CAN Communication (Diagnostics): Overview Lexus IS II facelift

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1. STEERING SYSTEM HANDLING PRECAUTIONS Care must be taken when replacing parts. Incorrect replacement could affect the performance of the steering system and result in hazardous driving.
2. SRS AIRBAG SYSTEM HANDLING PRECAUTIONS This vehicle is equipped with an Supplemental Restraint System (SRS) which includes components such as the driver airbag and front passenger airbag. Failure to carry out service operations in the correct sequence could cause unexpected SRS deployment during servicing and may lead to a serious accident. Before servicing (including removal or installation of parts, inspection or replacement), be sure to read the precautionary notice for the Supplemental Restraint System. Refer to «PRECAUTION»(ref-387382-S30774849502011022400000) .
3. BUS LINE REPAIR After repairing the bus line with solder, wrap the repaired part with electrical tape. NOTE: The CANL bus line and CANH bus line must be installed together all the times. When installing, make sure to twist them. CAN bus lines are likely to be influenced by electrical noise if they are not twisted. The difference in length between the CANL bus line and CANH bus line should be 100 mm (3.937 in.) or less. Leave approximately 80 mm (3.150 in.) loose in the twisted wires around the connector. Do not use bypass wiring between the connectors. NOTE: The ability of the twisted bus lines to resist interference will be lost if bypass wiring is used.
4. CONNECTOR HANDLING When checking resistance with a tester, insert the tester probes from the backside (harness side) of the connector. Use service wires to check the connector if it is impossible to check continuity from the rear of the connector.
5. PRECAUTION FOR DISCONNECTING THE BATTERY TERMINAL NOTE: When disconnecting the negative (-) battery terminal, initialize the following system(s) after the terminal is reconnected. System Name See Procedure Power Window Control System Refer to «CUSTOMIZE PARAMETERS»(ref-387197-S07771860982011022400000) Perform the RESET MEMORY (AT initialization) operation after replacing the automatic transmission assembly, engine assembly or ECM. HINT: RESET MEMORY cannot be completed by disconnecting the battery terminal.

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HINT

1. The skid control ECU detects and stores steering angle sensor and yaw rate sensor DTCs, and performs DTC communication by receiving information from the steering angle sensor and yaw rate sensor.

1. The ECM detects and stores distance control ECU DTCs, and performs DTC communication by receiving information from the distance control ECU.

SYSTEM DESCRIPTION

1. BRIEF DESCRIPTION The Control Area Network (CAN) is a serial data communication system for real time application. It is a vehicle multiplex communication system which has a high communication speed (500 kbps) and the ability to detect malfunctions. By pairing the CANH and CANL bus lines, the CAN performs communication based on differential voltage. Many ECUs (sensors) installed on the vehicle operate by sharing information and communicating with each other. The CAN has two resistors of 120 ohms which are necessary to communicate with the main bus line.
2. DEFINITION OF TERMS Main bus line The main bus line is a wire harness between the two terminating resistors on the bus (communication line). This is the main bus in the CAN communication system. Branch line The branch line is a wire harness which diverges from the main bus line to an ECU or sensor. Terminating resistors Two resistors of 120 ohms resistance are installed in parallel across the ends of the CAN main bus lines. They are called terminating resistors. These resistors allow the changes of the voltage differential between the CAN bus lines to be accurately judged. To allow proper function of CAN communication, it is necessary to have both terminating resistors installed. Since the two resistors are installed in parallel, a measurement of resistance between the two CAN bus lines should produce a reading of approximately 60 ohms.
3. ECUS OR SENSORS WHICH COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM Skid control ECU Yaw rate sensor Steering angle sensor Seat belt control ECU Distance control ECU Center airbag sensor ECM Gateway ECU Power steering ECU
4. DIAGNOSTIC CODE FOR CAN COMMUNICATION SYSTEM DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0121, U0122, U0123, U0124, U0126, U0129, U0146, U0151, U0235, U1101 and U1102.
5. TROUBLESHOOTING REMARKS DTCs for the CAN communication system can be checked using the Techstream via the CAN VIM. The DLC3 is connected to the CAN communication system, but no DTCs exist regarding problems in the DLC3 or the DLC3 branch lines. If there is trouble in the DLC3 or the DLC3 branch lines, ECUs on the CAN communication system output codes to the Techstream. Trouble in the CAN buses (communication lines) can be checked by measuring the resistance between terminals of the DLC3. However, an open circuit in a branch line other than the DLC3 branch lines cannot be checked from the DLC3. NOTE: Do not insert the tester probes directly into the DLC3. Be sure to use service wires.
6. HOW TO DISTINGUISH THE CAN J/C CONNECTOR In the CAN communication system, the shape of all connectors connected to the CAN J/C is the same. The connectors connected to the CAN J/C can be distinguished by the colors of the bus line and the connecting side of the junction connector. HINT: See "Terminals of ECU". Refer to «TERMINALS OF ECU»(ref-387391-S25427310852011022400000) for bus line color or the type of connecting surface.

