In addition to the regular cooling system, the vehicle also has a cooling system for the DMCM system. This system is serviced differently than the vehicle's main cooling system. The DMCM cooling system includes the DMCM coolant surge tank, DMCM surge tank pressure cap, DMCM cooling pumps, hybrid cooling radiator and the Drive Motor/Generator Control Module (DMCM). The DMCM cooling system uses a 50/50 pre-mixed DEX-COOL™ coolant and deionized water available at your dealer/retailer. See "Engine Coolant" and "Cooling System" in the owner manual for more information.

When you decide it is safe to lift the hood, here is what you will see:

1. Drive Motor/Generator Control Module (DMCM)

2. Engine Coolant Surge Tank Pressure Cap

3. DMCM Coolant Surge Tank/Engine Coolant Surge Tank

4. DMCM Cooling Hoses (Out of View)

5. DMCM Coolant Tank Pressure Cap

If the coolant inside the DMCM coolant surge tank is boiling, do not do anything else until it cools down.

The coolant level should be at or above the FULL COLD mark with the vehicle parked on a level surface. If it is not, there might be a leak at the DMCM cooler core, DMCM pressure cap, DMCM cooler hoses, DMCM cooling pump or somewhere else in the DMCM cooling system.

Notice: Running the engine when there is a leak in the hybrid cooling system can cause the hybrid cooling system to lose all coolant and can damage the system. Get any leak fixed before you drive the vehicle or run the engine.

If no problem has been found yet, check to see if coolant is visible in the DMCM coolant surge tank. If coolant is visible, add pre-mixed DEX-COOL™ coolant, available at your dealer/retailer, at the DMCM coolant surge tank, but be sure the DMCM cooling system, including the DMCM coolant surge tank pressure cap, is cool before you do it. Use the procedure following.

Caution: Steam and scalding liquids from a hot cooling system can blow out and burn you badly. They are under pressure, and if you turn the coolant surge tank pressure cap -- even a little -- they can come out at high speed. Never turn the cap when the cooling system, including the coolant surge tank pressure cap, is hot. Wait for the cooling system and coolant surge tank pressure cap to cool if you ever have to turn the pressure cap.

Notice: Using coolant other than a pre-mixed DEX-COOL, available at your dealer/retailer, may damage your vehicle. Any repairs would not be covered by your warranty. Always use a pre-mixed DEX-COOL (silicate-free) coolant in your vehicle.

Caution: You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and it will burn if the engine parts are hot enough. Do not spill coolant on a hot engine.

If the DMCM coolant is empty , the vehicle must be serviced by your dealer and a special fill procedure must be followed.

Notice: Attempting to fill the DMCM cooling surge tank yourself when the fluid level is empty can damage your vehicle. Your vehicle must be serviced.

1. Park the vehicle on a level surface and turn the vehicle off. Remove the DMCM coolant surge tank pressure cap when the DMCM cooling system, including the DMCM coolant surge tank pressure cap and DMCM cooling hoses, are no longer hot. Turn the DMCM coolant surge tank pressure cap slowly counterclockwise (left) about one full turn. Wait 30 seconds.



2. Then keep turning the DMCM coolant surge tank pressure cap slowly, and remove it.
3. Add the pre-mixed DEX-COOL™, available at your dealer/retailer, to the DMCM coolant surge tank until the level reaches the FULL COLD mark.
4. Turn the ignition to ON/RUN without starting the engine. The hybrid cooling pumps will run and any trapped air will purge to the surge tank.
5. Add the pre-mixed DEX-COOL™, available at your dealer/retailer, until the coolant level is maintained at the FULL COLD mark. This should take no longer than two minutes of hybrid cooling pump operation.

If the level cannot be kept at the FULL COLD level, your vehicle may need service. See your dealer/retailer.





Then replace the DMCM coolant surge tank pressure cap. Be sure the pressure cap is hand-tight and fully seated.

Notice: Using tap water, cooling system sealers or conditioners in an attempt to stop coolant leaks can damage the DMCM and engine cooling systems. Never use tap water, cooling system sealers or conditioners in your cooling system.