Catera V6-3.0L VIN R (1997)
The ECM can supply 5 volts or 12 volts to the various sensors or switches. This is done through pull-up resistors to the regulated power supplies within
the ECM. The resistance is so high in value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter
will not give an accurate reading because the resistance is too low. Therefore, a digital voltmeter (J 39200) with at least 10 megohms input impedance is
required in order to ensure accurate voltage readings.
The ECM controls the output circuits such as the injectors, the relays, the IAC, etc. by controlling the ground or the power feed circuit through the
transistors or a device called an Output Driver Module.
ECM Learning Ability
The ECM has a learning ability which allows for making corrections for minor variations in the fuel system in order to improve the driveability. If the
battery cable is disconnected, the learning process resets. A change may be noted in the vehicle's performance. To teach the vehicle, ensure that the
engine is at the normal operating temperature, then turn ON the ignition key.
Idle Learn
Another method to teach the vehicle to idle is to drive the vehicle at part throttle, with moderate acceleration. You may also operate the vehicle at idle
conditions until the normal performance returns.