Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMITSUBISHI2009LANCER L4-2.4L (4B12)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSTESTING AND INSPECTIONSYMPTOM RELATED DIAGNOSTIC PROCEDURESINSPECTION PROCEDURE 13
2009 Mitsubishi Lancer L4-2.4L (4B12)
Inspection Procedure 13
2009 Mitsubishi Lancer L4-2.4L (4B12)SECTION Inspection Procedure 13
Inspection procedure 13: The engine stalls decelerating
COMMENT
- Abnormal air/fuel ratio or other similar defects due to insufficient intake air volume and defective EGR system is suspected to be the causes.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the ignition system.
- Malfunction of the purge control system.
- Malfunction of the EGR system.
- Malfunction of the ECM.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Check if the EGR valve sounds during initialization.
Q: Is the initialization sound heard in the EGR valve?
YES : Go to Step 2.
NO : Refer to EGR Valve (Stepper Motor) Check. [1][2]Component Tests and General Diagnostics
STEP 2. Using scan tool MB991958, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Read the DTC.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?
YES : Refer to Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
NO : Go to Step 3.
STEP 3. Engine stall reproduction test.
Q: Does the engine stall during the decrease in engine speed after running?
YES : Go to Step 5.
NO : Go to Step 4.
STEP 4. Using scan tool MB991958, check actuator test.
1. Turn the ignition switch to the "ON" position.
2. Check the following item in the actuator test. Refer to Actuator Test Reference Table. Actuator Test Reference Table
a. Item 10: Evaporative Emission Purge Solenoid.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES : Go to Step 5.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 5. Using scan tool MB991958, check data list.
1. Turn the ignition switch to the "ON" position.
2. Check the following items in the data list. Refer to Data List Reference Table. Datal List Reference Table
a. Item 13: Throttle Position Sensor (main).
b. Item 15: Throttle Position Sensor (sub).
c. Item 11: Accelerator Pedal Position Sensor (main).
d. Item 12: Accelerator Pedal Position Sensor (sub).
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?
YES : Go to Step 6.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 6. Check the spark plugs.
Refer to On-vehicle Service - Spark Plug Check. Testing and Inspection
Q: Are there any abnormalities?
YES : Replace the spark plug. Then confirm that the malfunction symptom is eliminated.
NO : Check the ignition coil. Refer to Ignition System-Then confirm that the malfunction symptom is eliminated.
COMMENT
- Abnormal air/fuel ratio or other similar defects due to insufficient intake air volume and defective EGR system is suspected to be the causes.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the ignition system.
- Malfunction of the purge control system.
- Malfunction of the EGR system.
- Malfunction of the ECM.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Check if the EGR valve sounds during initialization.
Q: Is the initialization sound heard in the EGR valve?
YES : Go to Step 2.
NO : Refer to EGR Valve (Stepper Motor) Check. [1][2]Component Tests and General Diagnostics
STEP 2. Using scan tool MB991958, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Read the DTC.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?
YES : Refer to Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
NO : Go to Step 3.
STEP 3. Engine stall reproduction test.
Q: Does the engine stall during the decrease in engine speed after running?
YES : Go to Step 5.
NO : Go to Step 4.
STEP 4. Using scan tool MB991958, check actuator test.
1. Turn the ignition switch to the "ON" position.
2. Check the following item in the actuator test. Refer to Actuator Test Reference Table. Actuator Test Reference Table
a. Item 10: Evaporative Emission Purge Solenoid.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES : Go to Step 5.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 5. Using scan tool MB991958, check data list.
1. Turn the ignition switch to the "ON" position.
2. Check the following items in the data list. Refer to Data List Reference Table. Datal List Reference Table
a. Item 13: Throttle Position Sensor (main).
b. Item 15: Throttle Position Sensor (sub).
c. Item 11: Accelerator Pedal Position Sensor (main).
d. Item 12: Accelerator Pedal Position Sensor (sub).
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?
YES : Go to Step 6.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 6. Check the spark plugs.
Refer to On-vehicle Service - Spark Plug Check. Testing and Inspection
Q: Are there any abnormalities?
YES : Replace the spark plug. Then confirm that the malfunction symptom is eliminated.
NO : Check the ignition coil. Refer to Ignition System-Then confirm that the malfunction symptom is eliminated.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.