Troubleshooting for Communication Bus Off
Troubleshooting for Communication Bus Off
NOTE:
Be sure to perform Initial Inspection and Diagnostic Overview CAN Communication Check
before performing this flow.
Circuit Diagram
Refer to CAN Communication System Circuit Diagram CAN Communication System Circuit Diagram.
Diagnosis Procedure
When "CAN Communication Bus Off" is detected in any control modules, or when it is not possible to communicate with any control modules / sensors with CAN by using SUZUKI scan tool, check the following procedure.
1) Connect oscilloscope or SUZUKI scan tool to DLC with ignition mode in "OFF".
2) Using oscilloscope or oscilloscope function of SUZUKI scan tool, observe waveform in the following condition when ignition mode is in "ON".
CAN Communication System Circuit Diagram CAN Communication System Circuit Diagram
3) Compare observed signal waveform and waveforms given as "Reference Waveform:". Find the most similar signal waveform and identify the trouble system and trouble cause.
4) Perform troubleshooting.
Reference Waveform
NOTE:
- The tables below show waveforms observed with oscilloscope function of SUZUKI scan tool. They are provided as reference examples.
- Waveforms in "Examples of abnormal waveforms" are selected examples of CAN communication waveforms seen when an abnormality occurs. However, these waveform may not be exactly the same in appearance as observed waveforms. Therefore, to identify an abnormality, select the waveform that is the most similar to the observed waveform from Examples of abnormal waveforms.
Normal waveform
Examples of abnormal waveforms
Troubleshooting
NOTE:
- Before diagnosing trouble, be sure to check equipment of vehicle being serviced as well as control modules and sensors connected to CAN communication line.
- Before using scan tool, read its Operator's (Instruction) Manual to know how to use it.
- When performing "Communication Bus Check" by using SUZUKI scan tool in this troubleshooting, refer to Judgment of Communication Bus Check.
1. CAN communication circuit check
Disconnect negative (-) cable at battery.
Disconnect connectors from all the following control modules and sensors communicated by CAN. CAN Communication System Circuit Diagram
Check for proper connection to each CAN communication circuit at all control module / sensor (communicated by CAN) connectors and DLC.
If connections are OK, check the following points of each CAN communication circuit based on results found in Steps 2) of Diagnosis Procedure.
open
short to power circuit
short to ground circuit
short to each other CAN communication wire
Is it in good condition?
YES
Go to Step 2.
NO
Repair or replace defective wire harness.
2. ECM terminating resistance check
Connect "E01" connector to ECM.
Measure resistance between "E09-3" and "E09-16" terminals of ESP (R) control module connector.
Is resistance 114 - 134 ?
YES
Go to Step 3.
NO
Substitute a known-good ECM and recheck DTC. Service and Repair
3. Combination meter terminating resistance check
Connect connector to combination meter.
Measure resistance between "G211-6" and "G211-14" terminals of DLC.
Is resistance 114 - 134 ?
YES
2WD model: Go to Step 5.
4WD model: Go to Step 4.
NO
Substitute a known-good combination meter and recheck DTC. Service and Repair
4. Combination meter, BCM, ESP (R) control module, ECM, 4WD control module and keyless start control module communication check
Connect connectors to keyless start control module, 4WD control module, BCM and ESP (R) control module.
Connect negative (-) cable at battery.
Push engine switch to change ignition mode to "ON".
Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
Check that CAN communication is in normal condition for combination meter, BCM, ESP (R) control module, ECM, keyless start control module and 4WD control module.
Is communication normal?
YES
Perform communication check according to connected control modules / sensors.
NO
Go to Step 6.
5. Combination meter, BCM, ESP (R) control module, ECM and keyless start control module communication check
Connect connectors to keyless start control module, BCM and ESP (R) control module.
Connect negative (-) cable at battery.
Push engine switch to change ignition mode to "ON".
Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
Check that CAN communication is in normal condition for combination meter, BCM, ESP (R) control module, ECM, and keyless start control module.
Is communication normal?
YES
Perform communication check according to connected control modules / sensors.
NO
Go to Step 7.
6. 4WD control module communication check
Push engine switch to change ignition mode to "OFF".
Disconnect 4WD control module connector.
Connect the following terminals of 4WD control module connector using service wires.
Between "L14-20" and "L14-23" terminals
Between "L14-22" and "L14-26" terminals
Push engine switch to change ignition mode to "ON".
Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
Check that CAN communication is in normal condition for combination meter, BCM, ESP (R) control module, ECM, and keyless start control module.
Is communication normal?
YES
Substitute a known-good 4WD control module and recheck DTC. Service and Repair
NO
Go to Step 7.
7. BCM communication check
Push engine switch to change ignition mode to "OFF".
For 4WD model, disconnect service wires from 4WD control module connector, and then connect connector to 4WD control module.
