DTC C1428: Motor Circuit [10/2018 - ]: Procedure

1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

   OK

   The connector is securely connected.

2. Disconnect the A37 skid control ECU (brake booster with master cylinder assembly) connector.
3. Disconnect the A48 brake actuator assembly connector.
4. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A37-40 (+BM) - A48-10 (+BM)	Always	Below 1 Ω
   A37-40 (+BM) or A48-10 (+BM) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  2

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A48-1 (MGND) - Body ground	Always	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Brake Actuator Assembly)

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)