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:
Tire pressure warning system
Your vehicle is equipped with a tire pressure warning system that uses
tire pressure warning valves and transmitters to detect low tire inflation
pressure before serious problems arise.
Vehicles with compact spare tire: The compact spare tire is not
equipped with the tire pressure warning valve ...
Headlight dimmer switch
COMPONENTS
REMOVAL
1. REMOVE STEERING COLUMN LOWER COVER
2. REMOVE STEERING COLUMN UPPER COVER
3. REMOVE HEADLIGHT DIMMER SWITCH ASSEMBLY
Disconnect the connector.
Release the claw fitting and remove the headlight
dimmer switch assembly.
INSPECTION
1. HEADLIGHT DI ...
Disassembly
1. REMOVE AIR REFINER ELEMENT
(a) Release the 2 claw fittings and remove the air filter
sub-assembly.
(b) Remove the air refiner element from the air filter
cover plate.
2. REMOVE COOLING UNIT DAMPER SERVO SUBASSEMBLY
(a) Remove the 3 screws and the cooling unit damper
servo sub-a ...
