Diagnosis Item 9: Diagnose when the M.U.T.-III cannot receive the data sent by ETACS-ECU.


caution
  • When servicing a CAN bus line, earth 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 .)

FUNCTION


The diagnostic result demonstrates that "the M.U.T.-III cannot receive the sent data from the ETACS-ECU" when the M.U.T.-III checks the periodically sent data from each ECU and cannot receive the ETACS-ECU data only.

TROUBLE JUDGEMENT CONDITIONS


M.U.T.-III judges the trouble when the periodically sent data from ETACS-ECU cannot be received.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Connector check: joint connector (CAN3) <LHD> or joint connector (CAN4) <RHD> and ETACS-ECU connector
caution The 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.

Q. Is the check result normal?
Go to Step 2.
Repair the defective connector. Replace the joint connector as necessary.

STEP 2. Resistance measurement at joint connector (CAN3) <LHD> or joint connector (CAN4) <RHD> and ETACS-ECU connector.
caution A digital multimeter should be used. For details refer to .
caution The test wiring harness should be used. For details refer to .
(1)Disconnect the joint connector (CAN3) <LHD> or joint connector (CAN4) <RHD> and the ETACS-ECU connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the LOCK (OFF) position.
(3)
caution When measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4)Continuity between joint connector (CAN3) terminal No.11 and ETACS-ECU connector terminal No.19 <LHD>
OK: Continuity (2 Ω or less)
(5)Continuity between joint connector (CAN3) terminal No.22 and ETACS-ECU connector terminal No.18 <LHD>
OK: Continuity (2 Ω or less)
(6)Continuity between joint connector (CAN4) terminal No.7 and ETACS-ECU connector terminal No.19 <RHD>
OK: Continuity (2 Ω or less)
(7)Continuity between joint connector (CAN4) terminal No.18 and ETACS-ECU connector terminal No.18 <RHD>
OK: Continuity (2 Ω or less)
caution Strictly observe the specified wiring harness repair procedure. For details refer to .

Q. Is the check result normal?
<All the resistances measure 2 Ω or less> Go to Step 3 .
NO : <Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN3) <LHD> or joint connector (CAN4) <RHD> and the ETACS-ECU connector.

STEP 3. Resistance measurement at ETACS-ECU connector.
caution A digital multimeter should be used. For details refer to .
(1)Remove the ETACS-ECU, and measure at the equipment side.
(2)Resistance at ETACS-ECU connector terminal Nos.18 and 19
OK: 120 ± 20 Ω

Q. Is the check result normal?
<Within 120 ± 20 Ω> Power supply to the ETACS-ECU may be suspected. Diagnose the ETACS. Refer to GROUP 54A ETACS - Troubleshooting Refer to .
<Not within 120 ± 20 Ω> Replace the ETACS-ECU.