DESCRIPTION

HINT

"ABS/VSC/TRAC" refers to the circuit that includes the skid control ECU.

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1. CHECK OPEN IN CAN BUS WIRE (SKID CONTROL ECU BRANCH LINE) Turn the engine switch off. Disconnect the skid control ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition A58-25 (CANH) - A58-14 (CANL) Engine switch on (IG) 54 to 69 ohms NG --> REPAIR OR REPLACE SKID CONTROL ECU BRANCH WIRE OR CONNECTOR (CAN-H, CAN-L) OK: Go to next step
2. CHECK WIRE HARNESS (IG1, GND1) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A58-1 (GND1) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A58-34 (IG1) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK DTC OUTPUT Connect the Techstream to the DLC3. Turn the engine switch to ON(IG). Enter the following menus: Chassis / ABS/VSC/TRAC / DTC. Check for DTC. OK C1241 is not output. NG --> See step 5 OK --> See step 4
4. REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU). Refer to «REMOVAL»(ref-387427-S37175345262011022400000)
5. GO TO DTC CHART. Refer to «DTC C1241: Low Power Supply Voltage Malfunction»(ref-387423-S32551897192011022400000)

HINT

"Cruise Control" refers to the circuit that includes the distance control ECU.

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1. CHECK OPEN IN CAN BUS WIRE (DISTANCE CONTROL ECU BRANCH LINE) Turn the engine switch off. Disconnect the distance control ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition J17-8 (CANH) - J17-9 (CANL) Engine switch off 54 to 69 ohms NG --> REPAIR OR REPLACE DISTANCE CONTROL ECU BRANCH WIRE OR CONNECTOR (CAN-H, CAN-L) OK: Go to next step
2. CHECK WIRE HARNESS (+B, GND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J17-12 (GND) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition J17-1 (+B) - Body ground Engine switch on (IG) 11 to 14 V OK --> REPLACE DISTANCE CONTROL ECU NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR

HINT

"Pre-Collision" refers to the circuit that includes the seat belt control ECU.

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1. CHECK OPEN IN CAN BUS WIRE (SEAT BELT CONTROL ECU BRANCH LINE) Turn the engine switch off. Disconnect the seat belt control ECU connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition Q59-1 (CANH) - Q58-2 (CANL) Engine switch off 54 to 69 ohms NG --> REPAIR OR REPLACE SEAT BELT CONTROL ECU BRANCH WIRE OR CONNECTOR (CAN-H, CAN-L) OK: Go to next step
2. CHECK WIRE HARNESS (IG1, PGND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Q58-8 (PGND) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition Q59-8 (IG1) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE SEAT BELT CONTROL ECU

HINT

"EPS" refers to the circuit that includes the power steering ECU.

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1. CHECK OPEN IN CAN BUS WIRE (POWER STEERING ECU BRANCH LINE) Turn the engine switch off. Disconnect the power steering ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition A31-2 (CANH) - A31-3 (CANL) Engine switch off 54 to 69 ohms NG --> REPAIR OR REPLACE POWER STEERING ECU BRANCH WIRE OR CONNECTOR (CANH, CANL) OK: Go to next step
2. CHECK WIRE HARNESS (IG, PGND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A31-5 (PGND) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A31-9 (IG) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE POWER STEERING ECU

HINT

"Gateway" refers to the circuit that includes the gateway ECU.

