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:
Circuit description
The airbag sensor front lh circuit consists of the airbag sensor assy center
and airbag sensor front lh.
Dtc b1158/b1159/16 is recorded when malfunction is detected in the airbag sensor
front lh circuit.
Wiring diagram
...
Inspection procedure
1 Check ignition or starter switch assy
Check the ignition switch, as shown in the illustration and
table.
Standard:
2 Check fuse (ecu–b)
Remove the fuse from the instrument panel j/b.
check the continuity of the fuse.
Standard: continuity
3 Check relay (m ...
Inspection procedure
Hint:
read freeze frame data using the hand-held tester or the obd ii scan tool.
Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, it is
useful for determining whether
the vehicle was running or stopped, the engine was warmed up or not, the ...


