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HYBRID VEHICLES Hybrid vehicles are maintained and serviced in the same way as conventional vehicles, except for the hybrid components. The latter includes the high voltage battery pack and circuits, which must be respected when doing any service on the vehicles. Other services to hybrid vehicles are normal services that must be completed in a different way. For the most part, service to the hybrid system is not something that is done by technicians, unless they are certified to do so by the automobile manufacturer. Keep in mind that a hybrid has nearly all of the basic systems as a conventional vehicle and these are diagnosed and serviced in the same way. Through The engines used in hybrids are modified versions of engines found in other models offered by the manufacturer. Other than fluid checks and changes, there is little maintenance required on these engines. However, there is less freedom in deciding the types of fluids that can be used and the parts that can replace the original equipment. Hybrids are not very forgiving. Always use the exact replacement parts and the fluids specified by the manufacturer. Typically, the weight of the engine oil used in a hybrid is very light. If heavier oil is used, the computer may see this as a problem and prevent the engine from starting. The heavier oil may cause an increase in the current required to crank the engine. If the computer senses very high current draw while attempting to crank the engine, it will open the circuit in response. Special coolants are required in most hybrids because the coolant cools not only the engine, but also the inverter assembly. Cooling the inverter is important and checking its coolant condition and level is an additional check during PM. The cooling systems used in some hybrids feature electric pumps and storage tanks. The tanks store heated coolant and can cause injury if you are not aware of how to carefully check them. The battery cooling system may need to be serviced at regular intervals. There is a filter in the duct work from the outside of the vehicle to the battery box. This filter needs to be periodically changed. If the filter becomes plugged, the temperature of the battery will rise to dangerous levels. In fact, if the computer senses high temperatures it may shut down the system. An understanding of how the hybrid vehicle operates, you can safely service them. One of the things to pay attention to is the stop start feature. You need to know when the engine will normally shut down and restart. Without this knowledge, or the knowledge of how to prevent this, the engine may start on its own when you are working under the hood. Needless to say, this can create a safety hazard. There is a possibility that your hands or something else can be trapped in the rotating belts or hit by a cooling fan. Unless the system is totally shut down, the engine may start at any time when its control system senses that the battery needs to be recharged. In addition, there is a possibility that the system will decide to power the vehicle by electric only. When it does this, there is no noise, just a sudden movement of the vehicle. This can scare you and can be dangerous. To prevent both of these incidences, always remove the key from the ignition. Make sure the "READY" lamp in the instrument cluster is off; this lets you know the system is also off. +++An example of some of the warning lights in a hybrid vehicle. CHECK HYBRID SYSTEM ODO 241 MILES Multi-information display READY light READY Malfunction indicator lamp Discharge warning light HV battery warning light Master warning light +++ The hot coolant storage tank for Toyota hybrids. Coolant heat storage water pump, Electrical connector, Coolant heat storage tank Maintenance Maintenance of a hybrid vehicle is much the same as a conventional one. Care needs to be taken to avoid anything orange while carrying out the maintenance procedures. The computer-controlled systems are extremely complex, especially in assist and full hybrids, and are very sensitive to voltage changes. This is why the manufacturers recommend a thorough inspection of the auxiliary battery and connections every 6 months. A normal part of PM is checking power steering and brake fluids. The power steering systems used by the manufacturers vary; some have a belt-driven pump, some have an electrically driven pump, and others have a pure electric and mechanical steering gear. Each variety requires different care; therefore, always check the service manual for the specific model before doing anything to these systems. Also, keep in mind that some hybrids use the power steering pump as the power booster for the brake system. Hybrids are all about fuel economy and reduced emissions. Everything that would affect these should be checked on a regular basis. Items such as tires, brakes, and wheel alignment can have a negative effect, and owners of hybrids will notice the difference. These owners are constantly aware of their fuel mileage due to the displays on the instrument panel. ADDITIONAL PM CHECKS The following PM checks are in addition to those items specified by the manufacturer. These should be performed at these suggested time intervals to help ensure safe and dependable vehicle operation. Time: While operating the vehicle ¦ Pay attention to and note any changes in the sound of the exhaust or any smell of exhaust fumes in the vehicle. ¦ Check for vibrations in the steering