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1. CHECK WIRE HARNESS (BATT, ACC, IG, GND) Turn the engine switch off. Disconnect the gateway ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J76-24 (GND) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition J76-10 (BATT) - Body ground Always 11 to 14 V J76-2 (ACC) - Body ground Engine switch on (IG) 11 to 14 V J76-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE GATEWAY ECU

HINT

"Steering Angle Sensor" refers to the circuit that includes the steering angle sensor.

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1. CHECK OPEN IN CAN BUS WIRE (STEERING ANGLE SENSOR BRANCH LINE) Turn the engine switch off. Disconnect the steering angle sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition J23-10 (CANH) - J23-9 (CANL) Engine switch off 54 to 69 ohms NG --> REPAIR OR REPLACE STEERING ANGLE SENSOR BRANCH WIRE OR CONNECTOR (CANH, CANL) OK: Go to next step
2. CHECK WIRE HARNESS (IG, ESS) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J23-2 (ESS) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition J23-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE STEERING ANGLE SENSOR

HINT

"Yaw Rate / Deceleration Sensor" refers to the circuit that includes the yaw rate sensor.

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1. CHECK OPEN IN CAN BUS WIRE (YAW RATE SENSOR BRANCH LINE) Turn the engine switch off. Disconnect the yaw rate sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition J41-3 (CANH) - J41-2 (CANL) Engine switch off 54 to 69 ohms NG --> REPAIR OR REPLACE YAW RATE SENSOR BRANCH WIRE OR CONNECTOR (CANH, CANL) OK: Go to next step
2. CHECK WIRE HARNESS (IG, GND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J41-1 (GND) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition J41-5 (IG) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE YAW RATE AND ACCELERATION SENSOR

HINT

"Engine" and "ECT" refer to the circuit that includes the ECM.

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HINT

"SRS Airbag" refers to the circuit that includes the center airbag sensor.

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1. CHECK OPEN IN CAN BUS WIRE (CENTER AIRBAG SENSOR BRANCH LINE) Turn the engine switch off. Disconnect the center airbag sensor connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition J47-13 (CANH) - J47-22 (CANL) Engine switch off 54 to 69 ohms NG --> REPAIR OR REPLACE CENTER AIRBAG SENSOR BRANCH WIRE OR CONNECTOR (CANH, CANL) OK: Go to next step
2. CHECK WIRE HARNESS (IG2, E1, E2) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J47-25 (E1) - Body ground Always Below 1 ohms J47-26 (E2) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition J47-21 (IG2) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE CENTER AIRBAG SENSOR ASSEMBLY

HINT

"Four Wheel Drive Control" refers to the circuit that includes the 4WD control ECU.

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1. CHECK OPEN IN CAN BUS WIRE (4WD CONTROL ECU BRANCH LINE) Turn the engine switch off. Disconnect the 4WD control ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition A32-14 (CANH) - A32-16 (CANL) Engine switch off 54 to 69 ohms NG --> REPAIR OR REPLACE 4WD CONTROL ECU BRANCH WIRE OR CONNECTOR (CANH, CANL) OK: Go to next step
2. CHECK WIRE HARNESS (IG1, GND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A32-23 (GND) - Body ground Always Below 1 ohms Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A32-11 (IG1) - Body ground Engine switch on (IG) 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE 4WD CONTROL ECU

There may be an open circuit in the CAN main bus line and/or the DLC3 branch line when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is 70 ohms or more.

