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Diagnostic Item 12: Diagnose shorts between CAN_H and L lines (CAN-C-Mid).
 
 
caution
  • When 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.
  • When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine cannot be started. Register the encrypted code as described in GROUP 54A, Immobilizer System - How to Register Key ID .)
 
 
TROUBLE JUDGMENT
When all of the following conditions are met, the scan tool (M.U.T.-III) determines that a short circuit is present between CAN_L and CAN_H lines.
  • The scan tool (M.U.T.-III) cannot receive the periodic transmission data from any ECUs.
  • The voltage between CAN-C-Mid (CAN_L and CAN_H lines) is 1.0 V or more, 4.0 V or less.
  • The resistance at CAN-C-Mid (CAN_L and CAN_H lines) is 2 ohms or less.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the wiring harness
  • Malfunction of the connector
  • Malfunction of the ETACS-ECU
  • Malfunction of the heater controller assembly (A/C-ECU)
  • Malfunction of the KOS-ECU <Vehicles with KOS>
  • Malfunction of the OSS-ECU <Vehicles with OSS>
  • Malfunction of the radio and CD player <Vehicles with 1CD audio or display audio>
  • Malfunction of the multivision display <Vehicles with smartphone link display audio>
  • Malfunction of the camera-ECU <Vehicles with multi around monitor>
  • Malfunction of the power liftgate control unit <Vehicles with power liftgate>
  • Malfunction of the combination meter
 
 
DIAGNOSIS
STEP 1. Connector check: joint connector (CAN5)
cautionThe strand end of the twist wire should be within 10 cm from the connector. For details refer to .
When checking the joint connector, ensure that its wiring harness side and its short pins are not damaged.
Is the check result normal?
Go to Step 2
Repair a defective connector or replace the joint connector.
 
STEP 2. Resistance measurement at joint connector (CAN5).
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.11 and 22
OK: 120 ± 20 ohms
Is the check result normal?
<Within 120 ± 20 ohms> Go to Step 4.
: <Not within 120 ± 20 ohms> Go to Step 3.
 
STEP 3. Resistance measurement at ETACS-ECU connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the ETACS-ECU, and measure at the equipment side.
(2) Resistance between ETACS-ECU connector terminal Nos.16 and 17
OK: 120 ± 20 ohms
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<Within 120 ± 20 ohms> Repair the wiring harness between joint connector (CAN5) and the ETACS-ECU connector.
<Not within 120 ± 20 ohms> Check the ETACS-ECU connector, and repair if necessary. If the ETACS-ECU connector is in good condition, replace the ETACS-ECU.
 
STEP 4. Resistance measurement at joint connector (CAN5).
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.6 and 17
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 6.
<Less than 1 kΩ> Go to Step 5.
 
STEP 5. Resistance measurement at A/C-ECU connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the A/C-ECU, and measure at the equipment side.
(2) Resistance between A/C-ECU connector terminal Nos.31 and 32
OK: 1 kΩ or more
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint connector (CAN5) and the A/C-ECU connector.
<Less than 1 kΩ> Check the A/C-ECU connector, and repair if necessary. If the A/C-ECU connector is in good condition, replace the A/C-ECU.
 
STEP 6. Resistance measurement at joint connector (CAN5).
noteSteps 6 and 7 are only for vehicles with power liftgate. On vehicles without it, go to Step 8.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.8 and 19
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 8.
<Less than 1 kΩ> Go to Step 7.
 
STEP 7. Resistance measurement at power liftgate control unit connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the power liftgate control unit, and measure at the equipment side.
(2) Resistance between power liftgate control unit connector terminal Nos.7 and 8
OK: 1 kΩ or more
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Check the intermediate connector, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN5) and the power liftgate control unit connector.
<Less than 1 kΩ> Check the power liftgate control unit connector, and repair if necessary. If the power liftgate control unit connector is in good condition, replace the power liftgate control unit.
 
STEP 8. Resistance measurement at joint connector (CAN5).
noteSteps 8 and 9 are only for vehicles with multi around monitor. On vehicles without it, go to Step 10.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.4 and 15
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 10.
<Less than 1 kΩ> Go to Step 9.
 