wheel. Notice any increased steering effort or looseness in the steering wheel. ¦ Notice if the vehicle constantly turns slightly or pulls to one side of the road. ¦ When stopping, listen and check for strange sounds, pulling to one side, increased brake pedal travel, or hard-to-push brake pedal. ¦ If any slipping or changes in the operation of the transmission occur, check the transmission fluid level. ¦ Check for fluid leaks under the vehicle. (Water dripping from the air-conditioning system after use is normal.) ¦ Check the automatic transmission's park function. ¦ Check the parking brake. Time: At least monthly ¦ Check the operation of all exterior lights, including the brake lights, turn signals, and hazard warning flashers. Time: At least twice a year ¦ Check the pressure in the spare tire. ¦ Check headlight alignment. ¦ Check the muffler, exhaust pipes, and clamps. ¦ Inspect the lap/shoulder belts for wear. ¦ Check the radiator, heater, and air-conditioning hoses for leaks or damage. Time: At least once a year ¦ Lubricate all hinges and all outside key locks. ¦ Lubricate the rubber weather strips for the doors. ¦ Clean the body's water drain holes. ¦ Lubricate the transmission controls and linkage. TERMINOLOGY: American Petroleum Institute (API) Automatic transmission fluid (ATF) Coolant, Core, Core charge Crude oil Dipstick Energy-conserving oil Multi-viscosity National Lubricating Grease Institute (NLGI) Polyglycol Repair order (RO) Serpentine belt Society of Automotive Engineers (SAE) Sublet repair V-belts Vehicle identification number (VIN) Viscosity V-ribbed belts Zerk fitting SUMMARY ¦ A repair order (RO) is a legal document used for many purposes. ¦ An RO includes a cost estimate for the repairs. By law, this estimate must be quite accurate. ¦ Preventive maintenance (PM) involves regularly scheduled service on a vehicle to keep it operating efficiently and safely. Professional technicians should stress the importance of PM to their customers. ¦ Engine oil is a clean or refined form of crude oil. It contains many additives, each intended to improve the effectiveness of the oil. ¦ The American Petroleum Institute (API) classifies engine oil according to its ability to meet the engine manufacturers' warranty specifications. ¦ The Society of Automotive Engineers (SAE) has established an oil viscosity classification system that has a numeric rating in which the higher viscosity, or heavier weight oils, receives the higher numbers. ¦ Changing the engine's oil and filter should be done on a regular basis. ¦ Whenever the engine's oil is changed, a thorough inspection of the cooling systems should be done. ¦ Normally, the recommended mixture for engine coolant is a 50/50 solution of water and antifreeze/coolant. ¦ V-belts and V-ribbed (serpentine) belts are used to drive water pumps, power steering pumps, air conditioning compressors, generators, and emission control pumps. ¦ If a belt does not have the proper tension, it may produce squealing and chirping noises; allow the belt to roll off a pulley; or slip, which reduces the power that drives the component. ¦ Excessive belt tension may put unwanted forces on the pulleys and the shafts they are attached to, leading to noise, belt breakage, glazing, and dam age to the bearings and bushings in water pumps, generators, and power steering pumps. ¦ The air filter should be periodically checked for excessive dirt or blockage and a replacement filter should be the same size and shape as the original. ¦ The battery is the main source of electrical energy for the vehicle. It’s very important that it’s checked on a regular basis. ¦ If the battery or any of the associated parts are dirty or corroded, remove the battery and clean them. ¦ The condition of the automatic transmission fluid (ATF) should be checked while checking the fluid level. ¦ Normally the fluid used in power-steering systems is ATF. Check the service manual for the proper fluid type before adding fluid. ¦ Check the level of the brake fluid and make sure the fluid is the correct type and is fresh and clean. ¦ There are basically four types of brake fluids: DOT 3, DOT 4, DOT 5, and DOT 5.1. Most automakers specify DOT 3 fluid for their vehicles. ¦ Check the windshield wipers for signs of dullness, tears, and hardness. Also check the spring on the wiper arm. ¦ The vehicle's tires should be checked for damage and wear as well as for proper inflation. ¦ To equalize tire wear, most car and tire manufacturers recommend that the tires be rotated after a specified mileage interval. ¦ Several parts of a vehicle may need periodic lubrication; always use the correct type of grease when doing this. ¦ Some PM procedures are unique to hybrid vehicles; always follow the recommendations of the manufacturer. ¦ When servicing a hybrid vehicle, always respect its high-voltage system. EXAM 1. Describe the information found in a VIN. 2. Technician A stresses the need to follow the manufacturer's recommendations for preventive maintenance to his customers. Technician B says that the proper PM service intervals depends on the customer's driving habits and typical driving conditions. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 3. Technician A says that tires should have a tread depth of at least 1/16 of an inch. Technician B says that tires have a tread wear indicator built into them. