Last Modified: 11-29-2007 1.6 J
Service Category: Power Source/Network Section: Networking
Model Year: 2008 Model: Sequoia Doc ID: RM000002VTE002X
Title: NETWORKING: CAN COMMUNICATION SYSTEM: DESCRIPTION (2008 Sequoia)

Short to GND in CAN Bus Line

DESCRIPTION

There may be a short circuit between the CAN bus line and GND when there is resistance between terminals 6 (CANH) and 4 (CG) or terminals 14 (CANL) and 4 (CG) of the DLC3.

Symptom

Trouble Area

There is resistance between terminals 6 (CANH) and 16 (BAT) or terminals 14 (CANL) and 16 (BAT) of DLC3.

  • Short to +B
  • Combination meter ECU
  • Main body ECU
  • Skid control ECU
  • Steering angle sensor
  • Center airbag sensor
  • Bus buffer ECU*1
  • Air conditioning amplifier
  • ECM
  • Power steering ECU
  • 4WD control ECU*2
  • Suspension control ECU*3
  • Distance control ECU*4
  • No. 1 junction connector
  • No. 2 junction connector
  • No. 4 junction connector*3

HINT:

  • *1: w/ Bus Buffer ECU
  • *2: w/ 4WD
  • *3: w/ Air suspension system
  • *4: w/ Dynamic laser cruise control

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT:

Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE

1.

DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

(a) Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NEXT

2.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (DLC3 BRANCH WIRE)


(a) Disconnect the H93 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H19-6 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H19-14 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

3.

CONNECT CONNECTOR

(a) Reconnect the H93 No. 1 junction connector.

NEXT

4.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR SIDE)


(a) Disconnect the H100 No. 2 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H19-6 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H19-14 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

5.

CONNECT CONNECTOR

(a) Reconnect the H100 No. 2 junction connector.

NEXT

6.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - AIR CONDITIONING AMPLIFIER)


(a) Disconnect the H92 No. 2 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H92-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H92-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

7.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - BUS BUFFER ECU)

NOTICE:

For vehicles without bus buffer ECU, go to "Check for Short to GND in CAN Bus Wire (No. 2 Junction Connector - 4WD Control ECU)".


(a) Disconnect the H105 No. 2 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H105-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H105-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

8.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - 4WD CONTROL ECU)

NOTICE:

For vehicles without 4WD, go to "Check for Short to GND in CAN Bus Wire (No. 2 Junction Connector - ECM)".


(a) Disconnect the H92 No. 2 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H95-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H95-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

9.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 2 JUNCTION CONNECTOR - ECM)


(a) Disconnect the H99 No. 2 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H99-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H99-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

11.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER)


(a) Disconnect the H24 air conditioning amplifier connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H92-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H92-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

13.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (BUS BUFFER ECU)


(a) Disconnect the H66 bus buffer ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H105-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H105-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

15.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (4WD CONTROL ECU)


(a) Disconnect the A28 4WD control ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H95-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H95-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

17.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECM)


(a) Disconnect the A27 ECM connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H99-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H99-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

Result

Result

Proceed to

NG

A

OK (for 2UZ-FE)

B

OK (for 3UR-FE)

C

A

19.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR)


(a) Disconnect the H101 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H101-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H101-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

20.

CONNECT CONNECTOR

(a) Reconnect the H101 No. 1 junction connector.

(b) Reconnect the H100 No. 2 junction connector.

NEXT

21.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 4 JUNCTION CONNECTOR SIDE)

NOTICE:

For vehicles without air suspension system, go to "Check for Short to GND in CAN Bus Wire (No. 1 Junction Connector - Combination Meter ECU)".


(a) Disconnect the O41 No. 4 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H19-6 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H19-14 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

22.

CONNECT CONNECTOR

(a) Reconnect the O41 No. 4 junction connector.

NEXT

23.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 4 JUNCTION CONNECTOR - SUSPENSION CONTROL ECU)


(a) Disconnect the O42 No. 4 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

O42-6 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

O42-12 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

24.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 4 JUNCTION CONNECTOR - COMBINATION METER ECU)


(a) Disconnect the O41 No. 4 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

O41-2 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

O41-8 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

26.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - NO. 4 JUNCTION CONNECTOR)


(a) Disconnect the H91 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H91-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H91-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

27.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - COMBINATION METER ECU)

NOTICE:

For vehicles without air suspension system, go to "Check for Short to GND in CAN Bus Wire (No. 1 Junction Connector - Combination Meter ECU)".


(a) Disconnect the H91 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H91-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H91-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

28.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - POWER STEERING ECU)


(a) Disconnect the H106 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H106-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H106-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

29.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - DISTANCE CONTROL ECU)

NOTICE:

For vehicles with air suspension system, go to "Check for Short to GND in CAN Bus Wire (No. 1 Junction Connector - Main Body ECU)".


(a) Disconnect the A60 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

A60-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

A60-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

30.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - MAIN BODY ECU)


(a) Disconnect the H103 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H103-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H103-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

31.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - SKID CONTROL ECU)


(a) Disconnect the A59 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

A59-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

A59-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

32.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - STEERING ANGLE SENSOR)


(a) Disconnect the H94 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H94-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H94-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

33.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 JUNCTION CONNECTOR - CENTER AIRBAG SENSOR)


(a) Disconnect the H90 No. 1 junction connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H90-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H90-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

35.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (SUSPENSION CONTROL ECU)


(a) w/ AVS

(1) Disconnect the O18 suspension control ECU connector.

(2) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

O42-6 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

O42-12 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

(b) w/o AVS

(1) Disconnect the O19 suspension control ECU connector.

(2) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

O42-6 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

O42-12 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

37.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (COMBINATION METER ECU)


(a) Disconnect the H37 combination meter ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H37-33 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H37-34 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

39.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (POWER STEERING ECU)


(a) Disconnect the H38 power steering ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H106-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H106-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

41.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (DISTANCE CONTROL ECU)


(a) Disconnect the A43 distance control ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

A60-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

A60-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

43.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (MAIN BODY ECU)


(a) Disconnect the H2 main body ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H103-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H103-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

45.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (SKID CONTROL ECU)


(a) Disconnect the A19 skid control ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

A59-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

A59-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

47.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (STEERING ANGLE SENSOR)


(a) Disconnect the H6 steering angle sensor connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H94-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H94-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK

49.

CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTER AIRBAG SENSOR)


(a) Disconnect the H56 center airbag sensor connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

H90-1 (CANH) - H19-4 (CG)

Ignition switch off

200 Ω or higher

H90-2 (CANL) - H19-4 (CG)

Ignition switch off

200 Ω or higher

OK