Engine Controls - 6.6L (Lly) (Introduction): Other Chevrolet Silverado 3500

Temperature vs Resistance

Temperature vs Resistance

Altitude vs Barometric Pressure

Altitude vs Barometric Pressure

What Fuel to Use in the United States

In the United States, for best results use Number 2-D diesel fuel year-round, above and below freezing conditions, as oil companies blend Number 2-D fuel to address climate differences. Number 1-D diesel fuel may be used in very cold temperatures when the temperature stays below -18°C (0°F). However, the fuel will produce a power and fuel economy loss. The use of Number 1-D diesel fuel in warm or hot climates may result in stalling, poor starting when the engine is hot and may damage the fuel injection system.

Diesel fuel may foam when filling the tank. This can cause the automatic pump nozzle to shut OFF, even though the tank is not full. If this happens, just wait for the foaming to stop and then continue to fill the tank.

What Fuel to Use in Canada

Canadian fuels are blended for seasonal changes. Diesel Type A fuel is blended for better cold weather starting, when it stays below -18°C (0°F). However, the fuel will produce a power and fuel economy loss. The use of Type A diesel fuel in warmer climates may result in stalling, poor starting. Diesel Type B fuel is blended for temperatures above -18°C (0°F). The emission control system requires the use of diesel fuel with low sulfur, 0.05 percent by weight, content. Both low and higher sulfur fuels will be available in Canada. Only low sulfur diesel fuels are available in the United States. Diesel-powered trucks must be refueled only with low sulfur fuel. Use of fuels with higher-sulfur content will affect the function of the emission components and may caused reduced performance, excessive smoke and unpleasant odor.

Fuel Injector Return Flow and Fuel Pressures

The fuel return from the fuel injectors to the tank will vary based on the API value of the fuel. Measure the Fuel API with the Diesel Fuel Quality Tester. For this reason the Fuel System Diagnosis - High Pressure Side values will vary for identifying a fuel injector or fuel pump concern. Use the following tables when referred to by the diagnostic. The first table is to be used during the initial diagnosis to identify the worst fuel injectors. After the fuel injectors that fail the first part of the test are capped off, the return flow from each uncapped fuel injector must be measured again. This is because the fuel system is returning less fuel to the tank, and thus the fuel pressure is higher during the retest. Failure to use the correct table may result in the replacement of good fuel injectors.

Initial Fuel Injector Return Flow Values

Retesting Fuel Injector Return Flow Values

Water in Fuel

Sometimes, water can be pumped into the fuel tank along with diesel fuel. This can happen if the service station does not regularly inspect and clean their fuel tanks, or the fuel gets contaminated for the service stations suppliers.

If water is pumped into the fuel tank, a water in fuel light will illuminate. If the water in fuel light illuminates, the excess water must be drained from the fuel system on the vehicle.

Quick Connect Fitting(s) Service (Metal Collar)

Tools Required

1. J 44581 Fuel Line Disconnect Tool
2. J 43178 Fuel Line Disconnect Tool

Scheme 378

1. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-184144-S12006988322005082200000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-184144-S01033869922005082200000) in Engine Electrical.
2. Remove the fuel fill cap.
3. Remove the retainers from the fuel feed and return pipe quick connect fittings.
4. Using compressed air, blow any dirt or debris from around the fitting.
5. Using the correct end of J 44581 for the size of the fitting. Insert J 44581 into the female connector, then push inward in order to release the locking tabs.
6. If the vehicle is a cab/chassis, it may be necessary to use J 43178 in order to release the quick connect fittings at the sending unit.
7. Pull the connection apart.
8. Use a clean shop towel in order to wipe off the male end. NOTE: If necessary, remove rust or burrs from the fuel pipes with an emery cloth. Use a radial motion with the fuel pipe end in order to prevent damage to the O-ring sealing surface. Use a clean shop towel in order to wipe off the male tube ends. Inspect all the connections for dirt and burrs. Clean or replace the components and assemblies as required.
9. Inspect both ends of the fitting for dirt and burrs. Clean or replace the components as required.

