DANGER: High Voltage!

Will your technicians be ready when the first hybrid rolls into your shop?

Inspecting and Rotating Tires and Brakes: Every 5,000 to 6,000 miles, not only do the tires have to be rotated, but the rotors need to be inspected. Rusting is a common problem with hybrids' rotors, because of they are not used as often due to regenerative brakes.

ANNUAL MX (EVERY 12,000-15,000 MILES)

Throttle Body Service: If you are dealing with a Toyota Prius or any hybrid with an electrical throttle, maintenance of the throttle body every 12,500 miles is especially important.

HVAC System-Cabin Filter: On Ford hybrids, there is a rear filter for the battery HVAC behind the rear seats that needs to be replaced.

Battery Starting/Charging Test: During the winter, do a State of Charge (SOC) test on the 12V and HV batteries with a scan tool. Also, on Toyotas, don't forget to purchase a special battery charger for the glass-mat 12 volt battery. The maximum charging amperage is 3.5.

A/C System Service: During the summer, hybrids will require run of the mill maintenance. But not so fast! Hybrid A/C systems are a different beast than non-hybrids. Toyota hybrids (2005 model year and up and Hondas 2006 and up) have electric compressors. In some cases, this eliminates the need for an A/C clutch or belt, and full A/C operation even with the ICE off is now possible.

Many Honda, Ford, and GM hybrids have dual scroll compressors. Such a compressor is in fact two compressors in one: one belt driven off the engine and one electric. They can work both independently or combined, but when combined the autostop feature of the hybrid is deactivated.

The preceding means that if there is a compressor problem with a hybrid, you are going to have to look at the high voltage circuit. The compressor, whether it is fully electric or dual scroll (in autostop mode), can be inoperative because of an electrical problem. As the old adage goes, a technician has to wear many hats, and this is especially true with hybrids.

Another difference be- tween hybrid and non-hybrid A/C is that there is no single universal PAG oil/lubricant. Hybrids use different kinds of oils, mostly POE (polyol ester) oils, and no dye. If PAG oil or a PAG dye are put in, severe damage and possible high voltage problems will exist, and this can be DANGEROUS.

A/C maintenance is not something optional on hybrids. Let your customers know if they own a Ford/Mercury hybrid that the A/C system actually cools the HV battery and the HV battery is the most expensive piece of equipment in the vehicle! So, make sure the A/C is fully functional.

Computer Systems Check: Check the hybrid controllers, because not all DTCs turn on the dash lights.

Coolant Service: Note that some hybrids have dual systems, one for the engine and the other for the inverter. Furthermore, this means that many of the hybrids require special coolants. In order to service such systems, you should consult the manufacturer's recommendations and use the correct coolant.

Spark Plugs: Be sure to use the OEM recommended plugs and apply a small amount of anti-seize to the plugs every 30,000 miles.

Brake Fluid: Flush or bleed the hydraulic brake system. We should remind our customers that proper brake service for hybrids is essential for their safety.

Bleeding the brakes on a hybrid requires a special precaution: many hybrids' brakes have a self-test. As long as the 12V and HV batteries are connected or "SBSM" (Safe Brake Service Mode) is not activated on Ford Escapes, you run the risk of having the brakes pressurize without you commanding them to.

You will need to deactivate and depressurize the brakes before working on the system. Consult the manufacturer's information before work on any Teves brake system.


Unlike a normal repair facility, you have a vested interest in your hybrid vehicles. You already made the investment in purchasing them, so it is wise to take care of them right. To get the most MPG from hybrids, implementing a driver/operator training course may be a good idea. Most importantly, the proper maintenance of hybrid vehicles increases their fuel economy and their longevity. So, invest in educating your techs and operators, and you should be fine!

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