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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 DIAGNOSISBODY AND FRAMEBODY CONTROL SYSTEMSTESTING AND INSPECTIONSYMPTOM RELATED DIAGNOSTIC PROCEDURESWIRELESS CONTROL MODULE (WCM)INSPECTION PROCEDURE 4
2009 Mitsubishi Lancer L4-2.4L (4B12)
Inspection Procedure 4
2009 Mitsubishi Lancer L4-2.4L (4B12)SECTION Inspection Procedure 4
Inspection Procedure 4: Abnormality in WCM power supply and ground circuits.
CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
TECHNICAL DESCRIPTION (COMMENT)
If the WCM does not work at all or if the WCM cannot communicate with the scan tool, the WCM power supply or the ground circuit may be defective.
TROUBLESHOOTING HINTS
- Damaged wiring harness and connectors
- Malfunction of the WCM
DIAGNOSIS
Required Special Tools:
- MB992006: Extra fine probe
- MB991223: Harness set
STEP 1. Check WCM connector C-09 and ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is the WCM connector C-09 and ETACS-ECU connector C-317 in good condition?
YES: Go to Step 2.
NO: Repair the defective connector.
STEP 2. Check the wiring harness between WCM connector C-09 (terminal No.6, 9) and the ETACS-ECU connector C-317 (terminal No.10, 5) for open circuit.
1. Disconnect WCM connector C-09 and ETACS-ECU connector C-317, and check the wiring harness.
2. Check the wiring harness between WCM connector C-09 (terminal No.6) and ETACS-ECU connector C-317 (terminal No.10)
OK: Continuity exists (2 ohms or less)
3. Check the wiring harness between WCM connector C-09 (terminal No.9) and ETACS-ECU connector C-317 (terminal No.5)
OK: Continuity exists (2 ohms or less)
Q: Is the wiring harness between WCM connector C-09 and the ETACS-ECU connector C-317 in good condition?
YES: Go to Step 3.
NO: Repair the wiring harness between WCM connector C-09 (terminal No.6, 9) and ETACS-ECU connector C-317 (terminal No.10, 5).
STEP 3. Check the wiring harness between the WCM connector C-09 (terminal No.7) and the ground for open circuit.
1. Disconnect the connector and measure the resistance at the wiring harness side.
2. Turn the ignition switch to the ON position.
3. Measure the resistance between terminal No.7 and the ground.
OK: Continuity exists (2 ohms or less)
Q: Is the wiring harness between WCM connector C-09 and the ground in good condition?
YES: Go to Step 4.
NO: Repair the wiring harness between WCM connector C-09 (terminal No.7) and ground.
STEP 4. Retest the system
Q: Does the abnormality in WCM power supply and ground circuits in good condition?
YES: The trouble can be an intermittent malfunction.
NO: Replace WCM and register the ID codes.
CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
WCM Power Supply Circuit (Part 1):
WCM Power Supply Circuit (Part 2):
TECHNICAL DESCRIPTION (COMMENT)
If the WCM does not work at all or if the WCM cannot communicate with the scan tool, the WCM power supply or the ground circuit may be defective.
TROUBLESHOOTING HINTS
- Damaged wiring harness and connectors
- Malfunction of the WCM
DIAGNOSIS
Required Special Tools:
- MB992006: Extra fine probe
- MB991223: Harness set
STEP 1. Check WCM connector C-09 and ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is the WCM connector C-09 and ETACS-ECU connector C-317 in good condition?
YES: Go to Step 2.
NO: Repair the defective connector.
STEP 2. Check the wiring harness between WCM connector C-09 (terminal No.6, 9) and the ETACS-ECU connector C-317 (terminal No.10, 5) for open circuit.
1. Disconnect WCM connector C-09 and ETACS-ECU connector C-317, and check the wiring harness.
2. Check the wiring harness between WCM connector C-09 (terminal No.6) and ETACS-ECU connector C-317 (terminal No.10)
OK: Continuity exists (2 ohms or less)
3. Check the wiring harness between WCM connector C-09 (terminal No.9) and ETACS-ECU connector C-317 (terminal No.5)
OK: Continuity exists (2 ohms or less)
Q: Is the wiring harness between WCM connector C-09 and the ETACS-ECU connector C-317 in good condition?
YES: Go to Step 3.
NO: Repair the wiring harness between WCM connector C-09 (terminal No.6, 9) and ETACS-ECU connector C-317 (terminal No.10, 5).
STEP 3. Check the wiring harness between the WCM connector C-09 (terminal No.7) and the ground for open circuit.
1. Disconnect the connector and measure the resistance at the wiring harness side.
2. Turn the ignition switch to the ON position.
3. Measure the resistance between terminal No.7 and the ground.
OK: Continuity exists (2 ohms or less)
Q: Is the wiring harness between WCM connector C-09 and the ground in good condition?
YES: Go to Step 4.
NO: Repair the wiring harness between WCM connector C-09 (terminal No.7) and ground.
STEP 4. Retest the system
Q: Does the abnormality in WCM power supply and ground circuits in good condition?
YES: The trouble can be an intermittent malfunction.
NO: Replace WCM and register the ID codes.
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.