Hybrid Drive Systems: Service Precautions
NOTICE FOR HYBRID SYSTEM
Refer to the LEXUS Repair Manual for each work procedure.
1. PRECAUTIONS FOR HIGH-VOLTAGE CIRCUIT INSPECTION AND SERVICE
CAUTION: The vehicle has a hybrid system that operates at voltages up to 650 V. The hybrid system uses an HV battery that contains an electrolyte which is a strong alkali solution that includes potassium hydroxide. Be sure to follow the instructions to handle the system correctly. Failure to do so may result in serious injury or electrocution.
a. Technicians must undergo special training to be able to service and inspect the high-voltage system.
b. All high-voltage wire harnesses and connectors are colored orange. The HV battery and other high-voltage components have "High Voltage" caution labels. Do not carelessly touch these wires or components.
c. When there is a problem with the wire harness or connector of a high-voltage circuit, repairs to the harness or connector should not be attempted. Replace damaged or malfunctioning high voltage cables or connectors.
d. Before inspecting or servicing the high-voltage system, be sure to follow all safety measures, such as wearing insulated gloves and removing the service plug to prevent electrocution. Carry the removed service plug in your pocket to prevent other technicians from accidentally reconnecting it while you are servicing the vehicle.
NOTICE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
e. After removing the service plug grip, wait 10 minutes before touching any of the high-voltage connectors and terminals.
HINT: Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.
f. Before using insulated gloves, be sure to check them for cracks, tears and other types of damage by performing the following procedure.
g. When servicing the vehicle, do not carry metal objects like mechanical pencils or rulers that can be dropped accidentally and cause a short circuit.
h. Before touching a bare high-voltage terminal, wear insulated gloves and use a tester to make sure that the terminal voltage is 0 V.
i. After disconnecting or exposing a high-voltage connector or terminal, insulate it immediately using insulating tape.
j. Bolts and nuts for high-voltage terminals should be tightened firmly to the specified torque. Both insufficient and excessive torque can cause failure.
k. Use the "CAUTION: HIGH VOLTAGE DO NOT TOUCH" sign to notify other technicians that the high-voltage system is being inspected and/or repaired.
l. After servicing the high-voltage system and before reinstalling the service plug, check again that you have not left a part or tool inside, that the high-voltage terminals are firmly tightened, and that the connectors are correctly connected.
m. When performing work involving high-voltage wires, use either a tool wrapped with vinyl insulation tape or an insulated tool.
n. When installing hybrid system components such as the HV battery, make sure that the polarity of all connections is correct.
2. ACTIONS TO BE TAKEN FOR VEHICLES DAMAGED BY IMPACT
CAUTION: The vehicle has a hybrid system that operates at voltages of up to 650 V. The hybrid system uses an HV battery that contains an electrolyte which is a strong alkali solution that includes potassium hydroxide. Be sure to follow the instructions to handle the system correctly. Failure to do so may result in serious injury or electrocution.
a. Items to be prepared for the accident site
- Protective clothing (insulated gloves, rubber gloves, goggles and safety shoes)
- Saturated boric acid solution 20 liters (21.1 US qts, 17.6 Imp.qts) (obtain 800 g (1.76 lb) of boric acid powder, put it into a container, and dissolve it in water)
- Red litmus paper
- ABC fire extinguisher (effective against both oil flames and electrical flames)
- A shop rag or piece of cloth (for wiping off the electrolyte)
- Insulating tape (for insulating cables)
- Electrical tester
b. Actions to be taken at the accident site
CAUTION:
- Do not touch any bare cables that may have high-voltage. If a cable must be touched or if accidental contact is possible, wear insulated gloves and insulate the cable using insulating tape.
- If the vehicle catches on fire, use an ABC fire extinguisher to extinguish the fire. Trying to extinguish a fire using only a small amount of water can be more dangerous than effective. Use a substantial amount of water or wait for firefighters.
- Visually check the HV battery and the immediate area for any electrolyte leakage. Do not touch any leaked liquid because it could be highly alkaline electrolyte.
- Work on the vehicle only after the vehicle has been pulled out of the water.
