2018 / ECLIPSE CROSS / EC - Workshop Manual
36 -PARKING BRAKE > TROUBLESHOOTING<ELECTRIC PARKING BRAKE><ELECTRIC PARKING BRAKE> > SYMPTOM PROCEDURES > M.U.T.-III CANNOT COMMUNICATE WITH THE ELECTRIC PARKING BRAKE SYSTEM (POWER SUPPLY CIRCUIT FOR THE ELECTRIC PARKING BRAKE ECU FAILS).
Inspection Procedure 1: M.U.T.-IIISE cannot communicate with electric parking brake system (the power supply to the electric parking brake ECU fails).
| caution | - If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table
 ). - Whenever ECU is replaced, ensure that the CAN bus lines are normal.
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COMMENTS ON TROUBLE SYMPTOM
When M.U.T.-IIISE cannot communicate with the electric parking brake system, the CAN bus lines, electric parking brake ECU power supply circuit system, earth, or electric parking brake ECU may be faulty.
PROBABLE CAUSES
- Open or earth fault in the electric parking brake ECU power supply circuit, or defective connector(s)
- Malfunction of the electric parking brake ECU
DIAGNOSIS PROCEDURE
STEP 1. Measure the resistance at the electric parking brake ECU connector.
(1) Disconnect the connector and measure at the wiring harness side.
(2) Measure the resistance between GND1 terminal and body earth.OK: Continuity exists (2 Ω or less).
(3) Measure the resistance between GND2 terminal and body earth.OK: Continuity exists (2 Ω or less).
Is the check result normal?
Go to Step 2.
The earth circuit may be open. Repair the wiring harness wires or connectors between the electric parking brake ECU connector and the body earth.
STEP 2. Measure the voltage at the electric parking brake ECU connector.
(1) Disconnect the electric parking brake ECU connector.
(2) Measure the voltage between the +ECU terminal and body earth.OK: Battery voltage
Is the check result normal?
Go to Step 3. The power supply circuit may be open. Repair the wiring harness wires or connectors between the electric parking brake ECU connector and the fusible link.
STEP 3. Measure the voltage at the electric parking brake ECU connector.
(1) Disconnect the electric parking brake ECU connector and measure at the wiring harness side.
(2) Turn the ignition switch to the ON position.
(3) Measure the voltage between the IG1 terminal and body earth.OK: Battery voltage
Is the check result normal?
Go to Step 4. The IG1 signal circuit may be open or short to earth. Repair the wiring harness wires or connectors between the electric parking brake ECU connector and the ETACS-ECU (IG1 relay).
STEP 4. Retest the system
