Toyota Sienna Service Manual: Engine Control System Malfunction
DTC C1201/51 Engine Control System Malfunction
DESCRIPTION
If trouble occurs the engine control system, the ECM transmits the abnormality to the skid control ECU.
The skid control ECU set this DTC and the skid control ECU prohibits TRAC and
VSC control. 
INSPECTION PROCEDURE
1 CHECK ENGINE CONTROL SYSTEM
(a) Check if the normal system code is recorded for engine control system.
Result 
REPLACE ECM
Open or Short Circuit in ABS Solenoid Relay Circuit
DESCRIPTION
The ABS solenoid relay is built in the brake actuator assembly. This relay
supplies power to each ABS
solenoid. If the initial check is OK, after the ignition switch is turned to t ...
ECM Communication Circuit Malfunction
DTC C1203/53 ECM Communication Circuit Malfunction
DESCRIPTION
The circuit is used to send TRAC and VSC control information from the skid
control ECU to the ECM, and
engine control information fr ...
Other materials:
Removal
1. DISCONNECT CABLE FROM NEGATIVE BATTERY
TERMINAL
2. REMOVE ENGINE UNDER COVER NO.1
3. DRAIN AUTOMATIC TRANSAXLE FLUID
(a) Remove the drain plug and gasket, and drain the
ATF.
(b) Install a new gasket and the drain plug.
Torque: 49 N*m (500 kgf*cm, 36 ft.*lbf)
4. REMOVE AUTOMATIC TRANSA ...
Right Front Wheel Speed Sensor Signal
DESCRIPTION
The speed sensor detects wheel speed and sends the appropriate signals to the
ECU. These signals are
used to control the ABS control system. The front and rear rotors have 48
serrations each.
When the rotors rotate, the magnetic field emitted by the permanent magnet in
t ...
Removal
1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL
2. REMOVE STEERING WHEEL NO. 2 LOWER COVER
3. REMOVE STEERING WHEEL NO. 3 LOWER COVER
4. REMOVE HONE BUTTON ASSEMBLY
5. REMOVE STEERING PAD SWITCH LH
Disconnect the connector.
Disconnect the connector of cruise control main
swi ...
