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 p/t squib (lh) circuit consists of the airbag sensor assy center and seat
belt pretensioner (lh).
It causes the srs to deploy when the srs deployment conditions are satisfied.
Dtc b0135/73 is recorded when a short is detected in the p/t squib (lh) circuit.
Wiring diagram
...
Have the malfunction repaired immediately. (vehicles with a smart key system)
After taking the specified steps to correct the suspected problem, check that
the warning message and light go off.
■Warning buzzer ...
On–vehicle inspection
1. Inspection throttle body idle speed control valve assy
Notice:
it is impossible to check the resister value and the operation
of isc valve by itself, because the isc valve
has an ic circuit inside it, which transforms the duty
signal from the ecm to the derive signal.
After check ...