Fuel System Priming

Scheme 379

1. Prior to priming the engine, ensure that the following has been completed: There is fuel in the fuel tank. The fuel filter has been installed and properly tightened. The fuel lines are properly connected. The fuel filter is cool to the touch. Any dirt or debris has been removed from the fuel filter head and vent valve.
2. Open the vent valve by turning the screw counterclockwise several full turns.
3. Operate the priming pump until a small amount of fuel seeps from the vent valve. Allow the pump to return upward between pumps. When fuel is present, the filter is full of fuel and the system should be primed.
4. Close the vent valve.
5. Clean any fuel which accumulated on the fuel filter.
6. Start the engine and allow it to idle for a few minutes.
7. Check the filter for leaks.

Scheme 380

1. Drain the fuel from the fuel filter. Refer to «Water-in-Fuel Draining Procedure»(ref-184140-S06124440952005082200000) .
2. Reposition the fuel hose clamps.
3. Remove the fuel hoses.
4. Disconnect the fuel filter connectors.
5. Unscrew the fuel filter from the fuel filter adapter.
6. Remove the water-in-fuel sensor from the fuel filter.

Tools Required

J 45004 Fuel Tank Siphon Hose

J 45722 Fuel Sender Lock Ring Wrench

Scheme 381

1. Remove the fuel tank. Refer to «Fuel Tank Replacement (Pickup)»(ref-184140-S35717125452005082200000) or «Fuel Tank Replacement (Cab/Chassis - Front)»(ref-184140-S02256317682005082200000) or «Fuel Tank Replacement (Cab/Chassis - Rear)»(ref-184140-S26735587002005082200000) .
2. Disconnect the fuel lines from the sending unit. Refer to «Quick Connect Fitting(s) Service (Metal Collar)»(ref-184140-S14232518412005082200000) or «Quick Connect Fitting(s) Service (Plastic Collar)»(ref-184140-S23553132162005082200000) .
3. Using J 45722 , remove the sending unit lock ring.
4. Remove the sending unit and seal. Discard the seal.
5. Clean the sending unit sealing surfaces.

Fuel System Cleaning

Fungi and other microorganisms can survive and multiply in diesel fuel if water is present. The fungi can be present in any part of the fuel handling system. These fungi grow into long strings and will form into large globules. The growths appear slimy and are usually black, green, or brown. The fungi may grow anywhere in the fuel but are most plentiful where diesel fuel and water meet. As the fuel is agitated, when service station tanks are being filled, fungi are distributed throughout the tank and may be pumped into a vehicle.

Fungi use the fuel as their main energy supply and need only trace amounts of water and minerals. As they grow and multiply, they change fuel into water, sludge, acids, and products of metabolism. The most common symptom is fuel filter plugging; however, various metal components including the fuel sending unit, pipes, fuel injectors, and injection pump can corrode.

If fungi have caused fuel system contamination, use a diesel fuel biocide to sterilize the fuel system. Do not exceed the dosage recommended on the label. Discontinue the use of a biocide when towing a trailer. It is permissible to have biocide in the fuel when starting to tow, but do not add any biocide while towing.

Steam cleaning may be necessary if most of the fungus growth cannot be removed with biocides.

The presence of water or gasoline in diesel fuel may also cause injection pump and nozzle damage.

This procedure checks for the presence of water and gasoline in diesel fuel that may cause injection pump and nozzle damage.

Remove and inspect the fuel filter element.

1. If water, gasoline or fungi/bacteria are not present, end the inspection.
2. If water or fungi/bacteria are present, proceed to Cleaning Water from the Fuel System.
3. If gasoline is present, proceed to Cleaning Gasoline from the Fuel System.

