to deactivate the tester.

Smoke Procedure - Locate the Leak

  1. Turn OFF any fans that may cause air movement around or near the vehicle.
  2. Connect the nitrogen/smoke hose to the vehicle as directed in the service procedures. Some vehicles require that the nitrogen/smoke hose be connected at the front of the EVAP system at the EVAP service port. An adapter may be necessary. Other vehicles require the connection be made at the rear of the system using an adapter at the fuel fill cap. Consult the service procedures for DTCs that relate to evaporative emission (EVAP) system leaks for vehicle specific instructions regarding connection location and adapters.
  3. Open the nitrogen tank valve and turn the NITROGEN/SMOKE valve on the control panel to SMOKE.
  4. Press and release the remote switch to activate the tester and inject smoke into the EVAP system.
  5. Verify smoke has filled the EVAP system by opening the system opposite the end where smoke is injected. When injecting smoke at the service port, remove the fuel fill cap, or temporarily leave the EVAP canister vent valve open, until smoke is observed. Then close the system and continue testing. If using a special tool fuel fill cap adapter at the filler neck, vent the system at the service port until smoke is observed then close the system to continue with the test.
  6. Press and release the remote switch to deactivate the tester.
  7. Introduce smoke into the system for an additional 60 seconds. Continue introducing smoke at 15-second intervals, as necessary.
  8. Using the a high-intensity white light, inspect the entire EVAP system path, and look for the source of the leak indicated by the exiting smoke. Introduce smoke at 15-second intervals, as needed, until leak source is identified.

The Concern

Ideal circumstances for conducting the EVAP Flowmeter Test require equal temperatures between the nitrogen gas and the vehicle EVAP system. Significant differences in temperature between them can result in a flow or pressure change during testing, causing misleading results. Typically, the Evaporative Emissions System Tester is stored indoors, approximately 21°C (70°F). Vehicles brought in for diagnosis may have an EVAP system at significantly different temperatures -40 to +43°C (-40 to +110°F).

For Example

Note. With no temperature difference between the nitrogen gas and EVAP system, the resulting vehicle EVAP system pressure will remain stable at 13 inches H2O once pressurized, providing no leaks are present.

When the EVAP Flowmeter Tests are performed with significant differences in temperature between the nitrogen gas and the vehicle EVAP system, the following results can occur

  1. An increase in flow during the flowmeter test can be caused by a vehicle's warm EVAP system cooling down.
  2. A decrease in flow during the flowmeter test can be caused by a vehicle's cool EVAP system warming up.

The Solution

When working on a vehicle with significant temperature differences between the vehicle EVAP system and the nitrogen gas, allow the vehicle EVAP system temperature to stabilize as close as possible to the temperature of the nitrogen gas before conducting the Flowmeter Test.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Several states require that a vehicle pass on-board diagnostic (OBD) system tests and the inspection/maintenance (I/M) emission inspection in order to renew license plates. This is accomplished by viewing the I/M System Status display on a scan tool. Using a scan tool, the technician can observe the I/M System Status in order to verify that the vehicle meets the criteria that complies with the local area requirements. While testing in the I/M System Status mode, some DTCs may occur that are called I/M Test DTCs. An I/M Test DTC is defined as a fault code that is currently commanding the MIL ON, and is stored in non-volatile memory. The intended use of this data is to prevent vehicles from passing I/M inspection without proper repair to the vehicle. These fault codes are not erasable from any scan tool command or erasable by disconnecting power to the controller. The I/M Test DTCs will be supported by all emissions related ECUs such as ECMs, TCMs, FPCMs, etc. An I/M Test DTC will not be stored or erased from the ECU except at the end of trip processing which occurs 5 s after ignition OFF.

Conditions for Updating the I/M System Status

Each system requires at least one, and sometimes several, diagnostic tests. The results of these tests are reported by a diagnostic trouble code (DTC). A system monitor is complete when either all of the DTCs comprising the monitor have Run and Passed, or any one of the DTCs comprising the monitor have illuminated the malfunction indicator lamp (MIL). Once all of the tests are completed, the I/M System Status display will indicate YES in the Completed column.

For example, when the HO2S Heater Monitor indicates YES, either all of the oxygen sensor heater tests have passed or one of the tests has illuminated the MIL. If the vehicle has four heated oxygen sensors, either all four heater circuit tests have passed or one of the heater circuit tests has illuminated the MIL. The I/M System Status will indicate NO under the Completed column when any of the required tests for that system have not run. The following is a list of conditions that would set the I/M System Status indicator to NO

  1. The vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
  2. The battery has been disconnected or discharged below operating voltage.
  3. The control module power or ground has been interrupted.
  4. The control module has been reprogrammed.
  5. The control module DTCs have been cleared as part of a service procedure.

