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Home >> Mitsubishi >> 2012 >> Lancer AWD L4-2.0L Turbo (4B11T) >> 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:
Whenever the CAN box unit is replaced, ensure that the power supply circuit and the grounding circuit are normal. (Check that the voltage is 10 V or more.)


















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.

TROUBLESHOOTING HINTS

- 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-108 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is CAN box unit connectors C-108 in good condition?

YES Go to Step 2.
NO Repair or replace the damaged component(s). Harness Connector Inspection.
STEP 2. Check the ground circuit to the CAN box unit. Measure the resistance at CAN box unit connector C-108.

(1)Disconnect CAN box unit connector C-108 and measure the resistance available at the wiring harness side of the connector.





(2)Measure the resistance value between CAN box unit connector C-108 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-108
(terminal 1) and the ground.

- Check the ground wire for open circuit.

NOTE:
Also check intermediate connector C-105 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-105 is damaged, repair or replace the connector as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between CAN box unit connector C-108 (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-108.

(1)Disconnect CAN box unit connectors C-108 measure the voltage available at the wiring harness side of the connector.





(2)Measure the voltage between CAN box unit connector C-108 terminal 2 and ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Q. Is the measured voltage approximately 12 volts (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-108
(terminal 2) and fusible link (36).

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

NOTE:
Also check intermediate connector C-105, C-128, C-39 and ETACS-ECU connectors C-307 and C-311 for loose, corroded, or damaged terminals, or terminals pushed back in the connector.
If intermediate connector C-105, C-128, C-39 and ETACS-ECU connectors C-307 and C-311 is damaged, repair or replace the connector as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between CAN box unit connector C-108 (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.
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 Inspection Procedure 1."
STEP 7. Check ETACS-ECU connector C-313 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is ETACS-ECU connector C-313 in good condition?

YES Go to Step 8.
NO Repair or replace the damaged component(s). Harness Connector Inspection.
STEP 8. Check the battery power supply circuit to the CAN box unit.
Measure the voltage at CAN box unit connectors C-108.

(1)Disconnect CAN box unit connectors C-108 measure the voltage available at the wiring harness side of the connector.





(2)Measure the voltage between CAN box unit connector C-108 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-108
(terminal 10) and ETACS-ECU connector C-313 (terminal 1).

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

NOTE:
Also check intermediate connector C-105, C-128, C-39 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-105, C-128, C-39 is damaged, repair or replace the connector as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between CAN box unit connectors C-108 (terminal 10) and ETACS-ECU connector C-313 (terminal 1) 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.
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