Cleaning Water from the Fuel System

1. Disconnect the negative battery. Refer to «Battery Negative Cable Disconnect/Connect Procedure (Single Battery)»(ref-184144-S12006988322005082200000) or «Battery Negative Cable Disconnect/Connect Procedure (Auxiliary Battery)»(ref-184144-S01033869922005082200000) in Engine Electrical.
2. Remove the sending unit. Refer to «Fuel Sender Assembly Replacement»(ref-184140-S30811292652005082200000) .
3. Inspect the fuel tank and the fuel sender for rust, fungi or bacteria. If there is rust, replace the rusted components.
4. Clean the inside of the fuel tank and the fuel sender with hot water.
5. Use compressed air in order to dry the fuel tank and the fuel sender.
6. Disconnect the ends of the following lines: The fuel filter inlet line (both ends) The transfer pump pressure line and suction line (if applicable) The fuel filter outlet line (both ends) The fuel filter drain The fuel return line (both ends)
7. Inspect each of the pipes and lines.
8. Replace any rusted pipes.
9. Clean the inside of the fuel filter housing.
10. Dry the fuel filter housing with compressed air.
11. Dry the inside of each line with low pressure air.
12. Remove the ignition 1 relay from the underhood relay center.
13. Install a new fuel filter. Refer to «Fuel Filter Replacement»(ref-184140-S03894690872005082200000) .
14. Install the sending unit Refer to «Fuel Sender Assembly Replacement»(ref-184140-S30811292652005082200000) .
15. Add clean diesel fuel to the primary tank until the tank is 1/4 full.
16. Reconnect the following lines: The fuel filter inlet line The fuel filter outlet line The transfer pump pressure and suction (both ends) lines The fuel return line (tank end)
17. Connect the fuel filter drain to a line that flows into a clean metal container.
18. Connect the batteries.
19. Operate the fuel system hand primer at the fuel filter until clean fuel flows from the fuel filter drain into a metal container.
20. Close the fuel filter drain and remove the bleeder hose.
21. Install a hose on the fuel return line near the glow plug relay, and insert other end into a 7.6 liters (2 gallon) metal container.
22. Crank the engine for 30 second time intervals, with 1 minute cool-down periods. Continue until 3.8 liters (1 gallon) of fuel has passed into the container.
23. Connect the fuel return line.
24. Install the ignition 1 relay in the underhood relay center.
25. Start and run the engine.
26. Stop the engine.
27. Clean any fuel spillage from the engine.
28. Fill the fuel tank and add a biocide, if needed.

Cleaning Gasoline from the Fuel System

1. Drain the fuel tank.
2. Fill the fuel tank to 1/4 full.
3. Remove the ignition 1 relay from the underhood relay center.
4. Loosen the fuel filter drain and connect the filter to a hose that flows into a metal container.
5. Operate the fuel system hand primer at the fuel filter until clean fuel flows from the fuel filter drain into the metal container.
6. Hand tighten the fuel filter drain and disconnect the hose.
7. Install a hose on the fuel return line near the glow plug relay, and insert the other end into a 7.6 liters (2 gallon) metal container.
8. Crank the engine for 30 second time intervals, with 1 minute cool-down periods. Continue until 3.8 liters (1 gallon) of fuel has passed into the container.
9. Reconnect the fuel return line.
10. Install the ignition 1 relay into the underhood relay center.
11. Attempt to start and run the engine for 15 minutes. If the engine does not start, operate the hand primer for 30 strokes, or until firm.
12. Stop the engine.
13. Clean any fuel spillage from the engine.
14. Clear the engine of any diagnostic trouble codes (DTCs).

Fuel Feed and Fuel Return Pipe Purge Procedure

1. Pump the primer located on top of the fuel filter 30 times or until stiff.
2. Attempt to start and run the engine. If the engine does not start, repeat step 1.
3. Allow to run for 5 minutes at idle.
4. Check for fuel leaks.
5. Clear all engine diagnostic trouble codes (DTCs).

Preparing The Fuel Injection Pump

1. Hold the fuel pump by the drive gear in a vice with copper jaw liners.
2. Loosen the gear nut until the nut is even with the end of the gear shaft.
3. Remove the gear from the tapered shaft of the injection pump.
4. Separate the injection pump and adapter by removing the 3 bolts and spacers.
5. Inspect the O-ring for damage on the pump adapter and replace, if necessary. Lubricate the O-ring with clean engine oil.
6. Clean all mating surfaces.
7. Install the adapter on the pump. NOTE: Refer to «Fastener Notice»(ref-184123-S11449185592005082200000) in Cautions and Notices.
8. Install the 3 bolts and spacers. Tighten: Tighten the bolts to 20 N.m (15 lb ft).
9. Install the gear and nut. Tighten: Tighten nut to 70 N.m (52 lb ft).

J-46594 Fuel Injector Remover

J-46594 Fuel Injector Remover

Exhaust Gas Recirculation (EGR) System Cleaning

1. Remove the exhaust gas recirculation (EGR) cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(ref-184140-S29460381972005082200000) .
2. Depress the pintle several times using a pencil eraser or other suitable soft instrument. The pintle should move in and out smoothly. Replace the valve if the valve exhibits tendencies to stick.
3. Try to rotate the EGR valve electrical connector housing. Repeat for the coil housing. Replace the valve if the valve exhibits any looseness. Inspect the EGR valve pintle and seat for deposits. Use a cloth or other suitable soft device to remove the deposits. Remove all loose particles. Replace the valve if the deposits are such that the pintle to base interface cannot be cleaned adequately to allow the pintle to seal against the seat. Damage to the powdered metal EGR valve base occurs if cleaned with solvents, sharp tools, wire brush or wheel, or sand blasting. Cleaning by these methods is not recommended.
4. Clean the passages with a wire brush. Remove all loose particles.
5. Install the EGR cooler tube. Refer to «Exhaust Gas Recirculation (EGR) Valve Cooler Tube Replacement»(ref-184140-S29460381972005082200000) .

