How To Proceed With Troubleshooting

NOTE:

DTCs for the CAN communication system are as follows: U0001, U0073, U0100, U0104, U0110, U0122, U0123, U0124, U0126, U0129, U0130, U0131, U0132, U0146, U0235, U0293, U1101, and U1102
Refer to the troubleshooting procedures of each system if DTCs regarding the CAN communication system are not output.
Before measuring the resistance, leave the vehicle for at least 1 minute and do not operate the ignition switch, any switches or doors. If doors need to be opened in order to check connectors, open the doors and leave them open.

HINT:

*: Use the intelligent tester.
Operating the power switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

VEHICLE BROUGHT TO WORKSHOP
INSPECT BATTERY VOLTAGE
Standard voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the battery before proceeding.
CHECK AND CLEAR DTC*
1. Using the intelligent tester, perform the ALL DTC check.
  NOTE:
  - If a CAN communication malfunction code that informs that an ECU or sensor has a power malfunction or interior malfunction is causing a communication stop, the problem may not be in the communication line. There is a high possibility that the ECU or sensor has a signal transmission failure. Therefore, first troubleshoot any DTCs related to the ECU or sensor.
  - When CAN communication related connectors are disconnected with the power switch ON (IG or ACC), the ECU related to the connector and ECUs of related systems will store a CAN communication DTC.
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 (see DIAGNOSIS SYSTEM ).

CHECK ECUS CONNECTED TO CAN BUS*

Select "BUS CHECK" from the "OBD/MOBD MENU" screen (see DIAGNOSIS SYSTEM ).
Press "ENTER" on the intelligent tester (see DIAGNOSIS SYSTEM ).

Wait 1 minute and then check the display of the connected ECUs and sensors.

RESULT REFERENCE CHART

Inspection Result	Proceed to
No ECUs or sensors are displayed (CAN No. 1 bus circuit main wire open or short malfunction, or DLC3 branch wire malfunction)	A
Except for hybrid vehicle control ECU, no ECUs connected to CAN No. 2 bus circuit are displayed (CAN No. 2 bus circuit main wire open or short malfunction)	B
No ECUs connected to CAN No. 2 bus circuit are displayed (branch wire between hybrid vehicle control ECU and CAN No. 1 bus circuit is open)	C
ECU or sensor that should be connected to CAN communication is not displayed (ECU or sensor branch wire open)	D
ECU or sensor that should be connected to CAN communication is not displayed or display is intermittent during check (ECU or sensor branch wire open on one side)	E
All ECUs and sensors connected to CAN communication are displayed (CAN bus circuit normal)	F

NOTE:

ECUs and sensors that are not present will not be displayed. Be careful not to mistaken them for communication stop malfunctions.

HINT:

If the display of an ECU is intermittent during the check, one side of an ECU or sensor branch wire is open. (The signal of the ECU is treated as noise, which affects the response and display of the intelligent tester.)
The hybrid vehicle control ECU checks for proper ECU communication for ECUs that are connected to the CAN No. 2 bus circuit, and the results are displayed on the intelligent tester. If communication stops between an ECU and hybrid vehicle control ECU for 10 seconds or more, the ECU disappears from the intelligent tester display.
For communication stop mode of ECUs connected to the CAN No. 2 bus circuit, refer to the DTC flowchart of the respective communication stop.

B: GO TO DTC U1003 FLOWCHART

C: GO TO HYBRID VEHICLE CONTROL ECU COMMUNICATION STOP MODE FLOWCHART

D: GO TO PROBLEM SYMPTOMS TABLE

E: GO TO OPEN IN ONE SIDE OF CAN BRANCH WIRE FLOWCHART

F: GO TO step 9

A: GO TO Next Step

CHECK DLC3 BRANCH WIRE AND CAN NO. 1 BUS CIRCUIT MAIN WIRE (CANH - CANL)

Measure the resistance of the DLC3.

