Toyota Corolla (E120) 2002–2008 Repair Manual / Introduction / How to troubleshoot ecu controlled
systems / General information
Toyota Corolla (E120): General information
There are many ecu controlled systems used in the corolla. In general, ecu controlled system are considered to be very intricate and require a high level of technical knowledge and expert skill to troubleshoot.
The fact is, however, that if you proceed by inspecting the circuits one by one, troubleshooting of these systems is not complex. If you have adequate understanding of the system and basic knowledge of electricity, the problem can be accurately diagnosed and fixed. This manual is designed based on the above principle to help service technicians perform accurate and effective troubleshooting, and is compiled for the following major ecu controlled systems: the troubleshooting procedures are described on the following pages.
System
- Sfi system
- Abs with ebd system
- Electronic controlled automatic transaxle [ect]
- Supplemental restraint system
- Audio system
- Combination meter
- Power door lock control system
- Wireless door lock control system
- Toyota vehicle intrusion protection system
- Cruise control system
For using hand–held tester
- Before using the tester, the tester’s operator manual should be read thoroughly.
- If the tester cannot communicate with the ecu controlled systems when you have connected the cable of tester to the dlc3, turned the ignition switch on and operated the tester, there is a problem on the vehicle side or tester side.
- If the communication is normal when the tester is connected to another vehicle, inspect the diagnosis data link line (bus line) or ecu power circuit of the vehicle.
- If the communication is still impossible when the tester is connected to another vehicle, the problem is probably in the tester itself, so perform the self test procedures outlined in the tester operator’s manual.
Other materials:
Driving the vehicle
The following procedures
should be observed to
ensure safe driving:
Driving procedure
■ Driving
1. With the brake pedal
depressed, shift the shift
lever to D.
2. Release the parking brake.
If the parking brake is in automatic
mode, the parking brake will be
released automatically.
3. Gradually re ...
Emission inspection and maintenance (I/M) programs
Some states have vehicle
emission inspection programs
which include OBD
(On Board Diagnostics)
checks. The OBD system
monitors the operation of
the emission control system.
If the malfunction indicator
lamp comes on
The OBD system determines
that a problem exists somewhere
in the emission control
sy ...
Safety Connect
*: If equipped
Safety Connect is a subscription-
based telematics
service that uses Global
Positioning System (GPS)
data and embedded cellular
technology to provide
safety and security features
to subscribers. Safety Connect
is supported by Toyota's
designated response
center, which operates 24
hour ...


