Toyota Sienna Service Manual: Open in Pump Motor Circuit
DTC C1251/51 Open in Pump Motor Circuit
DESCRIPTION
The motor relay (semiconductor relay) is housed in the brake actuator assembly and drives the pump motor based on a signal from the skid control ECU.
WIRING DIAGRAM
Refer to DTCs C0273/13 and C0274/14 (See page BC-31).
INSPECTION PROCEDURE
HINT: After step 1 is complete, start the inspection from step 2 when using the intelligent tester, and from step 3 when not using the intelligent tester.
1 INSPECT SKID CONTROL ECU (GND TERMINAL CONTINUITY)
(a) Disconnect the skid control ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance
2 PERFORM ACTIVE TEST BY INTELLIGENT TESTER (ABS MOTOR RELAY)
(a) Reconnect the skid control ECU connector.
(b) Connect the intelligent tester to the DLC3.
(c) Turn the ignition switch to the ON position and turn the intelligent tester main switch on.
(d) Start the engine.
(e) Select the ACTIVE TEST mode on the intelligent tester.
ABS: 
(f) Check operating sound of the ABS motor when operating it with the intelligent tester.
OK: The operating sound of the ABS motor is heard.
3 RECONFIRM DTC
(a) Clear the DTCs (See page BC-10).
(b) Start the engine.
(c) Drive the vehicle at the speed of 6 km/h (4 mph) or more.
(d) Check that the same DTC is recorded (See page BC- 10).
HINT:
- Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.
- If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU, with the ignition switch on and the stop light switch off, the ECU performs selfdiagnosis of the motor and solenoid circuits.
Result 
HINT:
- If any DTCs are output while jiggling a connector or wire harness of the brake actuator (skid control ECU), inspect and repair the connector or wire harness.
- If the normal system code is output, slightly jiggle the connectors, wire harnesses, and fuses of the brake actuator assembly. Make sure that no DTCs are output.
- These DTCs may be stored due to a malfunction in the connector terminal connection, etc.
REPLACE BRAKE ACTUATOR ASSEMBLY
Open in Stop Light Switch Circuit
DTC C1249/49 Open in Stop Light Switch Circuit
DESCRIPTION
This skid control ECU inputs the stop light switch signal and detects the
status of brake operation.
The skid control ECU has an open ...
ABS Warning Light Remains ON
DESCRIPTION
If any of the following is detected, the ABS warning light remains on.
The skid control ECU connectors are disconnected from the skid control
ECU.
There is a malfunction in the s ...
Other materials:
Communication Error of Yaw Rate Sensor
DTC U0123 Communication Error of Yaw Rate Sensor
DESCRIPTION
This circuit detects the yaw rate of the vehicle and transmits its signal to
the skid control ECU and
distance control ECU.
DTC No.
DTC Detection Condition
Trouble Area
U0123
While the dynamic ...
How to proceed with
troubleshooting
HINT:
The intelligent tester can be used in steps 2, 3, 4, 6 and 9.
1 VEHICLE BROUGHT TO WORKSHOP
2 CONNECT INTELLIGENT TESTER TO DLC3
HINT:
If the display indicates a communication fault in the tester,
inspect the DLC3.
3 CHECK DTC AND FREEZE FRAME DATA
Check for DTC(s) and freeze frame ...
Diagnostic trouble code chart
Look for output Diagnostic Trouble Codes (DTCs) (from the
DTC checks) in the appropriate section's Diagnostic Trouble
Code Chart. Use the chart to determine the trouble area and
the proper inspection procedure. A description of each of the
chart's columns is shown in the table below.
Ite ...
