Toyota Camry (XV70): Check Bus 4 Line for Short to +B
DESCRIPTION
There may be a short circuit between one of the CAN bus lines and +B when there is no resistance between terminal 22 (CA2H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 7 (CA2L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.
|
Symptom | Trouble Area |
|---|---|
|
There is no resistance between terminal 22 (CA2H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 7 (CA2L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3. |
|
WIRING DIAGRAM
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CAUTION / NOTICE / HINT
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
NOTICE:
- 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.
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- 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.
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- 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 for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes 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 as normal.
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HINT:
- Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
- When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.
PROCEDURE
|
1. | CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 3 JUNCTION CONNECTOR) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the R99 No. 3 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
|
*1 | DLC3 |
- | - |
|
*a | Front view of wire harness connector (to No. 3 Junction Connector) |
*b | to Tire Pressure Warning ECU and Receiver (for Tire Pressure Warning System with Tire Inflation Pressure Display Function) |
|
*c | to Occupant Detection ECU |
*d | to Central Gateway ECU (Network Gateway ECU) |
|
*e | to No. 2 CAN Junction Connector |
- | - |
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition | Connected to |
|---|---|---|---|
|
R99-8 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
Tire pressure warning ECU and receiver* |
|
R99-19 (CANL) - K138-16 (BAT) | |||
|
R99-9 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
Occupant detection ECU |
|
R99-20 (CANL) - K138-16 (BAT) | |||
|
R99-10 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
Central gateway ECU (network gateway ECU) |
|
R99-21 (CANL) - K138-16 (BAT) | |||
|
R99-11 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
No. 2 CAN junction connector |
|
R99-22 (CANL) - K138-16 (BAT) |
- *: for Tire Pressure Warning System with Tire Inflation Pressure Display Function
|
Result | Proceed to |
|---|---|
|
OK | A |
|
NG (Line to central gateway ECU (network gateway ECU)) |
B |
| NG (Line to No. 2 CAN junction connector) |
C |
| NG (Line to ECU or sensor) |
D |
| A |
.gif) | REPLACE NO. 3 JUNCTION CONNECTOR |
| C |
| GO TO STEP 3 |
| D |
| GO TO STEP 7 |
|
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| 2. |
CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 3 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
(a) Disconnect the K76 central gateway ECU (network gateway ECU) connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*1 | DLC3 |
- | - |
|
*a | Front view of wire harness connector (to No. 3 Junction Connector) |
*b | to Central Gateway ECU (Network Gateway ECU) |
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
R99-10 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
|
R99-21 (CANL) - K138-16 (BAT) |
| OK | | REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 3 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
| 3. |
CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR) |
(a) Disconnect the A67 No. 2 CAN junction connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*1 | DLC3 |
- | - |
|
*a | Front view of wire harness connector (to No. 2 CAN Junction Connector) |
*b | to Brake Actuator Assembly |
|
*c | to No. 3 Junction Connector |
*d | to Rack and Pinion Power Steering Gear Assembly |
|
*e | to No. 4 CAN Junction Connector |
*f | to 4WD ECU Assembly (for AWD) |
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition | Connected to |
|---|---|---|---|
|
A67-1 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
Brake actuator assembly |
|
A67-12 (CANL) - K138-16 (BAT) | |||
|
A67-2 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
No. 3 junction connector |
|
A67-13 (CANL) - K138-16 (BAT) | |||
|
A67-4 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
Rack and pinion power steering gear assembly |
|
A67-15 (CANL) - K138-16 (BAT) | |||
|
A67-5 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
No. 4 CAN junction connector |
|
A67-16 (CANL) - K138-16 (BAT) | |||
|
A67-6 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
4WD ECU Assembly* |
|
A67-17 (CANL) - K138-16 (BAT) |
- *: for AWD
|
Result | Proceed to |
|---|---|
|
OK | A |
|
NG (Line to No. 3 junction connector) |
B |
| NG (Line to No. 4 CAN junction connector) |
C |
| NG (Line to ECU or sensor) |
D |
| A |
| REPLACE NO. 2 CAN JUNCTION CONNECTOR |
| B |
| REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR) |
| D |
| GO TO STEP 7 |
|
| 4. |
CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR) |
(a) Disconnect the K128 No. 4 CAN junction connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*1 | DLC3 |
- | - |
|
*a | Front view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | to Airbag Sensor Assembly |
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition | Connected to |
|---|---|---|---|
|
K128-6 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
Airbag sensor assembly |
|
K128-17 (CANL) - K138-16 (BAT) |
| NG | | GO TO STEP 6 |
|
| 5. |
CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR) |
(a) Disconnect the K127 No. 4 CAN junction connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*1 | DLC3 |
- | - |
|
*a | Front view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | to No. 2 CAN Junction Connector |
|
*c | to Steering Sensor |
- | - |
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition | Connected to |
|---|---|---|---|
|
K127-6 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
No. 2 CAN junction connector |
|
K127-17 (CANL) - K138-16 (BAT) | |||
|
K127-7 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
Steering sensor |
|
K127-18 (CANL) - K138-16 (BAT) |
|
Result | Proceed to |
|---|---|
|
OK | A |
|
NG (Line to No. 2 CAN junction connector) |
B |
| NG (Line to ECU or sensor) |
C |
| A |
| REPLACE NO. 4 CAN JUNCTION CONNECTOR |
| B |
| REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR) |
| C |
| GO TO STEP 7 |
| 6. |
CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR - AIRBAG SENSOR ASSEMBLY) |
(a) Disconnect the K73 airbag sensor assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*1 | DLC3 |
- | - |
|
*a | Front view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | to Airbag Sensor Assembly |
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
K128-6 (CANH) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
|
K128-17 (CANL) - K138-16 (BAT) |
| OK | | REPLACE AIRBAG SENSOR ASSEMBLY |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - AIRBAG SENSOR ASSEMBLY) |
| 7. |
CHECK FOR SHORT TO +B IN CAN BUS LINE (ECU OR SENSOR) |
(a) Reconnect all wire harness connectors.
(b) Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to +B is connected.
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(c) Measure the resistance according to the value(s) in the table below.
|
*1 | DLC3 |
- | - |
|
*a | Component with harness connected (Central Gateway ECU (Network Gateway ECU)) |
- | - |
Standard Resistance:
|
Tester Connection | Condition |
Specified Condition |
|---|---|---|
|
K76-22 (CA2H) - K138-16 (BAT) |
Cable disconnected from negative (-) battery terminal |
6 kΩ or higher |
|
K76-7 (CA2L) - K138-16 (BAT) |
HINT:
- If the resistance changes to 6 kΩ or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
- If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short to +B in the wire harness and repair or replace the wire harness or connector if necessary.
| OK | | REPLACE ECU OR SENSOR |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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