Conditions for Clearing I/M Test DTCs

  1. Only the OBD II System can erase the I/M Test DTC. The OBD II system must determine that the malfunction that caused the I/M Test DTC to be stored is no longer present and is not commanding the MIL. Each of the following represents ways to clear an I/M Test DTC: If the MIL goes out due to 3 passing drive cycles, scan tool code clear is not used, the I/M Test DTC is erased at power down of the last drive cycle. If a scan tool code clear is used to turn OFF the MIL, the I/M Test DTC is not erased, the DTC must PASS and not FAIL. The I/M Test DTC is erased at power down of the drive cycle. If the controller is reflashed/reprogrammed, all I/M Test DTCs are erased.
  2. For the OBD II System to run a single drive cycle for clearing an I/M Test DTC, all of the following conditions must occur: Cumulative time of engine run time is greater than 600 s. Cumulative vehicle operation above 40 km/h (25 mph) for over 300 s. Continuous vehicle idle for greater than 30 s. Turn ignition OFF for 5 s and allow the code to clear.

Monitored Emission Control Systems

The OBD II system monitors all emission control systems that are on-board. Not all vehicles need every possible emission control system. For example, a vehicle may not be equipped with secondary air injection (AIR) or exhaust gas recirculation (EGR). The OBD II regulations require monitoring of the following; if equipped

  1. The air conditioning system
  2. The catalytic converter efficiency
  3. Comprehensive component monitoring-Emission related inputs and outputs
  4. The evaporative emission (EVAP) system
  5. The fuel delivery system
  6. Heated catalyst monitoring
  7. Misfire monitoring
  8. The oxygen sensor system (O2S or HO2S)
  9. The oxygen sensor heater system (HO2S heater)

For the specific DTCs required for each system, refer to Inspection/Maintenance System DTC Table . Systems such as misfire and comprehensive components may not be listed in a system status list. These tests run continuously and do not require an I/M System Status indicator.

The I/M System Status display provides an indication of when the control module has completed the required tests. This does not necessarily mean that the test has passed, only that a decision was made. If the diagnostic fails, a DTC will indicate the failure. If a failure indication is present for a DTC associated with one of the I/M regulated systems, it may prevent other required tests from running. For example, a DTC for the control circuit of the EVAP purge solenoid may not be listed in the Inspection/Maintenance System DTC Table because it is a continuous test. If this DTC is set, the Active Tests for the EVAP system may not run.

The I/M System Status information may be useful for a technician to determine if diagnostics have run when verifying repairs.

Review the I/M System Status indicators. All I/M System Status indicators should report YES, and no I/M Test DTCs should be present.

  1. Observe the Engine DTC information with a scan tool. Verify no DTCs are present. If a DTC is set that would prevent the I/M System Status tests from completing, diagnose that DTC before continuing. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Review applicable service bulletins for software updates that would prevent the I/M System Status tests from completing. If a control module re-program or other repair is required, perform the «Inspection/Maintenance Complete System Set Procedure»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  3. Observe the I/M System Status indicators. If any I/M System Status indicators report NO, perform the «Inspection/Maintenance Complete System Set Procedure»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  4. Observe the I/M Test DTC information with a scan tool. Verify there are no I/M Test DTCs present. If an I/M Test DTC is set and all of the I/M System Status indicators are Yes, there is no need to perform the Complete System Set Procedure. Diagnose the DTC using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) and refer to Conditions for Clearing the I/M Test DTCs. If an I/M Test DTC is set and the I/M System Status indicators are NO, diagnosis the DTC and perform the «Inspection/Maintenance Complete System Set Procedure»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The purpose of the Inspection/Maintenance Complete System Set Procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics and complete the drive cycles for those particular diagnostics. When all I/M monitored diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform the Inspection/Maintenance Complete System Set Procedure if any I/M System Status indicators are set to NO.

Inspection/Maintenance Data List

To determine if the inspection/maintenance readiness diagnostic tests can be run this ignition cycle, use a scan tool to observe the inspection/maintenance monitor enabled parameters in the inspection/maintenance Data List.