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1. CHECK DLC3 Turn the engine switch off. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Value Result J21-6 (CANH) -J21-14 (CANL) Engine switch off 108 to 132 ohms A J21-6 (CANH) - J21-14 (CANL) Engine switch off 132 ohms or higher B NOTE: When the measured value is 133 ohms or more and a CAN communication system DTC is output, there may be a fault besides disconnection of the DLC3 branch line. For that reason, troubleshooting should be performed again from "HOW TO PROCEED WITH TROUBLESHOOTING". Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-387391-S01390035312011022400000) after repairing the trouble area. B --> REPAIR OR REPLACE DLC3 BRANCH LINE OR CONNECTOR (CANH, CANL) A: Go to next step
2. CHECK FOR OPEN IN CAN BUS MAIN WIRE (CAN BUS CHECK) Perform "CAN Bus Check" using the Techstream. Refer to «DIAGNOSIS SYSTEM»(ref-387391-S05169532582011022400000) . Result Specified Condition Proceed to "Engine" and "ECT" only are not displayed A "Body/Gateway" only is not displayed B Others C C --> See step 7 B --> See step 4 A: Go to next step
3. CHECK FOR OPEN IN CAN BUS MAIN WIRE (ECM - CAN LH J/C) Turn the engine switch off. Disconnect the ECM connector (A5). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A5-25 (CANH) - A5-24 (CANL) Engine switch off 108 to 132 ohms NG --> REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (ECM - CAN LH J/C) OK --> REPLACE ECM
4. CHECK FOR OPEN IN CAN BUS MAIN WIRE (GATEWAY ECU - CAN LH J/C) Turn the engine switch off. Disconnect the gateway ECU connector (J76). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J76-17 (CA1H) - J76-18 (CA1L) Engine switch off 108 to 132 ohms OK --> REPLACE GATEWAY ECU NG: Go to next step
5. RECONNECT CONNECTOR Reconnect the gateway ECU connector (J76). NEXT: Go to next step
6. CHECK FOR OPEN IN CAN BUS MAIN WIRE (CAN RH J/C - GATEWAY ECU) Disconnect the CAN main bus line connector (J84) from the CAN RH J/C B side (w/o earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J84-1 (CANH) - J84-2 (CANL) Engine switch off 108 to 132 ohms NG --> REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN RH J/C - GATEWAY ECU) OK --> REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN LH J/C - CAN RH J/C)
7. CHECK FOR OPEN IN CAN BUS MAIN WIRE (ECM - CAN LH J/C) Turn the engine switch off. Disconnect the ECM connector (A5). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A5-25 (CANH) - A5-24 (CANL) Engine switch off 108 to 132 ohms OK --> REPLACE ECM NG: Go to next step
8. RECONNECT CONNECTOR Reconnect the ECM connector (A5). NEXT: Go to next step
9. CHECK FOR OPEN IN CAN BUS MAIN WIRE (GATEWAY ECU - CAN LH J/C) Disconnect the gateway ECU connector (J76). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J76-17 (CA1H) - J76-18 (CA1L) Engine switch off 108 to 132 ohms OK --> REPLACE GATEWAY ECU NG: Go to next step
10. RECONNECT CONNECTOR Reconnect the gateway ECU connector (J76). NEXT: Go to next step
11. CHECK FOR OPEN IN CAN BUS MAIN WIRE (CAN RH J/C - GATEWAY ECU) Disconnect the CAN main bus line connector (J84) from the CAN RH J/C B side (w/o earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Value J84-1 (CANH) - J84-2 (CANL) Engine switch off 108 to 132 ohms NG --> REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN RH J/C - GATEWAY ECU) OK: Go to next step
12. RECONNECT CONNECTOR Reconnect the CAN main bus line connector (J84) to the CAN RH J/C B side (without earth terminal). NEXT: Go to next step
13. CHECK FOR OPEN IN CAN BUS MAIN WIRE (ECM - CAN LH J/C) Disconnect the CAN main bus line connector (J2) from the CAN LH J/C A side (w/ earth terminal). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J2-1 (CANH) - J2-2 (CANL) Engine switch off 108 to 132 ohms NG --> REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (ECM - CAN LH J/C) OK --> REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN LH J/C - CAN RH J/C)

The CAN bus lines are considered to be shorted when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 ohms.