1. Check the vicinity of the HV battery for any leakage of the electrolyte.
CAUTION:
- Do not touch any leaked liquid because it could be highly alkaline electrolyte. Wear rubber gloves and goggles, neutralize the liquid with saturated boric acid solution and then apply red litmus paper to the liquid. Check that the paper does not turn blue. Wipe the neutralized liquid with a shop rag or piece of cloth.
- If the electrolyte comes in contact with your skin, use a saturated boric acid solution or a large amount of water to wash it off. If the electrolyte comes in contact with an article of clothing, take it off immediately.
- If the electrolyte comes in contact with your eyes, call out loudly for help. Do not rub your eyes. Wash them immediately with a large amount of water and seek medical care.
2. If damage to any of the high-voltage components and cables is suspected, cut the high-voltage circuit using the following procedure.
CAUTION: Be sure to wear insulated gloves, goggles and safety shoes.
3. Turn the power switch off.
HINT: If the power switch cannot be turned off, remove the IG2- MAIN fuse from the No. 1 engine room relay block and junction block assembly. Confirm that the READY light is off.
4. Disconnect the cable from the negative (-) auxiliary battery terminal.
5. Wear insulated gloves and then remove the service plug grip.
NOTICE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
c. Moving the damaged vehicle
If any of the following conditions is met, tow the vehicle away using a tow truck.
NOTICE: When towing the vehicle, refer to the "PRECAUTIONS FOR TOWING REAR WHEEL DRIVE VEHICLES".
- One or more of the high-voltage components and cables are damaged.
- Components related to driving, the transmission, or the fuel system are damaged.
- The master warning light is on.
- The READY light does not come on when attempting to turn the power switch on (READY).
CAUTION: Before towing the vehicle away using a tow truck, disconnect the cable from the negative (-) auxiliary battery terminal and remove the service plug grip.
NOTICE: Perform the procedure below if the master warning light turns on, or there are abnormal noises, unusual smells, or strong vibrations while driving:
1. Park the vehicle in a safe place.
2. Apply the parking brake, and then move the shift lever to P.
3. Turn the power switch off, and disconnect the cable from the negative (-) auxiliary battery terminal.
4. Remove the service plug grip while wearing insulated gloves.
d. Actions required after moving the damaged vehicle
1. Procedure
If you see any liquid on the road surface, it could be highly alkaline electrolyte leakage.
Wear rubber gloves and goggles, neutralize the liquid with saturated boric acid solution, and then apply red litmus paper to the liquid. Check that the paper does not turn blue. Wipe up the neutralized liquid with a shop rag or piece of cloth.
e. Items to be prepared (when repairing a damaged vehicle)
- Protective clothing (insulated gloves, rubber gloves, goggles and safety shoes)
- Saturated boric acid solution 20 liters (21.1 US qts, 17.6 Imp.qts) (obtain 800 g (1.76 lb) of boric acid powder, put it into a container, and dissolve it in water)
- Red litmus paper
- A shop rag or piece of cloth (for wiping off the electrolyte)
- Insulating tape (for insulating cables)
- Electrical tester
f. Precautions to be observed when servicing a damaged vehicle
CAUTION: Always follow instructions to ensure safety.
1. Wear insulated or rubber gloves, goggles, and safety shoes.
2. Check the HV battery and immediate area for any electrolyte leakage.
CAUTION:
- Do not touch any leaked liquid because it could be highly alkaline electrolyte. Wear rubber gloves and goggles, neutralize the liquid with saturated boric acid solution and then apply red litmus paper to the liquid. Check that the paper does not turn blue. Wipe the neutralized liquid with a shop rag or piece of cloth.
- If the electrolyte comes in contact with your skin, use a saturated boric acid solution or a large amount of water to wash it off. If the electrolyte comes in contact with an article of clothing, take it off immediately.
- If the electrolyte comes in contact with your eyes, call out loudly for help. Do not rub your eyes. Wash them immediately with a large amount of water and seek medical care.