Conditions for Meeting a Cold Start

  1. The ignition voltage between 11-18 V.
  2. The barometric pressure is more than 75 kPa (10.9 psi).
  3. The start-up engine coolant temperature is between 4-30°C (39-86°F).
  4. The start-up intake air temperature is between 4-30°C (39-86°F).
  5. The difference between the IAT and the ECT is less than or equal to 6°C (43°F).
  6. The ambient air temperature is between 4-30°C (39-86°F).
  7. The fuel level is between 15-85 %.

Review the inspection/maintenance system status indicators with a scan tool. All I/M system status indicators should report YES, and no I/M Test DTCs should be present.

Inspection/Maintenance System Set Procedure

  1. Ensure that the vehicle meets the conditions for a cold start listed above.
  2. The evaporative emission inspection/maintenance system status indicator should display YES. If the inspection/maintenance system status indicator displays NO, perform the Service Bay Test, if applicable. If the Service Bay Test is NOT available, it may take up to 6 drive cycles, with up to 17 h between drive cycles, for the inspection/maintenance system status indicator to transition to YES.
  3. The O2S Heater inspection/maintenance system status indicator should display YES. If the O2S Heater inspection/maintenance system status indicator displays NO, ensure that the ignition has been turned OFF for at least 10 h.
  4. Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc.
  5. Set the vehicle parking brake and ensure the vehicle is in Park for automatic transmission or Neutral for manual transmission.
  6. Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc.
  7. Start and idle the engine for at least 2 min and until 65°C (149°F) is achieved.
  8. Run the engine for 6.5 min within the following conditions: MAF parameter between 4-30 g/s Engine speed steady between 1,000-3,000 RPM
  9. Return the engine to idle for 1 minute.
  10. Apply and hold the brake pedal, and shift to Drive for automatic transmission, or apply the clutch pedal for manual transmission and operate the vehicle within the following conditions for 2 min: Depress the accelerator pedal until throttle position sensor angle is more than 2 %. Mass air flow signal between 15-30 g/s RPM steady between 1,200-2,000 RPM
  11. Release the accelerator pedal and shift the vehicle to Park for automatic transmission, or Neutral and release the clutch pedal for manual transmission, and allow the engine to idle for 2 min.
  12. Quickly depress the accelerator pedal until throttle position sensor angle is more than 8 % and return to idle, repeat 3 times.
  13. Allow engine to idle for at least 2 min.
  14. Release the parking brake and drive vehicle at 24 km/h (15 mph) or slower for 2 min.
  15. Continue to drive the vehicle for at least 5.5 mi between 45-112 km/h (28-70 mph) with the vehicle reaching at least 80 km/h (50 mph).
  16. Release the accelerator pedal for at least 2 s. This will allow the vehicle to enter decel fuel cut-off.
  17. Depress the accelerator pedal until the throttle position sensor angle is increased 3-20 % and maintain a safe speed for 1 min.
  18. Safely stop the vehicle, with the engine in Drive for automatic transmission or in Neutral with the clutch pedal depressed and parking brake applied for manual transmission, idle for 2 min.
  19. Shift to Park for automatic and apply the parking brake, or neutral and release clutch pedal for manual.
  20. Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 60 min.
  21. Observe the Inspection/Maintenance System Status with a scan tool. All of the Inspection/Maintenance System Status indicators should display YES. If the evaporative emission Inspection/Maintenance System Status indicator displays NO, turn OFF the ignition for 17 h, ensure that the vehicle meets the conditions for a cold start, and repeat steps 12-18 six more times, or until the evaporative emission Inspection/Maintenance System Status indicator transitions to YES. If the indicator continues to display NO, refer to the «Inspection/Maintenance System DTC Table»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis__inspectionmaintenance-system-dtc-table) to identify the DTCs that did not run. Follow the Conditions for Running the DTC in order to set the evaporative emission Inspection/Maintenance System Status indicator If any of the Inspection/Maintenance System Status display NO, refer to the «Inspection/Maintenance System DTC Table»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis__inspectionmaintenance-system-dtc-table) for the indicator which did not display YES. The Inspection/Maintenance System DTC Table identifies the DTCs associated with each Inspection/Maintenance System Status Indicator. Follow the Conditions for Running the DTC in order to set the associated status indicator.
  22. Observe the I/M Test DTC information with a scan tool. Verify there are no I/M Test DTCs present. If an I/M Test DTC is set, diagnose the DTC using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) and refer to «Inspection/Maintenance System Check»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) for clearing I/M Test DTCs. If an I/M Test DTC is set and the I/M System Status indicators are NO, diagnosis the DTC and perform the «Inspection/Maintenance Complete System Set Procedure»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) .
  23. Observe the engine DTC information with a scan tool. Verify no DTCs are present. If a DTC is set, diagnose using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . After repairs, perform the «Inspection/Maintenance Complete System Set Procedure»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-24l-troubleshooting-and-diagnosis) to verify no further DTCs are set.