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1. CHECK FOR SHORT IN CAN BUS WIRES (DLC3 BRANCH LINE) Turn the engine switch off. Disconnect the DLC3 branch line connector (J8) from the CAN LH J/C B side (w/o earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 1 Mohms or higher NG --> REPAIR OR REPLACE DLC3 BRANCH WIRE OR CONNECTOR OK: Go to next step
2. RECONNECT CONNECTOR Reconnect the DLC3 branch line connector (J8) to the CAN LH J/C B side (w/o earth terminal). NEXT: Go to next step
3. CHECK FOR SHORT IN CAN BUS WIRES (BRANCH LINE) Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3. While observing the resistance value shown on the tester, disconnect connectors J1, J3, J4, J5, J6, J9, J82 and J86 from the CAN LH J/C or CAN RH J/C one by one until the resistance becomes normal (between 54 and 69 ohms). HINT: Disconnect the branch line connectors other than those of the DLC3. WIRING COLOR: CAN LH J/C A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side) Steering angle sensor J1 P W ECM J2 B W Seat belt control ECU (w/ Pre-collision system) J3 V W Center airbag sensor J4 R W WIRING COLOR: CAN LH J/C B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side) Yaw rate sensor J5 P W Skid control ECU J6 R W CAN main bus line (bus line connecting CAN LH J/C and CAN RH J/C) J7 B W DLC3 J8 G W Distance control ECU (w/ Dynamic radar cruise control system) J9 GR W WIRING COLOR: CAN RH J/C A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side) CAN main bus line (bus line connecting CAN RH J/C and CAN LH J/C) J81 B W Power steering ECU J82 P W WIRING COLOR: CAN RH J/C B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side) Gateway ECU J84 B W 4WD control ECU (for 4WD) J86 V W NOTE: Do not reconnect the disconnected connectors until this inspection is complete because there may be a short in 2 or more branch lines. Result Symptom Proceed to The resistance is still below 54 ohms when all the specified connectors are disconnected. (There are no shorts in the branch lines.) A The resistance becomes normal (between 54 and 69 ohms) when a connector is disconnected. (There is a short in one or more of the branch lines.) B When there is a short in one or more of the branch lines: Reconnect all of the connectors to the CAN J/C, except for the one that was disconnected last (the short-circuited bus line). Check that the resistance shown on the tester is normal (between 54 and 69 ohms) to confirm that there is a short in the one branch line only. HINT: The connectors connected to the CAN J/C can be distinguished according to the color of the communication bus lines and the shape of the connectors. Reconnecting the connectors to non-specified positions on the CAN J/C does not affect system operation. However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier. B --> See step 9 A: Go to next step
4. CHECK FOR SHORT IN CAN BUS WIRES (GATEWAY ECU MAIN BUS LINE) Disconnect the gateway ECU main bus line connector (J84) from the CAN RH J/C B side (w/o earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 108 to 132 ohms Result Symptom Proceed to The resistance is still below 54 ohms when the gateway ECU connector is disconnected. (There are no shorts in the gateway ECU main bus lines.) A The resistance falls within the specified range (between 108 and 132 ohms) (either of the terminating resistances is normal) when the gateway ECU connector is disconnected. (There is a short in the gateway ECU main bus lines.) B B --> See step 11 A: Go to next step