Control Module Communications

The control module system has a computer, the engine control module (ECM), to control fuel delivery, timing, and some emission control systems. The control module system monitors a number of engine and vehicle functions and controls the following operations through the fuel injection control module (FICM)

1. Fuel rail pressure
2. Fuel injector
3. Fuel injector pulse width

The diesel ECM, located in the engine compartment, is the control center of the control module system. The engine control module used on the electronic fuel injected 6.6L diesel is referred to as a ECM.

The ECM constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM performs the diagnostic function of the system. The ECM can recognize operational problems, alert the driver through the MIL - Service Engine Soon, and store one or more diagnostic trouble codes (DTCs) which identify the problem areas to aid the technician in making repairs. See the specific diagnosis procedure for more information.

Aftermarket (Add-On) Electrical And Vacuum Equipment

Any equipment installed on a vehicle after leaving the factory that connects to the electrical or vacuum systems of the vehicle defines aftermarket (Add-On) electrical and vacuum equipment. The vehicle design makes no allowances for this type of equipment.

Note. Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to vehicle components or systems.

Note. Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to prevent damage to the vehicle.

The add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include any equipment which is not connected to the electrical system of the vehicle such as portable telephones and radios. Therefore, the first step in diagnosing any powertrain problem is to eliminate all of the aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, diagnose the problem in the normal manner.

Engine Controls Information

The driveability and emissions information describes the function and operation of the control module. The emphasis is placed on the diagnosis and repair of problems related to the system.

Engine Components, Wiring Diagrams, and Diagnostic Trouble Code (DTC) tables

1. The Component Locations
2. The Wiring Diagrams
3. The Control Module Terminal End View and Terminal Definitions
4. The Diagnostic System Check - Engine Controls
5. The Diagnostic Trouble Code (DTC) tables

The Component System includes the following items

1. The component and circuit description
2. The On-vehicle service for each subsystem
3. The Functional checks with the diagnostic tables
4. How To Use Electrical Systems Diagnostic Information

The DTCs also contain the diagnostic support information containing the circuit or the system information, and helpful diagnostic information.

Connectors and Terminals

In order to prevent shorting between opposite terminals, use care when probing a connector and when replacing terminals. Damage to the components could result.

Always use jumper wires between connectors for circuit checking.

Never probe through the Weather-Pack seals.

The J 35616 Connector Test Adapter Kit, or the equivalent, contains an assortment of flexible connectors used in order to probe the terminals during the diagnosis. The fuse remover and the BT-8616 Test Tool, or the equivalent, is used for removing a fuse and to adapt the fuse holder to a meter for diagnosis.

Open circuits are often difficult to locate by sight because oxidation or terminal misalignment are hidden by the connectors. Merely wiggling a connector on a sensor or in the wiring harness may temporarily correct the open circuit. Oxidized or loose connections may cause intermittent problems.

Be certain the type of connector and terminal before making any connector or terminal repair. Weather-Pack and Com-Pack III terminals look similar, but are serviced differently.

Scheme 382

The accelerator pedal position (APP) system along with the vehicle electronics and components is used to calculate and control the amount of acceleration and deceleration via fuel injector control. This eliminates the need for a mechanical cable attachment from the accelerator pedal to a throttle body.

The APP system includes, but is not limited to, the following components

1. The accelerator pedal position (APP) sensor assembly
2. The engine control module (ECM)

Accelerator Pedal Position (APP) Sensor

The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of 3 individual sensors within one housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to interface the accelerator pedal sensor assembly with the ECM. Each sensor has a unique functionality to determine pedal position. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the person driving the vehicle. The APP sensor 1 voltage should increase as the accelerator pedal is depressed, from below 1.0 volt at 0 pedal travel to above 2 volts at 100 percent pedal travel. APP sensor 2 voltage should decrease from above 4 volts at 0 pedal travel to below 3.0 volts at 100 percent pedal travel. APP sensor 3 voltage should decrease from above 3.8 volts at 0 percent pedal travel to below 3.3 volts at 100 percent pedal travel.