Fig 1: Identifying DLC3 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Condition	Specified Condition	Proceed to
6 (CANH) - 14 (CANL)	Power switch off	OK (54-69 Ω)	A
6 (CANH) - 14 (CANL)	Power switch off	NG (70 Ω or more)	B
6 (CANH) - 14 (CANL)	Power switch off	NG (less than 54 Ω)	C

B: GO TO CAN MAIN WIRE FOR DISCONNECTION

C: GO TO CHECK CAN BUS LINES FOR SHORT CIRCUIT

A: GO TO Next Step

CHECK CAN NO. 1 BUS CIRCUIT +B (BAT - CANH, CANL)

Measure the resistance of the DLC3.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Condition	Specified Condition
6 (CANH) - 16 (BAT)	Power switch off	6 kΩ or more
14 (CANL) - 16 (BAT)	Power switch off	6 kΩ or more

Fig 2: Identifying DLC3 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: GO TO 1CHECK CAN BUS LINE FOR SHORT TO +B

OK: GO TO Next Step

CHECK CAN NO. 1 BUS CIRCUIT GND (CG - CANH, CANL)

Measure the resistance of the DLC3.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

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

Fig 3: Identifying DLC3 Connector Terminals

NG: GO TO 1CHECK CAN BUS LINE FOR SHORT TO GND

OK: GO TO Next Step

CHECK COMMUNICATION MALFUNCTION DTC (PAST DTC CHECK)*

Select "BUS CHECK" from the "OBD/MOBD MENU" screen (see DIAGNOSIS SYSTEM ).
Press "ENTER" on the intelligent tester (see DIAGNOSIS SYSTEM ).

Write down all of the DTCs stored in each ECU.

HINT:

If there are communication malfunction DTCs stored but the intelligent tester's "Bus Check-Communication Bus Check" screen displays all of the ECUs and sensors connected to the CAN system, the communication malfunction DTCs may be past malfunctions that are no longer present.
For CAN No. 1 bus circuit main wire malfunctions, related ECUs are also detected. Therefore, determine the malfunctioning area based on all of the DTCs that are output.
For CAN No. 2 bus circuit malfunctions, DTCs are output based on the detection of communication stop malfunctions of ECUs that are connected by the hybrid vehicle control ECU.
During a network malfunction (main wire malfunction), the hybrid vehicle control ECU may erase stored DTCs in an attempt to reinstate communication.

For DTCs regarding connected ECUs that are output when the CAN No. 2 bus circuit main wire is malfunctioning, refer to the 4DTC COMBINATION TABLE (Can No. 2 Bus Circuit Main Wire Past Malfunction).

RESULT REFERENCE CHART

Inspection Result	Proceed to
ECU connected to CAN No. 1 bus circuit main wire has stored communication malfunction code (Can No. 1 bus circuit main wire past malfunction).	A
Except for hybrid vehicle control ECU, ECUs connected to CAN No. 2 bus circuit output all DTCs (all communication stop). Hybrid vehicle control ECU outputs network malfunction code (U1003) (CAN No. 2 bus circuit past malfunction)	B
Hybrid vehicle control ECU outputs malfunction code other than network malfunction code (U1003) (past malfunction of branch wire connected to CAN No. 2 bus circuit)	C

B: GO TO DTC U1003 FLOWCHART

C: GO TO PROBLEM SYMPTOMS TABLE

A: GO TO Next Step

CHECK DTC COMBINATION TABLE (CAN NO. 1 BUS CIRCUIT BRANCH WIRE OPEN PAST MALFUNCTION)
1. Based on the combination of stored CAN communication system DTCs, determine which ECUs and sensors have a communication stop malfunction (see DIAGNOSIS SYSTEM ).
PERFORM MALFUNCTION SIMULATION TEST (CAN NO. 1 BUS CIRCUIT MAIN WIRE PAST MALFUNCTION)*
1. Using the intelligent tester, clear all DTCs.
2. Perform a malfunction simulation test on all harnesses and connectors related to the CAN No. 1 bus circuit main wire.
3. Check the DTCs that were output as a result of the malfunction simulation test. Then determine the malfunctioning area.
ADJUST, REPAIR AND REPLACE
CONFIRMATION TEST
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