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Home >> Mitsubishi >> 2010 >> Lancer Evolution L4-2.0L Turbo (4B11T/C) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Inspection Procedure 12

Inspection Procedure 12

INSPECTION PROCEDURE 12: Check The CAN Box Unit Power Supply Circuit.

CAUTION: Before replacing the CAN box unit, ensure that the power supply circuit, the ground circuit and the communication circuit are normal. (Check that the voltage is 10 V or more.)


CAN Box Unit Power Supply Circuit (Part 1):




CAN Box Unit Power Supply Circuit (Part 2):






TECHNICAL DESCRIPTION (COMMENT)
If the CAN box unit functions do not work at all, the CAN box unit power supply system, ground system, or CAN box unit may have a problem.

PROBABLE CAUSES
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The CAN box unit may be defective

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958 Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827 M.U.T.-III USB Cable
- MB991910 M.U.T.-III Main Harness A

STEP 1. Check CAN box unit connectors C-15 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is CAN box unit connectors C-15 in good condition?

YES : Go to Step 2.

NO : Repair or replace the damaged component(s).

STEP 2. Check the ground circuit to the CAN box unit. Measure the resistance at CAN box unit connector C-15.

1. Disconnect CAN box unit connector C-15 and measure the resistance available at the wiring harness side of the connector.







2. Measure the resistance value between CAN box unit connector C-15 terminal 1 and ground.

OK: The resistance should be 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 4.

NO : Go to Step 3.

STEP 3. Check the wiring harness between CAN box unit connector C-15 (terminal 1) and the ground.

- Check the ground wires for open circuit.

NOTE: Also check intermediate connector C-108 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-108 is damaged, repair or replace the connector.

Q: Is the wiring harness between CAN box unit connector C-15 (terminal 1) and the ground in good condition?

YES : Go to Step 4.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

STEP 4. Check the battery power supply circuit to the CAN box unit. Measure the voltage at CAN box unit connectors C-15.

1. Disconnect CAN box unit connectors C-15 measure the voltage available at the wiring harness side of the connector.







2. Measure the voltage between CAN box unit connector C-15 terminal 2 and ground.

OK:Battery positive voltage.

Q: Is the measured voltage battery positive voltage?

YES : Go to Step 6.

NO : Go to Step 5.

STEP 5. Check the wiring harness between CAN box unit connector C-15 (terminal 2) and fusible link (36).

- Check the power supply line for open circuit and short circuit.

NOTE: Also check intermediate connector C-108 and ETACS-ECU connectors C-307 and C-317 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-108 or ETACS-ECU connector C-307 or C-317 is damaged, repair or replace the connector.

Q: Is the wiring harness between CAN box unit connector C-15 (terminal 2) and fusible link (36) in good condition?

YES : Go to Step 6.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The system should communicate with the CAN box unit normally.

STEP 6. Using scan tool MB991958, check data list.

Check the input signal of ACC relay.
- Turn the ignition switch to the ACC position.







OK: Normal condition is displayed.

Q: Is the check result normal?

YES : Go to Step 7.

NO : Refer to ETACS, Diagnosis - Inspection Procedure 1 "The ignition switch (ACC) signal is not received." Inspection Procedure 1

STEP 7. Check ETACS-ECU connector C-315 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-315 in good condition?

YES : Go to Step 8.

NO : Repair or replace the damaged component(s).

STEP 8. Check the battery power supply circuit to the CAN box unit. Measure the voltage at CAN box unit connectors C-15.

1. Disconnect CAN box unit connectors C-15 measure the voltage available at the wiring harness side of the connector.







2. Measure the voltage between CAN box unit connector C-15 terminal 10 and ground.

OK:Battery positive voltage.

Q: Is the measured voltage battery positive voltage?

YES : Replace the CAN box unit.

NO : Go to Step 9.

STEP 9. Check the wiring harness between CAN box unit connectors C-15 (terminal 10) and ETACS-ECU connector C-315 (terminal 9).

- Check the power supply line for open circuit and short circuit.

NOTE: Also check intermediate connector C-108 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-108 is damaged, repair or replace the connector.

Q: Is the wiring harness between CAN box unit connectors C-15 (terminal 10) and ETACS-ECU connector C-315 (terminal 9) in good condition?

YES : No action is necessary and testing is complete.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The system should communicate with the CAN box unit normally.
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