Fuel Level Sensor

The fuel level sensor consists of a float, a wire float arm, and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the amount of fuel in the fuel tank. The engine control module (ECM) sends the fuel level information via the class 2 circuit to the instrument panel cluster (IPC). This information is used for the instrument panel (I/P) fuel gage and the low fuel warning indicator, if applicable. The ECM also monitors the fuel level input for various diagnostics.

Fuel Strainer

The fuel strainer attaches to the lower end of the fuel sender. The fuel strainer is made of woven plastic. The functions of the fuel strainer are to filter contaminants and to wick fuel. The fuel strainer is self-cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment.

Scheme 383

On vehicles equipped with dual fuel tanks, an electric fuel pump is located on the left frame rail. This fuel pump is powered by the fuel pump relay that is controlled by the engine control module (ECM). Fuel is transferred from the auxiliary fuel tank to the primary fuel tank in order to ensure all of the usable fuel volume is available to the fuel injection pump.

Scheme 384

The fuel injection pump is a mechanical high pressure pump. The fuel injection pump is located below the intake manifold. Fuel is pumped to the fuel rails at a specified pressure. Fuel pressure is regulated by a valve on the inlet of the fuel pump, controlled by the engine control module (ECM). Excess fuel from the fuel injection pump returns to the fuel tank through the fuel return pipe and a fuel cooler.

Fuel Filter

The fuel filter is located on the rocker cover. The paper filter element traps particles in the fuel that may damage the fuel injection system.

Fuel Feed and Return Pipes

The fuel feed pipe carries fuel from the fuel tank to the fuel injector control module. The fuel return pipe carries fuel from the fuel rail assemblies back to the fuel tank. The fuel pipes consist of 2 sections

1. The rear fuel pipe assemblies are located from the top of the fuel tank to the chassis fuel pipes. The rear fuel pipes are constructed of steel with sections of rubber hose covered with braiding.
2. The chassis fuel pipes are located under the vehicle and connect the rear fuel pipes to the fuel rail pipes. These pipes are constructed of steel with sections of rubber hose covered with braiding.

Quick-Connect Fittings

Quick-connect fittings provide a simplified means of installing and connecting fuel system components. The fittings consist of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the fittings together.

Fuel Pipe O-Rings

O-rings seal the connections in the fuel system. Fuel system O-ring seals are made of special material. Service the O-ring seals with the correct service part.

Scheme 385

The left and right fuel rail assemblies attach to the cylinder heads. The fuel rail assemblies distribute pressurized fuel to the fuel injectors through the fuel lines.

The fuel rail assemblies consists of the following components

1. The fuel rail pressure sensor in the right fuel rail
2. The fuel pressure relief valve in the left fuel rail

The fuel rail pressure sensor gives the engine control module (ECM) an indication of fuel pressure. The ECM uses this information to regulate fuel pressure, by commanding the fuel pressure regulator open or closed on the inlet of the fuel injection pump.

The fuel pressure relief valve opens only to prevent excessive pressure in the event of a malfunction. Fuel from the fuel pressure relief valve is returned to the fuel tank.

Scheme 386

A fuel injector is a solenoid device, controlled by the fuel injection control module (FICM), that meters pressurized fuel to a single engine cylinder. The engine control module (ECM) energizes the low-impedance injector solenoid to open a normally closed valve. Fuel pressure is released from above the fuel injector pintle, and is returned to the fuel tank through the fuel return lines. The difference in fuel pressure above and below the pintle causes the pintle to open. Fuel from the fuel injector tip is sprayed directly into the combustion chamber on the compression stroke of the engine.

Fuel System Cooler

The fuel system cooler (1) is located in front of the primary fuel tank. The fuel system cooler cools the fuel before it is returned to the fuel tank.

High Idle System

The diesel engine has a high idle system to improve the warm-up time of the engine in cold weather conditions. This system allows the engine control module (ECM) to increase the idle speed above the normal calibrated value. The ECM increases the idle speed using the following adjustments

1. The fuel injection timing is changed.
2. The fuel injection quantity is changed.
3. The turbocharger vane position is commanded closed. the vane position will be farther closed than any other normal operating condition.

