How To Proceed With Troubleshooting

HINT: 

*: Use the Techstream.

1. VEHICLE BROUGHT TO WORKSHOP 

   NEXT: Go to next step 

2. CUSTOMER PROBLEM ANALYSIS 
   1. Interview the customer and confirm the problem.

      NEXT: Go to next step 

3. CHECK BATTERY 

   Standard Voltage

   11 to 14 V

   HINT: 

   If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step.

   NEXT: Go to next step 

4. CHECK AND CLEAR DTCS* 

   HINT: 

   • CAN communication DTCs are stored when there is an open or short in any of the communication wires. Any problems with the power source of a corresponding ECU or sensor, or problems in the ECU or the sensor itself also cause these DTCs to be stored.
   • If a CAN communication wire connector is disconnected with the power switch on (IG), the ECUs of the corresponding system and related systems store a DTC.

   NEXT: Go to next step 

5. CHECK FOR DLC3 BRANCH WIRE AND V1 MAIN BUS WIRE (CANH - CANL) 
   NOTE:

   • Turn the power switch off before measuring the resistances between CAN main bus wires and between CAN bus branch wires.
   • Turn the power switch off before inspecting CAN bus wires for a ground short.
   • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.
   • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

   HINT: 

   • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
   • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.
   1. Turn the power switch off.
      Fig 1: Identifying L61 (CANH & CANL) Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection	Switch Condition	Specified Condition
      L61-6 (CANH) - L61-14 (CANL)	Power switch off	54 to 69 Ω

      TEXT IN ILLUSTRATION
      
      

      *1

      DLC3

      Result

      Result	Proceed to
      OK	A
      NG (70 Ω or higher)	B
      NG (Below 54 Ω)	C

      B → GO TO OPEN IN CAN MAIN BUS WIRE. Refer to Open in CAN Main Bus Line 

      C → GO TO SHORT IN CAN BUS LINES. Refer to Check CAN Bus Lines for Short Circuit 

      A: Go to next step 

6. CHECK FOR SHORT TO GND IN V1 BUS (CANH, CANL - CG) 
   1. Turn the power switch off.
      Fig 2: Identifying L61 (CANH, CANL - CG) Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection	Switch Condition	Specified Condition
      L61-6 (CANH) - L61-4 (CG)	Power switch off	200 Ω or higher
      L61-14 (CANL) - L61-4 (CG)	Power switch off	200 Ω or higher

      TEXT IN ILLUSTRATION
      
      

      *1

      DLC3

      NG → GO TO SHORT TO GND IN CAN BUS WIRE. Refer to Check CAN Bus Line for Short to GND 

      OK: Go to next step 

7. CHECK FOR SHORT TO +B IN V1 BUS (CANH, CANL - BAT) 
   1. Disconnect the cable from the negative (-) battery terminal.
      Fig 3: Identifying L61 (CANH, CANL - BAT) Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection	Condition	Specified Condition
      L61-6 (CANH) - L61-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher
      L61-14 (CANL) - L61-16 (BAT)	Cable disconnected from negative (-) battery terminal	6 kΩ or higher

      TEXT IN ILLUSTRATION
      
      

      *1

      DLC3

      NG → GO TO SHORT TO +B IN CAN BUS WIRE. Refer to Check CAN Bus Line for Short to +B 

      OK: Go to next step 

8. CHECK INSTALLED SYSTEMS (ECU AND SENSOR) THAT USE CAN COMMUNICATION 
   1. Based on the vehicle equipment and specifications, confirm the systems that use CAN communication. Refer toDIAGNOSIS SYSTEM .

      NEXT: Go to next step 

9. CHECK ECUS CONNECTED TO CAN BUS* 
   1. Select "CAN Bus Check" from the screen on the Techstream. Refer toDIAGNOSIS SYSTEM .
   2. Observe the screen for approximately 1 minute to check the ECUs and sensors displayed on the screen.