Disconnect "L03" and "E05" connectors from BCM.
Connect the following terminals of BCM connectors using service wires.
Between "L03-5" and "E05-5" terminals
Between "L03-4" and "E05-6" terminals
Push engine switch to change ignition mode to "ON".
Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
Check that CAN communication is in normal condition for combination meter, ECM, keyless start control module, ESP (R) control module and 4WD control module (4WD model).
Is communication normal?
YES
Substitute a known-good BCM and recheck DTC. Service and Repair
NO
Go to Step 8.
8. ESP (R) control module communication check
Push engine switch to change ignition mode to "OFF".
Disconnect service wires from BCM connectors, and then connect connectors to BCM.
Disconnect ESP (R) control module connector.
Connect the following terminals of ESP (R) control module connector using service wires.
Between "E09-2" and "E09-3" terminals
Between "E09-15" and "E09-16" terminals
Push engine switch to change ignition mode to "ON".
Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
Check that CAN communication is in normal condition for combination meter, BCM, ECM, keyless start control module and 4WD control module (4WD model).
Is communication normal?
YES
Substitute a known-good ESP (R) control module and recheck DTC. ESP Hydraulic Unit / Control Module Assembly Removal and Installation
NO
Go to Step 9.
9. Combination meter communication check
Push engine switch to change ignition mode to "OFF".
Disconnect service wires from ESP (R) control module connector, and then connect connector to ESP (R) control module.
Replace combination meter. Service and Repair
Push engine switch to change ignition mode to "ON".
Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
Check that CAN communication is in normal condition for combination meter, BCM, ESP (R) control module, ECM, keyless start control module and 4WD control module (4WD model).
Is communication normal?
YES
End. (combination meter was faulty)
NO
Go to Step 10.
10. ECM communication check
Push engine switch to change ignition mode to "OFF".
Replace ECM. Service and Repair
Push engine switch to change ignition mode to "ON".
Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
Check that CAN communication is in normal condition for combination meter, BCM, ESP (R) control module, ECM, keyless start control module and 4WD control module (4WD model).
Is communication normal?
YES
End. (ECM was faulty)
NO
Substitute a known-good keyless start control module and recheck DTC. Service and Repair
Communication Check
Steering angle sensor
1) Push engine switch to change ignition mode to "OFF".
2) Connect connector to steering angle sensor.
3) Push engine switch to change ignition mode to "ON".
4) Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
5) Confirm that CAN communication already connecting the control modules, sensor and steering angle sensor is operating normally.
6) If any malfunction is found, substitute a known-good steering angle sensor and recheck DTC. Steering Angle Sensor Removal and Installation
SDM
7) Push engine switch to change ignition mode to "OFF".
8) Connect "G11" connector to SDM.
9) Push engine switch to change ignition mode to "ON".
10) Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
11) Confirm the CAN communication that control modules, sensors and SDM have been already connected on is in normal condition.
12) If any malfunction is found, substitute a known-good SDM and recheck DTC. SDM Removal and Installation
HVAC control module
13) Push engine switch to change ignition mode to "OFF".
14) Connect connector to HVAC control module.
15) Push engine switch to change ignition mode to "ON".
16) Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
17) Confirm the CAN communication that control modules, sensors and HVAC control module have been already connected on is in normal condition.
18) If any malfunction is found, substitute a known-good HVAC control module and recheck DTC. HVAC Control Module Removal and Installation
Rain / light sensor
19) Push engine switch to change ignition mode to "OFF".
20) Connect connector to rain / light sensor.
21) Push engine switch to change ignition mode to "ON".
22) Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
23) Confirm the CAN communication that control modules, sensor and rain / light sensor have been already connected on is in normal condition.
24) If any malfunction is found, substitute a known-good rain / light sensor and recheck DTC. Removal and Replacement
TCM (CVT model)
25) Push engine switch to change ignition mode to "OFF".
26) Connect "E19" connector to TCM.
27) Push engine switch to change ignition mode to "ON".
28) Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
29) Confirm the CAN communication that control modules, sensors and TCM have been already connected on is in normal condition.
30) If any malfunction is found, substitute a known-good TCM and recheck DTC. Service and Repair
P/S control module
31) Push engine switch to change ignition mode to "OFF".
32) Connect "E10" connector to P/S control module.
33) Push engine switch to change ignition mode to "ON".
34) Select "Communication Bus Check" under "Bus Check" menu of SUZUKI scan tool.
35) Confirm the CAN communication that control modules, sensors and P/S control module have been already connected on is in normal condition.
36) If any malfunction is found, substitute a known-good P/S control module and recheck DTC. Service and Repair
Judgment of Communication Bus Check
When performing "Communication Bus Check" by using SUZUKI scan tool, refer to the following table for judgment.