5. CHECK FOR SHORT IN CAN BUS WIRES (ECM MAIN BUS LINE) Disconnect the ECM main bus line connector (J2) from the CAN LH J/C A side (w/ earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 1 Mohms or higher HINT: Measure the resistance with the gateway ECU main bus line connector (J84) disconnected. Result Symptom Proceed to The resistance is still below 1 Mohms when the ECM connector is disconnected. (There are no shorts in the ECM main bus lines.) A The resistance becomes 1 Mohms or more when the ECM connector is disconnected. (There is a short in the ECM main bus lines.) B B --> See step 13 A: Go to next step
6. CHECK CAN LH J/C Disconnect the CAN main bus line connector (J7) from the CAN LH J/C B side (w/o earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 1 Mohms or higher NG --> REPLACE CAN LH J/C OK: Go to next step
7. RECONNECT CONNECTOR Reconnect the CAN main bus line connector (J7) to the CAN LH J/C B side (w/o earth terminal). NEXT: Go to next step
8. CHECK CAN RH J/C Disconnect the CAN main bus line connector (J81) from the CAN RH J/C A side (w/ earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 1 Mohms or higher OK --> REPLACE CAN RH J/C NG --> REPAIR OR REPLACE CAN BUS MAIN WIRE (CAN LH J/C - CAN RH J/C)
9. RECONNECT CONNECTOR Reconnect the connector for the short-circuited branch line to the CAN J/C (the connector that caused the bus line resistance to become normal (between 54 and 69 ohms) when it was disconnected). NEXT: Go to next step
10. CHECK FOR SHORT IN CAN BUS WIRES Disconnect the connector that includes terminals CANH and CANL from the ECU (or sensor) to which the short-circuited branch line is connected.. Refer to «TERMINALS OF ECU»(ref-387391-S25427310852011022400000) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 1 Mohms or higher HINT: If the resistance becomes normal (between 54 and 69 ohms) when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor). NG --> REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH WIRE OR CONNECTOR OK --> REPLACE CORRESPONDING ECU OR SENSOR
11. RECONNECT CONNECTOR Reconnect the gateway ECU main bus line connector (J84) to the CAN RH J/C B side (w/o earth terminal). NEXT: Go to next step
12. CHECK FOR SHORT IN CAN BUS WIRES (GATEWAY ECU) Disconnect the gateway ECU connector (J76). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 108 to 132 ohms HINT: If the resistance becomes normal (between 108 to 132 ohms) when the connector is disconnected, there may be a short in the gateway ECU. NG --> REPAIR OR REPLACE CAN BUS MAIN WIRE (GATEWAY ECU MAIN BUS LINE) OK --> REPLACE GATEWAY ECU
13. RECONNECT CONNECTOR Reconnect the ECM main bus line connector (J2) to the CAN LH J/C A side (w/ earth terminal). NEXT: Go to next step
14. CHECK FOR SHORT IN CAN BUS WIRES (ECM) Disconnect the ECM connector (A5). Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-14 (CANL) Engine switch off 1 Mohms or higher HINT: Measure the resistance with the gateway ECU main bus line connector (J84) disconnected. If the resistance changes to 1 Mohms or more when the connector is disconnected, there may be a short in the ECM. NG --> REPAIR OR REPLACE CAN BUS MAIN WIRE (ECM MAIN BUS LINE) OK --> REPLACE ECM

