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:
Monitor description
While the engine is being cranked, the battery positive voltage is applied to
terminal sta of the ecm.
If the ecm detects the starter control signal (sta) while the vehicle is
driving, it will conclude that there is
a fault in the starter control circuit. The ecm will turn on the mil and a d ...
Heater control & accessory assy
Replacement
1. Remove console panel upper
2. Remove instrument cluster finish panel
3. Remove heater control & accessory assy
Release the 2 fitting claws and pull out the heater control
& accessory assy.
Using a screwdriver, open the claw of the cable clamp and
dis ...
Circuit description
The ignition switch provides circuit power and the ecm provides the circuit
ground that illuminates the mil.
Mil operation is checked visually:
it should be illuminated when the ignition is first turned on. If the mil is off
all of the time or on all of the time,
use the procedure below to ...