3. Do not touch any bare cables that could be high voltage cables. If a cable must be touched or if accidental contact is possible, follow the following instructions: 1) wear insulated gloves and goggles, 2) measure the voltage between the cable and body ground using an electrical tester, and 3) insulate the cable using insulating tape.
4. If damage to any of the high-voltage components and cables is suspected, cut the high-voltage circuit using the procedure below.
CAUTION: Do not touch any bare cables that may have high-voltage. If a cable must be touched or if accidental contact is possible, wear insulated gloves and insulate the cable using insulating tape.
5. Turn the power switch off.
HINT: If the power switch cannot be turned off, remove the IG2- MAIN fuse from the No. 1 engine room relay block and junction block assembly. Confirm that the READY light is off.
6. Disconnect the cable from the negative (-) auxiliary battery terminal.
7. Wear insulated gloves, and then remove the service plug.
NOTICE: After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
g. Precautions to be taken when disposing of an HV battery
1. When disposing of an HV battery, make sure to return it through an authorized collection agent who is capable of handling it safely. If the HV battery is returned via the manufacturer specified route, it will be returned properly and in a safe manner by an authorized collection agent.
CAUTION:
- Accidents such as electric shock may result if the HV battery is disposed of improperly or abandoned. Therefore, make sure to return all HV batteries through an authorized collection agent.
- After removing the HV battery, keep it away from water. Exposure to water may cause the HV battery to produce heat, resulting in a fire.
h. Precautions to be observed when towing
1. Tow the damaged vehicle with its front and rear wheels lifted off the ground.
CAUTION: Towing the damaged vehicle with its rear wheels on the ground will cause the motor to generate electricity. This electricity could, depending on the nature of the damage, leak and cause a fire.
i. Towing with the 4 wheels on the ground
CAUTION:
- If the vehicle needs to be towed using a rope with all 4 wheels on the ground, do not exceed 30 km/h (19 mph) and tow only for a short distance and then have the vehicle towed by a truck.
- Turn the power switch on (IG), and move the shift lever to N.
- Make sure not to turn the power switch off while the vehicle is being towed. Moving the shift lever to P may result in damage or an accident.
- If any abnormality is present in the damaged vehicle during towing, stop towing immediately.
3. PRECAUTIONS FOR TOWING REAR WHEEL DRIVE VEHICLES
a. Use one of the following methods to tow the vehicle.
b. If the vehicle has trouble with the chassis or drivetrain, use method 1 (flatbed truck).
NOTICE: Do not use any towing method other than those shown above.
c. If a tow truck is not available, in an emergency the vehicle may be temporarily towed using a cable or chain secured to the emergency towing eyelet(s). This should only be attempted on hard surfaced roads for short distances at low speeds.
A driver must be in the vehicle to steer and operate the brakes. The vehicle's wheels, drivetrain, axles, steering and brakes must be in good condition.
NOTICE: If the towing speed or distance exceeds the above limits, or the vehicle is towed in a backward direction with the wheels on the ground, the drivetrain or vehicle may be damaged.
1. Emergency towing procedure
1. Turn the power switch on (IG).
2. Depress the brake pedal and move the transmission shift lever to N.
3. Release the parking brake.
4. Release the brake pedal slowly.
NOTICE:
- Use extreme caution when towing the vehicle. Avoid sudden starts or erratic driving maneuvers which place excessive stress on the emergency towing eyelet and the cables or chains.
- If the hybrid system is off, the power assist for the brakes and steering will not function, making steering and braking more difficult.
- Do not turn off the power switch. Turning off the power switch may result in engagement of the steering lock, resulting in a hazardous situation or accident.
d. The towing methods shown below are dangerous and can damage the vehicle, so do not use them.
1. Do not tow the vehicle from the front wheels on the ground.
CAUTION: If the vehicle is towed with only the front wheels on the ground, the steering may move, causing the vehicle to become unstable.
NOTICE: If the vehicle is towed with only the rear wheels on the ground, the drivetrain may overheat and be damaged.
2. Do not use a sling-type towing method either from the front or rear.
NOTICE: If a sling-type tow truck is used, damage may occur to the vehicle body.