Inspection/Maintenance System DTC Table

SystemDTCs Required to Set System Status to YES
Catalyst Monitor If an I/M System Status indicator did NOT update to YES during the Inspection/Maintenance System Check , review each indicator and reference this table to determine each DTC associated with the I/M System Status Indicator. Each DTC listed below has specific conditions that must be met for the diagnostic to run. Included in these conditions are additional DTCs which, if set, will inhibit these DTCs from running. Reviewing and operating the vehicle within the Conditions for Running for each DTC listed below will allow the I/M System Status Indicators to transition to YES.
CatalystDTC P0420
EVAPDTC P0442 DTC P0446 DTC P0451-P0454 DTC P0455 DTC P0496
Oxygen SensorDTC P0133, P0134, P013A, P013B, P013E, P013F, P0140, P1133, P2270, P2271, or P2A00
Oxygen Sensor HeaterDTC P0030, P0036, P0053, P0054, P0135, or P0141
Secondary AIR InjectionDTC P2430-P2433 DTC P2440 DTC P2444 DTC P0411
Camshaft SystemDTC P0011 or P0014

Poor Fuel Fill Quality

ProblemCauses
DEFINITION: During the fueling process a continual, occasional or no fuel nozzle shut-off condition has occurred.
Difficult to fillFuel fill limiter vent valve stuck closed Evaporative emission (EVAP) canister restricted EVAP vent valve stuck closed Hose between canister and canister vent solenoid twisted or kinked if applicable High fuel temperature Fuel filler hose is kinked Faulty dispensing nozzle Ignition switch ON, vent valve closed
Over fillFill limiter vent valve stuck open or leaking Fuel inlet check valve stuck open
Pre-mature shut-off of the fuel dispensing nozzle occurs immediately after engaging dispensing nozzle, tank emptyRestricted vapor lines or fuel fill pipe High fuel temperature Inlet check valve at tank stuck closed, fill pipe full of fuel Fuel tank full, gauge not accurate
Pre-mature shut-off of the fuel dispensing nozzle, more than 1/8 of tank capacity dispensedKinked, pinched or plugged lines in fuel tank vent system EVAP vent valve stuck closed or restricted EVAP canister restricted Fuel limiting vent valve stuck closed or obstruction at top of fuel tank
Fuel SpitbackRestricted EVAP canister High fuel temperature Ignition switch ON, EVAP vent valve closed

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Control Module References
• Spark Plug Inspection
• Ignition System Specifications
• Coolant in Combustion Chamber
• Oil Consumption Diagnosis
• Torque Converter Diagnosis
• DTC P0171 or P0172
• Heated Oxygen and Oxygen Sensor Caution
• Mass Airflow Sensor with Intake Air Temperature Sensor Replacement
• Symptoms - Engine Exhaust
• Crankcase Ventilation System Inspection/Diagnosis (Without Turbocharger)
• Thermostat Diagnosis
• Loss of Coolant
• Throttle Body Cleaning
• Temperature Versus Resistance
• Crankshaft and Bearing Cleaning and Inspection
• Symptoms - Engine Electrical
• Camshaft Actuator System Description
• Engine Control Module Scan Tool Information (2.4L)
• Engine Overheating
• Engine Mount Inspection
• Diagnostic Procedure Instructions
• Instrument Cluster Schematics
• Engine Controls Schematics (LAT)
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Diagnostic Repair Verification
• Road Test Warning
• Battery Inspection/Test
• Engine Cranks Slowly
• Diagnostic Trouble Code (DTC) List - Vehicle
• Restricted Exhaust
• Engine Compression Test
• Relay Replacement (Attached to Wire Harness)
• Fuel Pressure Relief (without CH 48027-100)
• Special Tools
• Fuel System Cleaning
• DTC P0420
• Fuel System Diagnosis
• Fuel Injector Balance Test - Fuel Pressure Test
• AFIT Test Procedure
• Smoke Procedure - Locate the Leak
• Inspection/Maintenance System DTC Table

More articles — Engine Performance