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:
Suspension
SST
RECOMMENDED TOOLS
EQUIPMENT
TIRE AND WHEEL
RECOMMENDED TOOLS
EQUIPMENT
...
Cold Start Ignition Timing Performance
DESCRIPTION
This monitor will run when the engine is started at -10 to 50°C (14 to 122°F)
of the engine coolant
temperature. The DTC will set after the engine idling for 13 seconds (2 trip
detection logic).
The DTC is designed to monitor the idle air control at cold start. When the
...
Mass or Volume Air Flow Circuit/ Mass or Volume Air Flow Circuit Low Input/
Mass or Volume Air Flow Circuit High Input
DESCRIPTION
The Mass Air Flow (MAF) meter is a sensor that measures the amount of air
flowing through the throttle
valve. The ECM uses this information to determine the fuel injection time and to
provide appropriate airfuel
ratio. Inside the MAF meter, there is a heated platinum wire which is ...