DTC U0129: Lost Communication with Brake System Control Module [08/2015 - ]: Procedure

1. Reconfirm DTCs.

   HINT: 

   If DTC U1002 is output from PM2 Gateway of the power management control ECU, this indicates a sub bus 12 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in sub bus 12.

   Result

   Result	Proceed to
   U1002 is not output from power management control ECU (Techstream display/PM2 Gateway)	A
   U1002 is output from power management control ECU (Techstream display/PM2 Gateway)	B

B → Refer to   5 

A: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.

   OK

   DTC C1241 is not output.

NG → Refer to   6 

OK: Go to next step 

1. Disconnect the cable from the negative (-) auxiliary battery terminal.
2. Disconnect the A58 brake booster with master cylinder assembly (skid control ECU) connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A58-35 (CA2H) - A58-34 (CA2L)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Brake Booster with Master Cylinder Assembly)

NG → REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (SKID CONTROL ECU) 

OK → Refer to   4