How To Proceed With Troubleshooting

Standard voltage: 11 to 14 V 

HINT:

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

HINT:

• CAN communication DTCs are output 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, the sensor itself also cause these DTCs to be output.
• If a CAN communication wire connector is disconnected with the ignition switch on (IG), the ECUs of the corresponding system and related systems record a DTC.

1. Based on the vehicle equipment and specifications, confirm the systems that use CAN communication (See DIAGNOSIS SYSTEM  ).

HINT:

Operating the ignition 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.

1. Turn the ignition switch off.
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION TABLE
   
   

   Tester Connection	Condition	Result	Proceed to
   D47-6 (CANH) - D47-14 (CANL)	Ignition switch off	54 to 69 Ω	A
   D47-6 (CANH) - D47-14 (CANL)	Ignition switch off	70 Ω or higher	B
   D47-6 (CANH) - D47-14 (CANL)	Ignition switch off	Below 54 Ω	C

   Fig 1: Identifying DLC3 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

B: GO TO CAN MAIN WIRE FOR DISCONNECTION  (See OPEN IN CAN MAIN BUS LINE  )

C: GO TO CHECK CAN BUS LINES FOR SHORT CIRCUIT  (See CHECK CAN BUS LINES FOR SHORT CIRCUIT  )

A: Go to next step 

1. Turn the ignition switch off.
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION TABLE
   
   

   Tester Connection	Condition	Specified Condition
   D47-6 (CANH) - D47-4 (CG)	Ignition switch off	200 Ω or higher
   D47-14 (CANL) - D47-4 (CG)	Ignition switch off	200 Ω or higher

   Fig 2: Identifying DLC3 Connector Terminals CG, CANH & CANL

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: GO TO CHECK CAN BUS LINE FOR SHORT TO GND  (See CHECK CAN BUS LINE FOR SHORT TO GND  )

OK: Go to next step 

1. Disconnect the negative battery terminal.
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION TABLE
   
   

   Tester Connection	Condition	Specified Condition
   D47-6 (CANH) - D47-16 (BAT)	Disconnect negative battery terminal	6 kΩ or higher
   D47-14 (CANL) - D47-16 (BAT)	Disconnect negative battery terminal	6 kΩ or higher

   Fig 3: Identifying DLC3 Connector Terminals CANH, BAT & CANL

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: GO TO CHECK CAN BUS LINE FOR SHORT TO +B  (See CHECK CAN BUS LINE FOR SHORT TO +B  )

OK: Go to next step 

1. Using Techstream, display the "Communication Bus Check" screen (See DIAGNOSIS SYSTEM  ).
2. Observe the screen for approximately 1 minute to check the ECUs and sensors displayed on the screen.

   Result 

   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
   One of the ECUs and sensors connected to the CAN communication system is not displayed on the screen. (Open in ECU or sensor branch wires, or communication interrupted)	B(*1)
   Some ECUs and sensors repeatedly appear and disappear from the screen, during this check. (Open in one side of ECU or sensor branch wires)	C
   All ECUs and sensors except the main body ECU connected to the CAN MS bus are not displayed on the screen. The main body ECU outputs DTC U1002. (Open in CAN MS bus main wire or short in CAN MS bus wire)	D
   All ECUs and sensors connected to the CAN MS bus are not displayed on the screen. (Open in main body ECU branch wire or main body ECU malfunction)	E
   HINT: (*1): See the "DTC TABKE" instead of the "COMMUNICATION STOP MODE TABLE" when some of the ECUs connected to the CAN MS bus are not displayed on the screen (See DIAGNOSIS SYSTEM  ). The ECUs connected to the CAN MS bus are displayed on the screen by the main body ECU.

   NOTE:

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

B: GO TO "COMMUNICATION STOP MODE TABLE"  (See PROBLEM SYMPTOMS TABLE  )

C:  GO TO OPEN IN ONE SIDE OF CAN BRANCH WIRE 

D: GO TO "U1002 (CAN MS BUS)"  (See DTC U1002 (CAN MS BUS) LOST COMMUNICATION WITH GATEWAY MODULE (MAIN BODY ECU)  )

E:  GO TO MAIN BODY ECU COMMUNICATION STOP MODE 

A: Go to next step 

HINT:

• Sometimes CAN communication system DTCs are output, but all the ECUs and sensors connected to the CAN communication system are displayed on 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. The communication stop mode in the CAN bus can be determined by comparing the combination of DTCs that have been set. Refer to the DTC combination table for the CAN bus.
• The main body ECU will store communication error DTCs when the ECUs connected to the CAN MS bus cannot communicate, or if a network malfunction occurs.

Result 

B: GO TO "U1002 (CAN MS BUS)"  (See DTC U1002 (CAN MS BUS) LOST COMMUNICATION WITH GATEWAY MODULE (MAIN BODY ECU)  )

C: GO TO "DTC TABLE"  (See DIAGNOSTIC TROUBLE CODE TABLE  )

A: Go to next step 

1. Confirm trouble according to the combination of output DTCs regarding the CAN communication system (See 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 Techstream's "Communication Bus Check" screen.

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