Toyota Sienna Service Manual: How to troubleshoot ecu controlled systems

Vehicle lift and support locations

1. NOTICE ABOUT VEHICLE CONDITION WHEN JACKING UP VEHICLE (a) The vehicle must be unloaded before jacking up/ lifting up the vehicle. Never jack up/lift up a heavily loaded vehicle. (b) When re ...

General information

A large number of ECU controlled systems are used in the SIENNA. In general, ECU controlled systems are considered to be very intricate, requiring a high level of technical knowledge to troubleshoo ...

Other materials:

Open in ABS Motor Relay Circuit
DESCRIPTION The ABS motor relay supplies power to the ABS pump motor. While the ABS is activated, the ECU turns the motor relay on and operates the ABS pump motor. If the voltage supplied to the motor relay (+BM) is below the DTCs detection threshold due to low voltage from the battery ...

Starting the engine
Shift the shift lever to P and apply the brakes. Touch the Toyota emblem side of the electronic key to the engine switch. An alarm will sound to indicate that the start function cannot detect the electronic key that is touched to the engine switch if any of the doors is opened ...

Engine Coolant Temperature Circuit Range / Performance Problem
DTC P0116 Engine Coolant Temperature Circuit Range / Performance Problem DESCRIPTION Refer to DTC P0115 DTC No. DTC Detection Condition Trouble Area P0116 ECTs as listed below are nearly same (2 trip detection logic):  ECT when engine is start ...