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 4. When working on a hybrid electric vehicle, which of the following statements does not reflect things you should be aware of ? a. The engine will normally shut down and restart when stopped. b. The engine may start at any time when its control system senses that the battery needs to be recharged. c. The system may decide to power the vehicle, while it’s parked, by the engine anytime the load is great. d. Make sure the "READY" lamp in the instrument cluster is off; this lets you know the sys tem is off. 5. True or False? Legally, an RO protects the shop and the customer. 6. While examining the color of an engine's cool ant: Technician A says that because it’s orange, the cooling system should be flushed and new coolant put into the system. Technician B says that the coolant looks rusty and the cooling sys tem should be flushed and new coolant put into the system. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 7. While checking the condition of a vehicle's ATF: Technician A says that if the fluid has a dark brownish or blackish color, the fluid has been overheated. Technician B says that a milky color indicates that engine coolant has been leaking into the transmission's cooler in the radiator. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 8. Technician A says that if a drive belt does not have the proper tension, it may produce squealing and chirping noises. Technician B says that excessive tension may cause noise, belt break age, and glazing. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 9. List five things that engine oil is formulated to do. 10. Technician A says that the rubber diaphragm attached to the inside of the master cylinder caps is designed to stop dirt from entering the reservoir. Technician B says that the rubber diaphragm is designed to stop air from entering the reservoir. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 11. Why should you wipe off the outside of a zerk fit ting before injecting grease into it? 12. True or False? All engine coolants contain some phosphates, which make them unfriendly to the environment. 13. List at least five things that should be checked while inspecting a vehicle's battery. 14. True or False? If brake fluid is dark or brown colored, the system must be flushed and the fluid replaced. 15. Which of the following statements about drive belt slippage is not true? a. Excessive heat normally comes from slippage. b. As a V-belt slips, it begins to ride deeper in the pulley groove. c. Slippage can be caused by improper belt tension or oily conditions. d. When there is slippage, heat travels through the drive pulley and down the shaft to the support bearing of the component it’s driving. 16. True or False? ATF labeled as "Multivehicle ATF" can safely be used in all automatic transmissions. 17. Which of the following statements about an oil's viscosity is not true? a. The ability of oil to flow is its viscosity. b. Viscosity is affected by temperature; hot oil flows faster than cold oil. Oil flow is important to the life of an engine. c. In the API system of oil viscosity classification, the lighter oils receive a higher number. d. Heavyweight oils are best suited for use in high-temperature regions. Low-weight oils work best in low temperature operations. 18. While discussing the readings on a built-in hydrometer in a battery: Technician A says that the green dot means the battery is charged enough for testing. Technician B says that the red dot means the battery is completely discharged and must be replaced. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 19. Which of the following is not a true statement about a mechanic's lien? a. This lien states that the shop may gain possession of the vehicle if the customer does not pay for the agreed-upon services. b. The right to impose a mechanic's lien can be exercised by a shop within 30 days after the services have been completed. c. In most cases, the shop's right to impose a lien on the vehicle being serviced must be acknowledged by the customer prior to beginning any services to the vehicle. d. This clause ensures that the shop will receive some compensation for the work performed, whether or not the customer pays the bill. 20. True or False? An oil with the classification of 5W-30 has the viscosity of both a 10- and 30-weight oil. The 5W means the oil has a viscosity of 5 when warm and a 30 rating when it’s cold. 21. While discussing the effects of over-torquing wheel lugs: Technician A says that this can cause the threads of the lugs and/or studs to distort. Technician B says that this is the most common cause of disc brake rotor distortion. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 22. The most commonly used brake fluid in domes tic vehicles is: a. DOT 2 c. DOT 4 b. DOT 3 d. DOT 5 23. Which of the following greases are best suited for lubricating automotive wheel bearings? a. LA c. GA b. LB d. GC 24. While discussing the special preventive maintenance items for a hybrid vehicle: Technician A says that special coolants are required in most hybrids because the coolant not only cools the engine, but also the inverter assembly. Technician B says that the battery cooling system may have a filter in the ductwork from the outside of the vehicle to the battery box and that this filter needs to be periodically changed. Who is correct? a. Technician A c. Both A and B b. Technician B d. Neither A nor B 25. How does a technician determine the proper inflation of a vehicle's tires? Next: Automotive Engine Designs and Diagnosis Prev.: Basic Services Home Article Index top of page |
