Toyota Corolla (E120): Check and replace ecu
Notice
: start an inspection of the connector from the backside of the connector on the wire harness side with the connector connected to the ecu.
When no measurement condition is specified, perform the inspection with the engine stopped and also the ignition switch on.
- First check the ecu ground circuit. If it is faulty, repair it.
If it is normal, the ecu could be faulty. In this case, replace the ecu with one that functions normally and check if the symptoms appear.
- Measure the resistance between the ecu ground
terminal and body ground.
Resistance: 1 Ω or less

- Disconnect the ecu connector, check the ground terminals on the ecu side and wire harness side for bends and check the contact pressure.

Other materials:
Spiral cable sub–assy
Components
Replacement
Hint: components:
1. Precaution
2. Disconnect battery negative terminal
3. Place front wheels facing straight ahead
check that the front wheels are facing straight ahead.
4. Remove horn button assy
5. Remove steering wheel assy
sst 09950–50013 ...
Side mudguard sub–assy lh
Replacement
Hint:
use the same procedures for the rh side and lh side.
1. Remove side mudguard sub–assy lh
Using a clip remover, remove the 8 retainers and 9 clips.
using a moulding remover, remove the mudguard.
2. Install side mudguard sub–assy lh
Install the mudgu ...
Fail–safe chart
If any of the following codes is recorded, the ecm enters the fail–safe mode.
Check for intermittent problems
Hand–held tester only:
by putting the vehicle’s ecm in the check mode, the 1 trip detection logic is
possible instead of the
2 trip detection logic, and the sensitivity to de ...