      Result

      Result	Proceed to
      All ECUs and sensors connected to the CAN communication system are displayed on the screen. (CAN bus circuit is currently normal.)	A
      All ECUs except the power management control ECU connected to the V2 bus are not displayed on the screen. The power management control ECU (power management1) outputs DTC U1002. (Open or short in V2 main bus wires.)	B
      All ECUs except the power management control ECU connected to the power management bus are not displayed on the screen. The power management control ECU (power management2) outputs DTC U1002. (Open or short in power management main bus wires.)	C
      All ECUs connected to the V2 bus and power management bus are not displayed on the screen. (Open in power management control ECU branch wires or power management control ECU malfunction.)	D
      One of the ECUs and sensors connected to the V1 bus is not displayed on the screen. (Open in ECU or sensor branch wires, or communication interrupted.)	E
      One of the ECUs and sensors connected to the V2 bus or power management bus is not displayed on the screen. (Open in ECU or sensor branch wires, or communication interrupted.)	F
      Some ECUs and sensors repeatedly appear and disappear on the screen during this check. (Open in one side of ECU or sensor branch wires.)	G

      NOTE:

      • The systems (ECUs and sensors) that adopt CAN communication vary depending on the vehicle and optional equipment. Check which systems (ECUs and sensors) are installed on the vehicle. Refer toDIAGNOSIS SYSTEM .
      • Non-installed ECUs or sensors will not be displayed. Do not mistake them for being in communication stop mode.
      • The ECUs and sensors that repeatedly appear and disappear from the screen during this check are considered normal. (The response to the Techstream and its display are affected by signals output from other ECUs which have an open circuit in either of their CAN bus branch wires.)

      HINT: 

      The ECUs connected to the V2 bus and power management bus are displayed on the screen by the power management control ECU.

      B → GO TO U1002 (POWER MANAGEMENT1). Refer to DTC U1002: Lost Communication with Gateway Module (Power Management1) 

      C → GO TO U1002 (POWER MANAGEMENT2). Refer to DTC U1002: Lost Communication with Gateway Module (Power Management2) 

      D → GO TO POWER MANAGEMENT CONTROL ECU COMMUNICATION STOP MODE. Refer to Power Management Control ECU Communication Stop Mode 

      E → GO TO COMMUNICATION STOP MODE TABLE. Refer to PROBLEM SYMPTOMS TABLE  

      F → GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to DIAGNOSTIC TROUBLE CODE CHART  

      G → GO TO OPEN IN ONE SIDE OF CAN BRANCH LINE. Refer to Open in One Side of CAN Branch Line 

      A: Go to next step 

10. RECHECK DTC 

    HINT: 

    • Sometimes CAN communication system DTCs are output, but all ECUs and sensors connected to the CAN communication system are displayed on the Techstream. In this case, previous or history DTCs may indicate the cause of the problem.
    • ECUs related to a problem in the CAN bus will store DTCs to indicate communication malfunctions. Communication stop mode in the CAN bus can be determined by comparing the combination of DTCs that have been set. Refer to  11DTC Combination Table for the CAN bus.
    • The power management control ECU will store communication error DTCs when the ECUs connected to the V2 bus and power management bus cannot communicate, or if a network malfunction occurs.

    Result

    Result	Proceed to
    Communication error DTCs other than the codes output from the power management control ECU are output. (A malfunction occurred in the V1 bus.)	A
    The power management control ECU (Power Management1) outputs DTC U1002. (A malfunction occurred in the V2 bus.)	B
    The power management control ECU (Power Management2) outputs DTC U1002. (A malfunction occurred in the power management bus.)	C
    The power management ECU outputs DTCs other than DTC U1002. (A malfunction occurred in an ECU branch wire connected to the V2 bus or power management bus.)	D

    B → GO TO U1002 (POWER MANAGEMENT1). Refer to  DTC U1002: Lost Communication with Gateway Module (Power Management1) 

    C → GO TO U1002 (POWER MANAGEMENT2). Refer to  DTC U1002: Lost Communication with Gateway Module (Power Management2) 

    D → GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART  

    A: Go to next step 

11. DTC COMBINATION TABLE 
    1. Confirm trouble according to the combination of output DTCs regarding the CAN communication system. Refer to DIAGNOSIS SYSTEM .

       HINT: 

       Previous CAN communication system DTCs may be the cause if CAN communication system DTCs are output and all ECUs and sensors connected to the CAN communication system are displayed on "CAN Bus Check" of the Techstream.

       NEXT: Go to next step 

12. CIRCUIT INSPECTION 

    NEXT: Go to next step 

13. IDENTIFICATION OF PROBLEM 

    NEXT: Go to next step 

14. REPAIR OR REPLACEMENT 

    NEXT: Go to next step 

15. CONFIRMATION TEST* 

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