DESCRIPTION
DTC No. | DTC Detection Condition | Trouble Area |
---|---|---|
U0129 | No communication from the brake booster with master cylinder assembly (skid control ECU) continues. |
|
Tech Tips
This diagnosis procedure is for when DTC U0129 is output only by the power management control ECU (Techstream display: Hybrid Control).
WIRING DIAGRAM
INSPECTION PROCEDURE
Note
Before measuring the resistance of the CAN bus, turn the power switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work Click here.
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 here.
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the power switch on (IG) and wait at least 60 seconds,
After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.
Tech Tips
Operating the power 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
RECONFIRM DTC OUTPUT
Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
OK |
---|
DTC C1241 is not output. |
NG |
GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here |
OK |
RECONFIRM DTC OUTPUT
Reconfirm DTCs.
Tech Tips
If the power management control ECU outputs DTC U0100 and DTC U0129, check the branch circuit of sub bus 15.
Result | ||||||
---|---|---|---|---|---|---|
|
B |
GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here |
A |
CHECK FOR OPEN IN CAN BUS LINES (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY BRANCH LINE)
Disconnect the cable from the negative (-) auxiliary battery terminal.
Disconnect the brake booster with master cylinder assembly (skid control ECU) connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
*a | Front view of wire harness connector (to Brake Booster with Master Cylinder Assembly (Skid Control ECU)) |
NG |
REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) |
OK |
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here