Toyota Sienna Service Manual: 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 skid control ECU internal circuit.
- There is an open in the harness between the combination meter and the skid control ECU.
HINT: In some cases, the intelligent tester cannot be used when the skid control ECU is abnormal.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED
(a) Check the skid control ECU connector's connecting condition.
OK: The connector should be securely connected.
2 INSPECT BATTERY
(a) Check the battery voltage.
Standard voltage: 11 to 14 V
2 INSPECT BATTERY
(a) Check the battery voltage.
Standard voltage: 11 to 14 V
3 INSPECT SKID CONTROL ECU (IG1 TERMINAL VOLTAGE)
(a) Disconnect the skid control ECU connector.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage 
4 INSPECT SKID CONTROL ECU (GND TERMINAL CONTINUITY)
(a) Turn the ignition switch off.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance
5 CHECK HARNESS AND CONNECTOR (BETWEEN SKID CONTROL ECU AND COMBINATION METER ASSEMBLY)
(a) Disconnect the combination meter connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance 
6 INSPECT COMBINATION METER ASSEMBLY
(a) Check the combination meter (See page ME-4).
HINT: If troubleshooting has been carried out according to the PROBLEM SYMPTOMS TABLE, refer back to the table and proceed to the next step before replacing the part (See page BC-7).
REPLACE BRAKE ACTUATOR ASSEMBLY
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 contro ...
ABS Warning Light does not Come ON
WIRING DIAGRAM
See page BC-47.
INSPECTION PROCEDURE
1 INSPECT ABS WARNING LIGHT
(a) Disconnect the skid control ECU connector.
(b) Turn the ignition switch to the ON position.
(c) Check that ...
Other materials:
Engine Coolant Temperature Circuit
DESCRIPTION
A thermistor is built into the Engine Coolant Temperature (ECT) sensor, of
which the resistance value
varies according to the ECT.
The structure of the sensor and its connection to the ECM are the same as those
of the Intake Air
Temperature (IAT) sensor.
HINT:
When any ...
Unlock Warning Switch Circuit
DESCRIPTION
The unlock warning switch detects if the key is in the ignition key cylinder.
The unlock warning switch turns on when the key is inserted into the ignition
key cylinder and turns off
when the key is removed from the cylinder.
The body ECU is connected to the unlock warning swit ...
On-vehicle inspection
1. INSPECT COOLER CONDENSER CORE
(a) If the fin of the cooler condenser core is dirty, clean
it with water and dry it with compressed air.
NOTICE:
Do not damage the fin of the cooler condenser
core.
(b) If the fin of the cooler condenser core is bent, make
it straight using a screwdriver or p ...