The instrument panel will indicate the high idle system is active one of two ways

1. The driver information center (DIC) will indicate an active high idle system on light duty trucks.
2. An indicator lamp will flash on medium duty trucks.

High Idle Speed Enable and Disable

To enable or disable the high idle system perform the following procedure

1. Turn the ignition ON, with the engine OFF.
2. Depress the accelerator pedal to the floor and hold down.
3. While the accelerator pedal is depressed, depress the brake pedal 3 times in less than 8 seconds.
4. Release the accelerator pedal.
5. Start the engine.

When the procedure is followed the engine idle speed will slowly increased to the calibrated high idle speed. This is 1200 RPM for light duty, and 1500 RPM for medium duty trucks.

The idle speed will return to normal if any of the following conditions occur

1. There is brake, clutch, or throttle input from the driver.
2. The automatic transmission is shifted out of Park or Neutral.
3. The air temperature is more than 0°C (32°F).
4. The engine coolant temperature (ECT) is more than 68°C (154°F)
5. The vehicle speed exceeds 0 km/h (0 mph).

The high idle system will reactivate automatically when the following conditions occur

1. The engine has been idling for more than 30 seconds.
2. The transmission is placed in Park or Neutral.
3. the vehicle speed is 0 km/h (0 mph).
4. The ambient air temperature is less than 0°C (32°F).
5. The ECT is less than 68°C (154°F)
6. The brake, clutch and throttle pedals are not depressed.

Glow Plugs

The glow plugs are 4.7-volt heaters in each of the cylinders that turn ON, then pulse-width modulated when the ignition switch is turned to the RUN position prior to starting the engine. They remain pulsing a short time after starting, then they are turned OFF.

A Wait to Start lamp on the instrument panel provides information on engine starting conditions. The Wait to Start lamp will not illuminate during post-start glow plug operation.

Glow Plug/Controller

The glow plug controller is a solid state device which operates the glow plugs. The glow plug controller is connected to the following circuits

1. The fuel heater ignition 1 voltage circuit
2. The battery voltage circuit
3. The CAN communication circuit located between the engine control module (ECM) and the glow plug controller
4. The engine ground circuit
5. The glow plug supply voltage circuits located between the glow plug controller and the glow plugs.

The glow plug diagnostic circuits are directly monitored individually by using a separate transistor to control current to each glow plug. Individual diagnosis is thus possible for every glow plug.

EGR Valve Control Enabling Conditions.

Exhaust gas recirculation (EGR) valve control will only be enabled during idle and cruising conditions while the following conditions are met

1. The intake air temperature (IAT) is more than 5.25°C (41.5°F). EGR valve control will remain enabled until the IAT is less than 0°C (32°F) and will not enable again until the IAT is more than 5.25°C (41.5°F).
2. The engine coolant temperature (ECT) is between 60-96.75°C (140-206.15°F). EGR valve control will remain enabled until the ECT is less than 57°C (134.6°F) or more than 99.75°C (211.55°F) and will not enable again until the ECT is between 60-96.75°C (140-206.15°F).
3. The barometric pressure (BARO) is more than 74 kPa. EGR valve control will remain enabled until the BARO is less than 72 kPa and will not enable again until 74 kPa.

Turbocharger Vane Position Control Solenoid Valve

The vane position control solenoid valve (2) works in conjunction with oil pressure to control the turbocharger vanes. The solenoid valve uses 2 circuits; a control circuit and a low reference circuit. The engine control module (ECM) uses a pulse width modulation on the HI control circuit to control the solenoid valve. The ECM will control the solenoid valve to allow the engine oil pressure (EOP) to move a piston (6). This piston rotates the unison ring, thus controlling the engine boost dependant upon engine load.

Turbocharger Vane Position Sensor

The vane position sensor (1) uses 3 circuits: a 5-volt reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) provides the sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Movement of the sensor from the open vane position to the closed vane position provides the ECM with a signal voltage through the position sensor signal circuit that ranges from 1 volt with the turbocharger vanes open to 3.5 volts with the turbocharger vanes completely closed.

Engine Control Module (ECM)

The engine control module (ECM) controls all turbocharger control functions. The ECM monitors information from various sensor inputs that include the following

1. The accelerator pedal position (APP) sensor
2. The engine coolant temperature (ECT) sensor
3. The mass airflow (MAF) sensor
4. The intake air temperature (IAT) sensor
5. The vehicle speed sensor (VSS)
6. The transmission gear position or range information sensors
7. The boost pressure sensor