Toyota Corolla (E120) 2002–2008 Repair Manual / Introduction / How to troubleshoot ecu controlled
systems / Customer problem analysis
Toyota Corolla (E120): Customer problem analysis
Hint
:
- in troubleshooting, the problem symptoms must be confirmed accurately, meaning that all preconceptions must be set aside in order to make an accurate judgement. To ascertain what the problem symptoms are, it is extremely important to ask the customer about the problem and conditions when it occurred.
- The following 5 items are important points in the problem analysis. Past problems which are thought to be unrelated and the repair history, etc. May also help in some cases. Therefore, as much information as possible should be gathered and its relationship with the problem symptoms should be correctly ascertained for use as reference in troubleshooting. A customer problem analysis table is provided for your use in the diagnostics section for each system.

(Sample) supplemental restraint system check sheet.

Other materials:
Steering wheel audio switches
Some audio features can be controlled using the switches on the steering wheel.
Operation may differ depending on the type of audio system or navigation system.
For details, refer to the manual provided with the audio system or navigation system.
Operating the audio system using the steering whe ...
Optimal use of the multimedia system
On the “Sound Settings” screen, sound quality (Treble/Mid/ Bass), volume balance
can be adjusted.
How to adjust the sound settings and sound quality
1 2 3 Select “-” or “+” to adjust the treble, mid or bass to a level between
-5 and 5.
4 5 Select “Front” or “Rear” to adjus ...
Circuit description
When the ignition switch is turned on, battery positive voltage is applied to
the coilwhich closes the contacts
of the efi main relay (marked: efi) and supplies power to terminal +b of the ecm.
This signal causes current to flow to the coil, closing the contacts of the efi
relay and supplyin ...


