Never attempt to disconnect battery cables while engine is running.
Before connecting or disconnecting the ECM harness connector, turn ignition switch OFF and disconnect negative battery cable. Failure to do so may damage the ECM because battery voltage is applied to ECM even if ignition switch is turned OFF.
Before removing parts, turn ignition switch OFF and then disconnect battery ground cable.
Never disassemble ECM.
If a battery cable is disconnected, the memory will return to the ECM value.The ECM will now start to self-control at its initial value. Thus, engine operation can vary slightly in this case. However, this is not an indication of a malfunction. Never replace parts because of a slight variation.
If the battery is disconnected, the following emission-related diagnostic information will be lost within 24 hours.
Diagnostic trouble codes
1st trip diagnostic trouble codes
Freeze frame data
1st trip freeze frame data
System readiness test (SRT) codes
When connecting ECM harness connector, fasten (B) it securely with a lever (1) as far as it will go as shown in the figure.
When connecting or disconnecting pin connectors into or from ECM, never damage pin terminals (bends or break).Check that there are not any bends or breaks on ECM pin terminal, when connecting pin connectors.
Securely connect ECM harness connectors.A poor connection can cause an extremely high (surge) voltage to develop in coil and condenser, thus resulting in damage to ICs.
Keep engine control system harness at least 10 cm (4 in) away from adjacent harness, to prevent engine control system malfunctions due to receiving external noise, degraded operation of ICs, etc.