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Diagnostic Item 1: Communication with no ECUs is possible (CAN-C).
 
 
cautionWhen servicing a CAN bus line, ground yourself by touching a metal object such as an unpainted water pipe. If you fail to do, a component connected to the CAN bus line may be broken.
 
 
TROUBLESHOOTING HINTS
  • Malfunction in CAN-C (short to ground or power supply, wire short to one another)
  • Malfunction in the ECUs which are interconnected via CAN-C (internal error)
  • Malfunction (open circuit) of wiring harness, connector (s) between the data link connector and joint connector(s)
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the CAN-C for short to power supply. Voltage measurement at data link connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Connect the negative 12V starter battery terminal, and turn on the power supply mode of the electric motor switch.
(2) Voltage between data link connector terminal No.6 (CAN_H) and body ground
OK: Less than 4.0 V
(3) Voltage between data link connector terminal No.14 (CAN_L) and body ground
OK: Less than 4.0 V
Is the check result normal?
: Go to Step 2.
: Perform diagnostic item 2 "Diagnose shorts in the power supply to CAN-C". Refer to .
 
STEP 2. Check the CAN-C for short to ground. Resistance measurement at data link connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Turn off the power supply mode of the electric motor switch.
(2)
cautionWhen measuring the resistance, disconnect the negative 12V starter battery terminal. For details refer to .
Ensure that the negative 12V starter battery terminal is disconnected.
(3) Resistance between data link connector terminal No.6 (CAN_H) and body ground
OK: 1 kΩ or more
(4) Resistance between data link connector terminal No.14 (CAN_L) and body ground
OK: 1 kΩ or more
Is the check result normal?
: Go to Step 3.
: Perform diagnostic item 3 "Diagnose shorts in the ground to CAN-C". Refer to .
 
STEP 3. Check the CAN-C for short to each other. Resistance measurement at data link connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Turn off the power supply mode of the electric motor switch.
(2)
cautionWhen measuring the resistance, disconnect the negative 12V starter battery terminal. For details refer to .
Ensure that the negative 12V starter battery terminal is disconnected.
(3) Resistance between data link connector terminal Nos.6 and 14
OK: 60 ± 10 ohms
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 ).
: Perform diagnostic Item 4 "Diagnose shorts between CAN_H and L lines (CAN-C)". Refer to .
: Check the wires between data link connector and joint connector (CAN3) for open circuit, and check the terminal resistors in the engine control module and the ETACS-ECU for open circuit. Then repair or replace if necessary.