A short to B+ is suspected in the CAN bus line when the resistance between terminals 6 (CANH) and 16 (BAT), or terminals 14 (CANL) and 16 (BAT) of the DLC3 is below 6 kohms.

Scheme 83

1. CHECK FOR SHORT TO B+ IN CAN BUS WIRE Disconnect the cable from negative (-) battery terminal. Disconnect the DLC3 branch line connector (J8) from the CAN LH J/C B side (w/o earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kohms or higher J21-14 (CANL) - J21-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kohms or higher NG --> REPAIR OR REPLACE DLC3 BRANCH WIRE OR CONNECTOR OK: Go to next step
2. RECONNECT CONNECTOR Reconnect the DLC3 branch line connector (J8) to the CAN LH J/C B side (w/o earth terminal). NEXT: Go to next step
3. CHECK FOR SHORT TO B+ IN CAN BUS WIRE Disconnect connectors from the CAN LH J/C or CAN RH J/C one at a time. HINT: Disconnect the ECU and sensor connectors other than the DLC3 branch lines and CAN main bus lines between the CAN LH J/C and CAN RH J/C. Using an ohmmeter, measure the resistance between terminals 6 (CANH) and 16 (BAT), and between terminals 14 (CANL) and 16 (BAT) of the DLC3 each time a connector is disconnected. WIRING COLOR: CAN LH J/C A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side) Steering angle sensor J1 P W ECM J2 B W Seat belt control ECU (w/ Pre-collision system) J3 V W Center airbag sensor J4 R W WIRING COLOR: CAN LH J/C B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side) Yaw rate sensor J5 P W Skid control ECU J6 R W CAN main bus line (bus line connecting CAN LH J/C and CAN RH J/C) J7 B W DLC3 J8 G W Distance control ECU (w/ Dynamic radar cruise control system) J9 GR W WIRING COLOR: CAN RH J/C A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side) CAN main bus line (bus line connecting CAN RH J/C and CAN LH J/C) J81 B W Power steering ECU J82 P W WIRING COLOR: CAN RH J/C B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side) Gateway ECU J84 B W 4WD control ECU (for 4WD) J86 V W NOTE: Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to B+ in 2 or more CAN bus lines. Result Symptom Proceed to The resistance between terminals 6 (CANH) and 16 (BAT), or the resistance between 14 (CANL) and 16 (BAT) is still below 6 kohms when all the specified connectors are disconnected from the CAN J/C. (There is a short to B+ in the CAN main bus lines between the CAN LH J/C and CAN RH J/C.) A The resistance between terminals 6 (CANH) and 16 (BAT), or the resistance between 14 (CANL) and 16 (BAT) becomes normal (6 kohms or more) when a connector is disconnected from the CAN J/C. (There is a short to B+ in one of the areas that relate to one or more of the disconnected bus lines.) B When there is a short to B+ in one or more of the bus lines that connect to an ECU (or sensor): Reconnect all of the connectors to the CAN J/C, except for the one that was disconnected last (the bus line that is shorted to B+). Check that the resistance shown on the tester is normal (6 kohms or more) to confirm that there is a short to B+ in the one bus line only. HINT: The connectors connected to the CAN J/C can be distinguished according to the color of the communication bus lines and the shape of the connectors. Reconnecting the connectors to non-specified positions on the CAN J/C does not affect system operation. However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier. A --> REPAIR OR REPLACE CAN BUS MAIN WIRE (CAN LH J/C - CAN RH J/C) B: Go to next step
4. RECONNECT CONNECTOR Reconnect the connector of the bus line that is shorted to B+ to the CAN J/C (the connector that caused the bus line resistance to change to 6 kohms or more when it was disconnected). NEXT: Go to next step
5. CHECK FOR SHORT TO B+ IN CAN BUS WIRE Disconnect the connector that includes terminals CANH and CANL from the ECU (or sensor) to which the bus line shorted to B+ is connected. Refer to «TERMINALS OF ECU»(ref-387391-S25427310852011022400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J21-6 (CANH) - J21-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kohms or higher J21-14 (CANL) - J21-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kohms or higher HINT: If the resistance changes to 6 kohms or higher when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor). NG --> REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BUS LINE OR CONNECTOR OK --> REPLACE CORRESPONDING ECU OR SENSOR

A short to GND is suspected in the CAN bus line when the resistance between terminals 4 (CG) and 6 (CANH), or terminals 4 (CG) and 14 (CANL) of the DLC3 is below 200 ohms.

