Toyota Sienna Service Manual: How to proceed with troubleshooting

NOTICE: DTCs for the CAN communication system are as follows: U0073, U0100, U0122, U0123, U0124, U0126 and U1101.

HINT: If U0235 or U1102 is output alone, the CAN communication is normal

1 CHECK AND CLEAR DTCS

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 or 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.

2 CHECK FOR INSTALLED SYSTEMS (ECUS & SENSORS) THAT ADOPT CAN COMMUNICATION)

1. Check which of the following is adopted: brake control system and dynamic laser cruise control system

3 CHECK WITH INTELLIGENT TESTER

1. Using the intelligent tester, display the "Communication Bus Check" screen (See page CA-17).
2. Observe the screen for approximately 1 minute to check the ECUs and sensors displayed on the screen.

Result

NOTICE: Non-installed ECUs or sensors will not be displayed.

Do not mistake them for being in the communication stop mode.

HINT: The ECUs and sensors that repeatedly appear and disappear from the screen during this check are considered normal. (The response to the intelligent tester and the tester display are affected by signals output from other ECUs which have an open circuit in either of their CAN branch wires.)

4 CHECK CAN BUS WIRE

1. Check the CAN bus wires (See page CA-35).

HINT: If the area where an open or short is occurring in a CAN bus wire can be determined, refer to the "PROBLEM SYMPTOMS TABLE"

5 DTC COMBINATION TABLE

1. Confirm trouble according to the combination of output DTCs regarding the CAN communication system

6 CIRCUIT INSPECTION

7 IDENTIFICATION OF PROBLEM

8 REPAIR OR REPLACE

9 CONFIRMATION TEST

END