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Starting and Operating Your Vehicle | Description and Operation | Document ID: 170615

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2007 GMC Truck Sierra Classic - 4WD | DURAMAX Diesel Engine | Features and Controls | Starting and Operating Your Vehicle | Description and Operation | Document ID: 1706150


Starting the Diesel Engine

Your diesel engine starts differently than a gasoline engine. As a safety feature, your vehicle will only start in the PARK (P) or the NEUTRAL (N) position.

Move your shift lever to PARK (P) or NEUTRAL (N). To restart when you're already moving, use NEUTRAL (N) only.

Notice: Do not try to shift to P (Park) if the vehicle is moving. If you do, you could damage the transmission. Shift to P (Park) only when the vehicle is stopped.

Starting Your Engine

Turn your ignition key to RUN. Observe the wait to start light. See Wait to Start Light . This light may not come on if the engine is hot.

As soon as the wait to start light goes off, immediately turn the ignition key to START. When the engine starts, let go of the key. Your engine has a fast warm-up glow plug system. The wait to start light will illuminate for a much shorter time than most diesel engines, due to the rapid heating of the glow plug system.

Notice: If the wait-to-start light stays on after starting the vehicle, the vehicle may not run properly. Have the vehicle serviced right away.

If the engine does not start after 15 seconds of cranking, turn the ignition key to LOCK. Wait one minute for the starter to cool, then try the same steps again.
If you're trying to start your engine after you've run out of fuel, follow the steps in Running Out of Fuel .

When your engine is cold, let it run for a few minutes before you move your vehicle. This lets oil pressure build up. Your engine will sound louder when it's cold.

Notice: If you are not in an idling vehicle and the engine overheats, you would not be there to see the overheated engine indication. This could damage the vehicle. Do not let the engine run when you are not in the vehicle.

Cold Weather Starting (Diesel Engine)

The following tips will help you get good starting in cold weather.

Use the recommended engine oil when the outside temperature drops below freezing. See Engine Oil . When the outside temperature drops below 0° F (-18°C), use of the engine coolant heater is recommended.

If you experience longer cranking times, notice an unusual amount of exhaust smoke or are at higher altitudes (over 7,000 ft. or 2 135 m), you may use your engine coolant heater. See Engine Coolant Heater .

See Diesel Fuel Requirements and Fuel System for information on what fuel to use in cold weather.

If Your Diesel Engine Won't Start

If you've run out of fuel, look at Running Out of Fuel . See Diesel Fuel Requirements and Fuel System .

If you're not out of fuel, and your engine won't start, do this:

Turn your ignition key to RUN. Immediately after the wait to start light goes off, turn the ignition key to START.

If the light doesn't go off, wait a few seconds, then try starting your engine again. See your dealer as soon as you can for a starting system check.

If the light comes on and then goes off and you know your batteries are charged, but your engine still won't start, your vehicle needs service.

If the light does not come on when the engine is cold, your vehicle needs service.

If your batteries don't have enough charge to start your engine, see "Battery" in the owner's manual Index.

Be sure you have the right oil for your engine, and that you've changed the oil at the proper times. If you use the wrong oil, your engine may be harder to start.

Be sure you are using the proper fuel for existing weather conditions. See Diesel Fuel Requirements and Fuel System .

If the engine starts, runs a short time, then stops, your vehicle needs service.

Caution: Do not use gasoline or starting aids, such as ether, in the air intake. They could damage the engine. There could also be a fire, which could cause serious personal injury.

Elevated Idle

The engine has a cold temperature high idle feature which elevates the engines idle speed from 680 to 1200 rpms when outside temperatures are below 32°F (0°C), and the engine coolant temperature is below 150°F (65°C.) This feature enhances heater performance by raising the engine coolant temperature faster.

For pickup models, this feature can be turned off and on using the DIC steering wheel control buttons. If your vehicle is not equipped with the DIC steering wheel control buttons, do the following to turn on this feature:

Turn the ignition to RUN, with the vehicle off.
Press the accelerator pedal to the floor and hold while quickly pressing the brake pedal three times in less than eight seconds.
Release the accelerator pedal and start the engine.
When the engine is started, it will slowly ramp up to the high idle speed after a delay of a few seconds up to approximately two minutes. For this method to work properly there must be no throttle or brake pedal faults.

The engine idle speed will return to normal once the following conditions are met:

• Once engine coolant temperature reaches 150°F (65°C).

• Air intake temperature reaches 32°F (0°C).

The high idle speed will be temporarily interrupted and the engine speed will return to normal if any of the following conditions occur:

• The brake pedal is applied.

• The accelerator pedal is pressed.

• The transmission is shifted out of PARK (P) or NEUTRAL (N).

• Vehicle speed is detected.

Once these inputs are removed, the engine idle speed will slowly ramp back up to high idle after the normal delay, if the conditions for engine coolant temperature and air intake temperature are still met.

Manual High Idle System (Van Models Only)

If your vehicle has this feature, the manual high idle switch is located on the instrument panel.

This system can be used to increase your engine idle speed whenever the following conditions are met:

• The brake pedal is not pressed.

• The vehicle speed is below about 5 mph (8 km/h).

• The transmission is in NEUTRAL (N) or PARK (P).

The manual high idle feature is activated by pressing the switch on the instrument panel. When the switch is pressed again, or any of the previous conditions are not met, manual high idle will be deactivated. The manual high idle has been preset at the factory. Your dealer may change the setting to fit your needs.

© 2010 General Motors. All rights reserved.
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