Diagnostic Item 27: Diagnose When The Scan Tool (M.U.T.-IIISE) Cannot Receive The Data Sent By HUD. <Vehicles With HUD>: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Connector check: joint connector (CAN5) and HUD connector 
   CAUTION: The strand end of the twist wire should be within 10 cm (3.9 inches) from the connector. For details Refer to TEST EQUIPMENT .

   When checking the joint connector, ensure that its wiring harness side and its short pins are not damaged.

   Q: Is the check result normal? 

   YES  : Go to Step 2.

   NO  : Repair the defective connector. Replace the joint connector as necessary.

2. STEP 2. Resistance measurement at joint connector (CAN5) and HUD connector. 
   CAUTION: A digital multimeter should be used. For details Refer to TEST EQUIPMENT .
   CAUTION: The test wiring harness should be used. For details Refer to TEST EQUIPMENT .
   1. Disconnect joint connector (CAN5) and the HUD connector, and measure at the wiring harness side.
   2. Turn the ignition switch to the "LOCK" (OFF) position.
      CAUTION: When measuring the resistance, disconnect the negative battery terminal. For details Refer to TEST EQUIPMENT .
   3. Ensure that the negative battery terminal is disconnected.
   4. Continuity between joint connector (CAN5) terminal No. 5 and HUD connector terminal No. 6

      OK: The resistance should be 2 ohms or less 

   5. Continuity between joint connector (CAN5) terminal No. 16 and HUD connector terminal No. 18

      OK: The resistance should be 2 ohms or less 

   CAUTION: Strictly observe the specified wiring harness repair procedure. For details Refer to TEST EQUIPMENT .

   Q: Is the check result normal? 

   YES  : <All the resistances measure 2 ohms or less> Go to Step 3.

   NO  : <Either or all of the resistances measure more than 2 ohms> Repair the wiring harness between joint connector (CAN5) and the HUD connector.

3. STEP 3. Resistance measurement at HUD connector. 
   CAUTION: A digital multimeter should be used. For details Refer to TEST EQUIPMENT .
   1. Remove the HUD, and measure at the equipment side.
   2. Resistance between HUD connector terminal Nos.6 and 18

      OK: 1 kΩ or more 

   Q: Is the check result normal? 

   YES  : Power supply to the HUD may be suspected. Diagnose the HUD. Refer to SYMPTOM CHART .

   NO  : Replace the HUD.