Computers and Control Systems: Service Precautions
3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: PRECAUTION
PRECAUTION
NOTICE:
- Be careful because the fan may operate if the A/C switch is turned on or if the engine or inverter coolant becomes hot while the power switch is on (IG or READY) and the engine is stopped.
- When disconnecting the negative (-) battery cable, initialize the following systems after the terminal is reconnected.
1. PRECAUTIONS FOR INSPECTING HYBRID CONTROL SYSTEM
(a) Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
NOTE: After removing the service plug grip, turning the power switch on (READY) may cause a malfunction. Do not turn the power switch on (READY) unless instructed by the repair manual.
(b) After disconnecting the service plug grip, wait for at least 5 minutes before touching any of the high-voltage connectors or terminals.
HINT: Waiting for at least 5 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.
(c) After removing the inverter cover, wrap the interlock round terminal for the inverter cover with vinyl tape to prevent it from shorting to ground.
NOTE: Do not turn the power switch on (READY) with the inverter cover removed.
(d) Be sure to prevent water in the inverter reserve tank from entering the inverter.
(e) Wear protective goggles to prevent eye injury from electrolyte leakage when checking inside the HV battery.
(f) Check the voltage at the terminals in the inspection point in the inverter with converter assembly.
CAUTION: Be sure to wear insulated gloves.
(1) Remove the inverter cover Removal.
NOTICE:
- Prevent water in the inverter reserve tank from entering the inverter.
- Removing the inverter cover causes the MG ECU board to be exposed. Therefore, temporarily install the inverter cover for each area to be inspected.
(2) Measure the voltage according to the value(s) in the table below.
Standard voltage:
HINT: Set the tester to DC750 V or more to measure the voltage.
(g) When turning the power switch on (IG) during inspections, do not press the power switch with the brake pedal depressed.
CAUTION: Pressing the power switch with the brake pedal depressed causes the system to enter the READY-on state. This is very dangerous because high voltage may be applied to the inspection area.
(h) Turn the power switch off, wear insulated gloves, and disconnect the negative terminal of the auxiliary battery before touching any of the orange-colored wires of the high-voltage system.
(i) Turn the power switch off before performing any resistance checks.
(j) Turn the power switch off before disconnecting or reconnecting any connectors.
(k) When high-voltage connectors are removed, wrap the connectors with insulation tape to prevent them from contacting foreign objects.
2. PRECAUTIONS FOR HYBRID CONTROL SYSTEM ACTIVATION
(a) When the warning light is illuminated, or the auxiliary battery has been disconnected and reconnected, attempting to turn the power switch on (READY) may not start the system (the system may not enter the READY-on state) on the first attempt. If so, turn the power switch off and reattempt to start the hybrid system.
3. PRECAUTIONS FOR INSPECTING, REMOVING, OR INSTALLING INVERTER WITH CONVERTER ASSEMBLY
NOTE: Removing the inverter cover exposes the MG ECU board. Therefore, perform the following operation when inspecting, removing, or installing the inverter with converter assembly.
(a) When working on the inside of the inverter with converter assembly, temporarily install the inverter cover with a bolt as shown in the illustration.
NOTICE:
- Turn the bolt approximately twice to prevent deforming the inverter cover that will result from tightening the bolt excessively.
- Use a piece of cloth to prevent the inverter cover from coming into contact with the vehicle parts and being damaged.
- Do not apply load to the temporarily installed inverter cover.
HINT: Change the bolt position depending on the area where you are working inside the inverter with converter assembly.