Scheme 84

1. CHECK FOR SHORT TO GND IN CAN BUS WIRE Turn the engine switch off. Disconnect the DLC3 branch line connector (J8) from the CAN LH J/C B side (w/o earth terminal). NOTE: Before disconnecting the connector, make a note of where it is connected. Reconnect the connector to its original position. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition J21-6 (CANH) - J21-4 (CG) Engine switch off 200 ohms or higher J21-14 (CANL) - J21-4 (CG) Engine switch off 200 ohms or higher NG --> REPAIR OR REPLACE DLC3 BRANCH WIRE OR CONNECTOR OK: Go to next step
2. RECONNECT CONNECTOR Reconnect the DLC3 branch line connector (J8) to the CAN LH J/C B side (w/o earth terminal). NEXT: Go to next step
3. CHECK FOR SHORT TO GND IN CAN BUS WIRE Disconnect connectors from the CAN LH J/C or CAN RH J/C one at a time. HINT: Disconnect the ECU and sensor connectors other than the DLC3 branch lines and CAN main bus lines between the CAN LH J/C and CAN RH J/C. Using an ohmmeter, measure the resistance between terminals 6 (CANH) and 4 (CG), and between terminals 14 (CANL) and 4 (CG) of the DLC3 each time a connector is disconnected. WIRING COLOR: CAN LH J/C A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side) Steering angle sensor J1 P W ECM J2 B W Seat belt control ECU (w/ Pre-collision system) J3 V W Center airbag sensor J4 R W WIRING COLOR: CAN LH J/C B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side) Yaw rate sensor J5 P W Skid control ECU J6 R W CAN main bus line (bus line connecting CAN LH J/C and CAN RH J/C) J7 B W DLC3 J8 G W Distance control ECU (w/ Dynamic radar cruise control system) J9 GR W WIRING COLOR: CAN RH J/C A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side) CAN main bus line (bus line connecting CAN RH J/C and CAN LH J/C) J81 B W Power steering ECU J82 P W WIRING COLOR: CAN RH J/C B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side) Gateway ECU J84 B W 4WD Control ECU (for 4WD) J86 V W NOTE: Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to GND in 2 or more CAN bus lines. Result Symptom Proceed to The resistance between terminals 6 (CANH) and 4 (CG), or the resistance between 14 (CANL) and 4 (CG) is still below 200 ohms when all the specified connectors are disconnected from the CAN J/C. (There is a short to GND in the CAN main bus lines between the CAN LH J/C and CAN RH J/C.) A The resistance between terminals 6 (CANH) and 4 (CG), or the resistance between 14 (CANL) and 4 (CG) becomes normal (200 ohms or more) when a connector is disconnected from the CAN J/C. (There is a short to GND in one of the areas that relate to the disconnected bus lines.) B When there is a short to GND in one or more of the bus lines that connect to an ECU (or sensor): Reconnect all of the connectors to the CAN J/C, except for the one that was disconnected last (the bus line that is shorted to GND). Check that the resistance shown on the tester is normal (200 ohms or more) to confirm that there is a short to GND in the one branch line only. HINT: The connectors connected to the CAN J/C can be distinguished according to the color of the communication bus lines and the shape of the connectors. Reconnecting the connectors to non-specified positions on the CAN J/C does not affect system operation. However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier. A --> REPAIR OR REPLACE CAN BUS MAIN WIRE (CAN LH J/C - CAN RH J/C) B: Go to next step
4. RECONNECT CONNECTOR Reconnect the connector of the bus line that is shorted to GND to the CAN J/C (the connector that caused the bus line resistance to change to 200 ohms or more when it was disconnected). NEXT: Go to next step
5. CHECK FOR SHORT TO GND IN CAN BUS WIRE Disconnect the connector that includes terminals CANH and CANL from the ECU (or sensor) to which the bus line shorted to GND is connected. Refer to «TERMINALS OF ECU»(ref-387391-S25427310852011022400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition J21-6 (CANH) - J21-4 (CG) Engine switch off 200 ohms or higher J21-14 (CANL) - J21-4 (CG) Engine switch off 200 ohms or higher HINT: If the resistance changes to 200 ohms or higher when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor). NG --> REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BUS LINE OR CONNECTOR OK --> REPLACE CORRESPONDING ECU OR SENSOR

If some ECUs and sensors are not displayed on the "CAN Bus Check" screen of the Techstream and some ECUs and sensors repeatedly appear and disappear from the screen when the CAN main bus lines are normal (there is no open, short, short to B+, or short to GND in the main bus lines), there may be an open circuit in either of the CAN branch lines.

HINT

If some ECUs and sensors repeatedly appear and disappear from the "CAN Bus Check" screen, communication between the normal ECUs (sensors) and Techstream may be affected by the incomplete signals that are output from the ECU that has an open circuit in either of its CAN branch lines. In this case, the CAN branch lines for the ECUs and sensors that repeatedly appear and disappear from the screen are normal and the ECU that is not displayed on the screen may be the main cause of the problem (this ECU may have an open circuit in either of its CAN branch lines).