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Diagnostic Item 34: Diagnose when the scan tool (M.U.T.-IIISE) cannot receive the data sent by TCU. <Vehicles with TCU (20 Model year)>
 
 
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.
 
 
FUNCTION
The diagnostic result demonstrates that "the scan tool (M.U.T.-IIISE) cannot receive the sent data from the TCU" when the scan tool (M.U.T.-IIISE) checks the periodically sent data from each ECU and cannot receive the TCU data only.
 
 
TROUBLE JUDGMENT CONDITIONS
The scan tool (M.U.T.-IIISE) judges the trouble when the periodically sent data from TCU cannot be received.
 
 
TROUBLESHOOTING HINTS
  • Damaged harness wires and connectors
  • Power supply circuit malfunction of the TCU
  • Malfunction of the TCU
  • Malfunction of the gateway-ECU (for TCU)
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Connector check: gateway-ECU (for TCU) connector and TCU connector.
cautionThe strand end of the twist wire should be within 10 cm (3.9 inches) from the connector. For details refer to .
Is the check result normal?
Go to Step 2.
Repair the defective connector. Replace the connector as necessary.
 
STEP 2. Resistance measurement at gateway-ECU (for TCU) connector and TCU connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the gateway-ECU (for TCU) connector and the TCU 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 auxiliary battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Continuity between gateway-ECU (for TCU) connector terminal No.6 and TCU connector terminal No.33
OK: The resistance should be 2 ohms or less
(5) Continuity between gateway-ECU (for TCU) connector terminal No.5 and TCU connector terminal No.13
OK: The resistance should be 2 ohms or less
Is the check result normal?
<All the resistances measure 2 ohms or less> Go to Step 3.
: <Either or all of the resistances measure more than 2 ohms> Repair the intermediate connector C-253, or wiring harness between gateway-ECU (for TCU) connector and the TCU connector.
 
STEP 3. Resistance measurement at gateway-ECU (for TCU) connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the gateway-ECU (for TCU), and measure at the equipment side.
(2) Resistance at gateway-ECU (for TCU) connector terminal Nos.6 and 5
OK: 120 ± 20 ohms
Is the check result normal?
<Within 120 ± 20 ohms> Go to Step 4.
<Not within 120 ± 20 ohms> Replace the gateway-ECU (for TCU).
 
STEP 4. Resistance measurement at TCU connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the TCU, and measure at the equipment side.
(2) Resistance at TCU connector terminal Nos.33 and 13
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> Replace the TCU.