GM Service Manual Online
For 1990-2009 cars only

The diesel engine starts differently than a gasoline engine. The vehicle will only start in the P (Park) or the N (Neutral) position.

Move the shift lever to P (Park) or N (Neutral). To restart the engine when the vehicle is already moving, use N (Neutral) 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 the Engine

  1. Turn the ignition key to ON/RUN.
  2. Observe the wait to start light. See Wait to Start Light. This light may not come on if the engine is warm.

  3. 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.
  4. The 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.

  5. If the engine does not start after 15 seconds of cranking, turn the ignition switch to LOCK/OFF. Wait one minute for the starter to cool, then try the same steps again.

If you are trying to start the engine after you have run out of fuel, follow the steps in Running Out of Fuel.

When the engine is cold, let it run for a few minutes before you move the vehicle. This lets oil pressure build up. The 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 with cold weather starting.

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 elevations (over 7,000 ft. or 2 135 m), you may use the 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 the Diesel Engine Will Not Start

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

If the vehicle is not out of fuel, and the engine will not start, do this:

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

If the light does not go off, wait a few seconds, then try starting the engine again. See your dealer/retailer as soon as you can for a starting system check.

If the light comes on and then goes off and you know the batteries are charged, but the engine still will not start, the vehicle needs service.

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

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

Be sure you have the right oil for the engine, and that you have changed the oil at the proper times. If you use the wrong oil, the 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, the 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 engine idle speed from base idle to 1050 rpms for pickup models or 1200 rpms for van models 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.

This feature can be turned on or off using the DIC steering wheel control buttons. If the vehicle is not equipped with the DIC steering wheel control buttons, do the following to turn this feature on or off:

  1. Turn the ignition to ON/RUN, with the vehicle off.
  2. Press the accelerator pedal to the floor and hold while quickly pressing the brake pedal three times in less than eight seconds.
  3. 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 P (Park) or N (Neutral).
    • 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.

Fast Idle Control

This system can be used to increase the engine idle speed.

Fast Idle control will be enabled when the following conditions are met:

    • The park brake is set.
    • The transmission is in P (Park) or N (Neutral).
    • The vehicle speed is about 0 mph (0 km/h).
    • The cruise control is in the On position. See "Cruise Control" in the Index of the vehicle owner manual.
    • The cruise control Set switch is pressed and released for Preset Fast Idle Speed (1200 rpm).

Fast Idle control will be disabled when one or more of the following conditions occur:

    • The cruise control is in the Off position.
    • The cruise control Set switch is pressed and released. See "Cruise Control" in the Index of the vehicle owner manual.
    • The cruise control Cancel switch is pressed.
    • The brake pedal is pressed.
    • The transmission is shifted out of P (Park) or N (Neutral).
    • The park brake is released.
    • The vehicle speed is not 0 mph (0 km/h).

When Fast Idle is active, a FAST IDLE ON message will be displayed in Driver Information Center (DIC). See DIC Warnings and Messages.