STEP 9. Resistance measurement at camera-ECU connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the camera-ECU, and measure at the equipment side.
(2) Resistance between camera-ECU connector terminal Nos.1 and 21
OK: 1 kΩ or more
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint connector (CAN5) and the camera-ECU connector.
<Less than 1 kΩ> Check the camera-ECU connector, and repair if necessary. If the camera-ECU connector is in good condition, replace the camera-ECU.
 
STEP 10. Resistance measurement at joint connector (CAN5).
noteSteps 10 and 11 are only for vehicles with 1CD audio or display audio. On vehicles without it, go to Step 12.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.7 and 18
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 12.
<Less than 1 kΩ> Go to Step 11.
 
STEP 11. Resistance measurement at radio and CD player connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the radio and CD player, and measure at the equipment side.
(2) Resistance at radio and CD player connector terminal Nos.3 and 13
OK: 1 kΩ or more
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint connector (CAN5) and the radio and CD player connector.
<Less than 1 kΩ> Check the radio and CD player connector, and repair if necessary. If the radio and CD player connector is in good condition, replace the radio and CD player.
 
STEP 12. Resistance measurement at joint connector (CAN5).
noteSteps 12 and 13 are only for vehicles with smartphone link display audio. On vehicles without it, go to Step 14.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.7 and 18
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 14.
<Less than 1 kΩ> Go to Step 13.
 
STEP 13. Resistance measurement at multivision display connector <Vehicles with smartphone link display audio>.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the multivision display <Vehicles with smartphone link display audio>, and measure at the equipment side.
(2) Resistance at multivision display connector <Vehicles with smartphone link display audio> terminal Nos.3 and 13
OK: 1 kΩ or more
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint connector (CAN5) and the multivision display connector <Vehicles with smartphone link display audio>.
<Less than 1 kΩ> Check the multivision display connector <Vehicles with smartphone link display audio>, and repair if necessary. If the multivision display connector <Vehicles with smartphone link display audio> is in good condition, replace the multivision display <Vehicles with smartphone link display audio>.
 
STEP 14. Resistance measurement at joint connector (CAN5).
noteSteps 14 and 15 are only for vehicles with OSS. On vehicles without it, go to Step 16 .
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.10 and 21
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 16.
<Less than 1 kΩ> Go to Step 15.
 
STEP 15. Resistance measurement at OSS-ECU connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the OSS-ECU, and measure at the equipment side.
(2) Resistance at OSS-ECU connector terminal Nos.1 and 14
OK: 1 kΩ or more
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint connector (CAN5) and the OSS-ECU connector.
<Less than 1 kΩ> Check the OSS-ECU connector, and repair if necessary. If the OSS-ECU connector is in good condition, replace the OSS-ECU.
 
STEP 16. Resistance measurement at joint connector (CAN5).
noteSteps 16 and 17 are only for vehicles with KOS. On vehicles without it, go to Step 18 .
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.5 and 16
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 18.
<Less than 1 kΩ> Go to Step 17.
 
STEP 17. Resistance measurement at KOS-ECU connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the KOS-ECU, and measure at the equipment side.
(2) Resistance at KOS-ECU connector terminal Nos.3 and 2
OK: 1 kΩ or more
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<1 kΩ or more> Repair the wiring harness between joint connector (CAN5) and the KOS-ECU connector.
<Less than 1 kΩ> Check the KOS-ECU connector, and repair if necessary. If the KOS-ECU connector is in good condition, replace the KOS-ECU.
 
STEP 18. Resistance measurement at joint connector (CAN5).
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect joint connector (CAN5), and measure at the wiring harness side.
(2) Turn the ignition switch to the LOCK (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Resistance between joint connector (CAN5) terminal Nos.9 and 20
OK: 120 ± 20 ohms
Is the check result normal?
<Within 120 ± 20 ohms> The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
<Not within 120 ± 20 ohms> Go to Step 19.
 
STEP 19. Resistance measurement at combination meter connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the combination meter, and measure at the equipment side.
(2) Resistance at combination meter connector terminal Nos.14 and 15
OK: 120 ± 20 ohms
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<Within 120 ± 20 ohms> Repair the wiring harness between joint connector (CAN5) and the combination meter connector.
<Not within 120 ± 20 ohms> Check the combination meter connector, and repair if necessary. If the combination meter connector is in good condition, replace the combination meter.