Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC U0029-00 (VSA Control Unit: With ACC)
DTC U0029-00 : CAN Communication Failure (Bus OFF)
NOTE:
- This DTC is stored by communication failure between the F-CAN line and the VSA modulator-control unit. When DTC U0029-00 is indicated, the F-CAN line has already returned to normal. Check for loose terminals and poor connections at the connectors. If the connectors are OK, clear the DTC and follow this troubleshooting.
- Troubleshoot any PGM-FI system DTCs first .
- Before you troubleshoot, review the general troubleshooting information .
| DTC Description | DTC |
|---|---|
| U0029-00 CAN Communication Failure (Bus OFF) |
DTC (VSA)
- Problem verification
-1. Turn the vehicle to the ON mode.
-2. Clear the DTC with the HDS.
-3. Turn the vehicle to the OFF (LOCK) mode.
-4. Turn the vehicle to the ON mode, then wait for a few seconds or more.
-5. Check for DTCs with the HDS.
DTC Description DTC U0029-00 CAN Communication Failure (Bus OFF) Is U0029-00 indicated?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting .
- CAN gateway system DTC check
-1. Check for CAN gateway system DTCs with the HDS.
DTC Description DTC Are any DTCs indicated?
YES
Go to indicated DTC's troubleshooting.
NO
Go to step 3.
- F-CAN circuit communication check
-1. Select the FUNCTION TEST in the CAN gateway with the HDS, then select the F-CAN Bus Connected Unit Check.
F-CAN Bus Connected Unit Check
Does the CAN gateway detect the VSA modulator-control unit Bus channels A and B?
'16-18 2/4-door: VSA modulator-control unit is Not Available for Bus A
Go to step 4.
'16-18 2/4-door: VSA modulator-control unit is Not Available for Bus B
Go to step 5.
'19-21 2/4-door: VSA modulator-control unit is Not Available for Bus A
Go to step 6.
'19-21 2/4-door: VSA modulator-control unit is Not Available for Bus B
Go to step 7.
'17-19 5-door: VSA modulator-control unit is Not Available for Bus A
Go to step 4.
'17-19 5-door: VSA modulator-control unit is Not Available for Bus B
Go to step 5.
'20-21 5-door: VSA modulator-control unit is Not Available for Bus A
Go to step 6.
'20-21 5-door: VSA modulator-control unit is Not Available for Bus B
Go to step 7.
VSA modulator-control unit Bus A and B are Available
Check for loose terminals and poor connections in the VSA modulator-control unit connector. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or replace the VSA modulator-control unit .
- Open wire check (F-CAN A_H, F-CAN A_L lines)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
CAN gateway 12P connector VSA modulator-control unit 46P connector -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode CAN gateway 12P connector: disconnected VSA modulator-control unit 46P connector: disconnected Test point 1 CAN gateway 12P connector (female terminals) No. 3: Test point 2 VSA modulator-control unit 46P connector No. 20 Test point 1 CAN gateway 12P connector (female terminals) No. 9: Test point 2 VSA modulator-control unit 46P connector No. 21 Is there 1.0 Ω or less ?
YES
The F-CAN A_H and F-CAN A_L wires are OK. Check for loose terminals in the VSA modulator-control unit 46P connector. If the symptom/indication is still present, replace the VSA modulator-control unit .
NO
Repair an open in the wire between the VSA modulator-control unit and the CAN gateway.
- Open wire check (F-CAN B_H, F-CAN B_L lines)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
CAN gateway 12P connector VSA modulator-control unit 46P connector -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode CAN gateway 12P connector: disconnected VSA modulator-control unit 46P connector: disconnected Test point 1 CAN gateway 12P connector (female terminals) No. 12: Test point 2 VSA modulator-control unit 46P connector No. 24 Test point 1 CAN gateway 12P connector (female terminals) No. 5: Test point 2 VSA modulator-control unit 46P connector No. 25 Is there 1.0 Ω or less ?
YES
The F-CAN B_H and F-CAN B_L wires are OK. Check for loose terminals in the VSA modulator-control unit 46P connector. If the symptom/indication is still present, replace the VSA modulator-control unit .
NO
Repair an open in the wire between the VSA modulator-control unit and the CAN gateway.
- Open wire check (F-CAN A_H, F-CAN A_L lines)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
CAN gateway 16P connector VSA modulator-control unit 46P connector -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode CAN gateway 16P connector: disconnected VSA modulator-control unit 46P connector: disconnected Test point 1 CAN gateway 16P connector (female terminals) No. 3: Test point 2 VSA modulator-control unit 46P connector No. 20 Test point 1 CAN gateway 16P connector (female terminals) No. 11: Test point 2 VSA modulator-control unit 46P connector No. 21 Is there 1.0 Ω or less ?
YES
The F-CAN A_H and F-CAN A_L wires are OK. Check for loose terminals in the VSA modulator-control unit 46P connector. If the symptom/indication is still present, replace the VSA modulator-control unit .
NO
Repair an open in the wire between the VSA modulator-control unit and the CAN gateway.
- Open wire check (F-CAN B_H, F-CAN B_L lines)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connectors.
CAN gateway 16P connector VSA modulator-control unit 46P connector -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode CAN gateway 16P connector: disconnected VSA modulator-control unit 46P connector: disconnected Test point 1 CAN gateway 16P connector (female terminals) No. 6: Test point 2 VSA modulator-control unit 46P connector No. 24 Test point 1 CAN gateway 16P connector (female terminals) No. 14: Test point 2 VSA modulator-control unit 46P connector No. 25 Is there 1.0 Ω or less ?
YES
The F-CAN B_H and F-CAN B_L wires are OK. Check for loose terminals in the VSA modulator-control unit 46P connector. If the symptom/indication is still present, replace the VSA modulator-control unit .
NO
Repair an open in the wire between the VSA modulator-control unit and the CAN gateway.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.