NETWORKING CAN COMMUNICATION SYSTEM Check CAN Bus Lines for Short Circuit
DESCRIPTION
There may be a short circuit between the V bus main lines and/or CAN branch lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ω.
| Symptom | Trouble Area |
|---|---|
| Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is below 54 Ω. | ·
Short in CAN main bus lines ·
Short in CAN branch lines ·
Combination meter assembly ·
Power steering ECU assembly ·
Main body ECU (multiplex network body ECU) ·
Airbag ECU assembly*1 ·
ECM ·
Skid control ECU (brake actuator assembly)*2 ·
Air conditioning amplifier assembly ·
No. 1 CAN junction connector ·
No. 2 CAN junction connector |
*1: w/ Airbag System
*2: for ABS
WIRING DIAGRAM
CAUTION / NOTICE / HINT
- NOTICE:
- ·
Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
·After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.
Click hereGeneral>INTRODUCTION>REPAIR INSTRUCTION>PRECAUTION
·Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.
Click herePower Source / Network>NETWORKING>CAN COMMUNICATION SYSTEM>HOW TO PROCEED WITH TROUBLESHOOTING
·After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
·DTC check procedure: Turn the ignition switch to ON and wait at least 20 seconds, and then drive the vehicle at a speed of 20 km/h (12 mph) or more for 300 seconds or more.
·After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed.
Click herePower Source / Network>NETWORKING>CAN COMMUNICATION SYSTEM>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.
·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.
PROCEDURE
Disconnect the cable from the negative (-) battery terminal.
| *a | Front view of wire harness connector
(to Combination Meter Assembly) |
Disconnect the E43 combination meter assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition E43-32 (CANH) - E43-31 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
- Result:
Result OK NG
OK
NG
Reconnect the E43 combination meter assembly connector.
| *A | for 2ZR-FE |
| *B | for 1ZR-FE |
| *C | for 2NZ-FE |
| *a | Front view of wire harness connector
(to ECM) |
Disconnect the A40 or A56 ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
for 2ZR-FE Tester Connection Condition Specified Condition A40-13 (CANH) - A40-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
for 1ZR-FE Tester Connection Condition Specified Condition A56-8 (CANH) - A56-9 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
for 2NZ-FE Tester Connection Condition Specified Condition A56-41 (CANH) - A56-49 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
- Result:
Result Proceed to OK (for 1ZR-FE) A OK (for 2ZR-FE) B OK (for 2NZ-FE) C NG D
A
B
C
D
Reconnect the A40 or A56 ECM connector.
| *a | Front view of wire harness connector
(to No. 1 CAN Junction Connector) |
| *b | to No. 2 CAN Junction Connector |
| *c | to Skid Control ECU (Brake Actuator Assembly)
(w/ ABS) |
| *d | to ECM |
Disconnect the A39 No. 1 CAN junction connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition Connected to A39-1 (CANH) - A39-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction connector A39-5 (CANH) - A39-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)* A39-6 (CANH) - A39-17 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
*: w/ ABS
- Result:
Result Proceed to OK A NG (No. 2 CAN junction connector main line) B NG (ECU or sensor branch line) C NG (ECM main line) D
A
B
C
D
Reconnect the A39 No. 1 CAN junction connector.
Disconnect the E55 No. 2 CAN junction connector.
| *a | Front view of wire harness connector
(to No. 2 CAN Junction Connector) |
*b | to Airbag ECU Assembly
(w/ Airbag System) |
| *c | to Air Conditioning Amplifier Assembly | *d | to Combination Meter Assembly |
| *e | to No. 1 CAN Junction Connector | *f | to Main Body ECU (Multiplex Network Body ECU) |
| *g | to Power Steering ECU Assembly | *h | to DLC3 |
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition Connected to E55-1 (CANH) - E55-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag ECU assembly* E55-2 (CANH) - E55-13 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly E55-4 (CANH) - E55-15 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly E55-5 (CANH) - E55-16 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 1 CAN junction connector E55-8 (CANH) - E55-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU) E55-9 (CANH) - E55-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly E55-11 (CANH) - E55-22 (CANL) Cable disconnected from negative (-) battery terminal 1 MΩ or higher DLC3
*: w/ Airbag System
- Result:
Result Proceed to OK A NG (No. 1 CAN junction connector main line) B NG (ECU or sensor branch line) C NG (DLC3 branch line) D NG (Combination meter assembly main line) E
A
B
C
D
E
Reconnect all wire harness connectors.
Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.
Click herePower Source / Network>NETWORKING>CAN COMMUNICATION SYSTEM>TERMINALS OF ECU
| *1 | DLC3 |
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition E13-6 (CANH) - E13-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
- HINT:
-
If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
- Result:
Result OK NG
OK
NG