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Inspection Procedure 11: Cannot communicate with EV remote-ECU using the M.U.T.-IIISE.
 
 
cautionBefore replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
TECHNICAL DESCRIPTION (COMMENT)
If scan tool (M.U.T.-IIISE) cannot communicate with the EV remote-ECU, the CAN bus lines may be faulty. If the EV remote-ECU does not work, the EV remote-ECU or its power supply circuit may be faulty.
 
 
TROUBLESHOOTING HINTS
  • The power supply and the ground of EV remote-ECU may be defective
  • The CAN bus line may be defective
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Press the electric motor switch to turn on the power supply mode.
(3) Diagnose the CAN bus line.
(4) Press the electric motor switch to turn off the power supply mode.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ).
 
STEP 2. Voltage measurement at EV remote-ECU connector (IG1, +B) terminal.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Press the electric motor switch to turn the power supply mode from "OFF" to "ON."
(3) Check the voltage between the EV remote-ECU connector IG1 terminal and ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage)
Check the voltage between the EV remote-ECU connector +B terminal and ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage)
Is the check result normal?
Go to Step 4.
Go to Step 3.
 
STEP 3. Check of short to power supply, short to ground, and open circuit in (IG1, +B) line between fusible link and EV remote-ECU connector.
Is the check result normal?
Go to Step 4.
Repair the power supply circuit to EV remote-ECU.
 
STEP 4. Resistance measurement at EV remote-ECU connector (GND terminal)
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the EV remote-ECU connector (GND terminal) and ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 6.
Go to Step 5.
 
STEP 5. Check of open circuit in GND line between EV remote-ECU connector and ground.
Is the check result normal?
Go to Step 6.
Repair the ground circuit to EV remote-ECU.
 
STEP 6. Retest the system.
Check if scan tool (M.U.T.-IIISE) can communicate with EV remote-ECU.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).
: Replace the EV remote-ECU (Refer to ).