Engine Control System & Fuel System - 3.7l - Introduction (2 of 2) Chevrolet Colorado I

Temperature Versus Resistance

Temperature Versus Resistance

Altitude Versus Barometric Pressure

Altitude Versus Barometric Pressure

Ignition System Specifications

Ignition System Specifications

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Engine Control Module Replacement

Service of the engine control module (ECM) should normally consist of either replacement of the ECM or electrically erasable programmable read only memory (EEPROM) programming. If the diagnostic procedures call for the ECM to be replaced, the ECM should be inspected first to see if the correct part is being used. If the correct part is being used, remove the faulty ECM and install the new service ECM.

Note. Turn the ignition OFF when installing or removing the control module connectors and disconnecting or reconnecting the power to the control module (battery cable, powertrain control module (PCM)/engine control module (ECM)/transaxle control module (TCM) pigtail, control module fuse, jumper cables, etc.) in order to prevent internal control module damage. Control module damage may result when the metal case contacts battery voltage. DO NOT contact the control module metal case with battery voltage when servicing a control module, using battery booster cables, or when charging the vehicle battery. In order to prevent any possible electrostatic discharge damage to the control module, do no touch the connector pins or the soldered components on the circuit board. Remove any debris from around the control module connector surfaces before servicing the control module. Inspect the control module connector gaskets when diagnosing or replacing the control module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the control module. The replacement control module must be programmed.

Removal Procedure

1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
2. Disconnect the ECM harness connectors (2) from the ECM (3).
3. Disengage the ECM bracket mounting tabs, while removing the ECM.

Installation Procedure

1. Install the ECM into the ECM mounting bracket, allowing the tabs to fully engage.
2. Connect the ECM harness connectors (2) to the ECM body (3).
3. If a new ECM is being installed, the ECM must be programmed. Refer to «Control Module References»(/chevrolet/colorado/i-2004-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) .
4. If equipped with a manual transmission, perform the clutch pedal position sensor learn procedure. Refer to «Clutch Pedal Position Sensor Learn»(/chevrolet/colorado/i-2004-2012/remont/manual-trans/#manual-transmission-aisin-ar5__clutch-pedal-position-sensor-learn) .

Crankshaft Position System Variation Learn

1. Install a scan tool.
2. Monitor the ECM for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) for the applicable DTC that set.
3. With a scan tool, select the CKP system variation learn procedure and perform the following: Observe the fuel cut-off for the applicable engine. Block the drive wheels. Set the parking brake. Place the vehicle's transmission in Park or Neutral. Turn the air conditioning (A/C) OFF. Cycle the ignition from OFF to ON. Apply and hold the brake pedal for the duration of the procedure. Start and idle the engine. Accelerate to wide open throttle (WOT). The engine should not accelerate beyond the calibrated fuel cut-off RPM value noted in step 3.1. Release the throttle immediately if the value is exceeded. IMPORTANT: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete. Release the throttle when fuel cut-off occurs.
4. The scan tool displays Learn Status: Learned this Ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, refer to «DTC P0315»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-dtc-p0013-to-dtc-p0365) . If any other DTCs set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) for the applicable DTC that set.
5. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.

Description

The engine control module (ECM) learns the idle position of the throttle plate to ensure the correct idle. The learned airflow values are stored within the ECM. These values are learned to adjust for production variation and will continuously learn during the life of the vehicle to compensate for reduced airflow due to coking. Anytime the throttle body airflow rate changes, for example due to cleaning or replacing, the values must be relearned.

A vehicle that had a heavily coked throttle body that has been cleaned or replaced may take several drive cycles to learn out the coking. To accelerate the process, the scan tool has the ability to reset all learned values back to zero. A new ECM will also have values set to zero.

The idle may be unstable or a DTC may set if the learned values do not match the actual airflow.

Conditions for Running the Throttle Learn Procedure

1. DTCs P0101, P0102, P0103, P0107, P0108, P0111, P0112, P0113, P0506, and P0507 are not set.
2. The engine speed is between 450-4,000 RPM.
3. The manifold absolute pressure (MAP) is greater than 5 kPa.
4. The mass air flow (MAF) is greater than 2 g/s.
5. The ignition 1 voltage is greater than 10 volts.

Throttle Learn

With Scan Tool-Reset

1. Ignition ON, engine OFF. With a scan tool, perform the Idle Learn Reset in Module Setup.
2. Start the engine, monitor the TB Idle Airflow Compensation parameter. The TB Idle Airflow Compensation parameter value should equal 0 percent and the engine should be idling at a normal idle speed. If the engine is not idling normally, proceed with the Learn portion of the diagnostic.
3. Clear the DTCs and return to the diagnostic that referred you here.

Without Scan Tool-Learn

1. The engine speed is between 450-4,000 RPM.
2. The manifold absolute pressure (MAP) is greater than 5 kPa.
3. The mass air flow (MAF) is greater than 2 g/s.
4. The ignition 1 voltage is greater than 10 volts.
5. Start and idle the engine in Park for 3 minutes.
6. With a scan tool, monitor desired and actual RPM.
7. The ECM will start to learn the new idle cells and Desired RPM should start to decrease.
8. Ignition OFF for 60 seconds.
9. Start and idle the engine in Park for 3 minutes.
10. After the 3 minute run time the engine should be idling normal. IMPORTANT: During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn. If the engine idle speed has not been learned the vehicle will need to be driven at speeds above 70 km/h (44 mph) with several decelerations and extended idles.
11. After the drive cycle, the engine should be idling normally. If the engine idle speed has not been learned, turn OFF the ignition for 60 seconds and repeat step 6.
12. Once the engine speed has returned to normal, clear DTCs.

Tools Required

J 45861 ECT Sensor Socket

1. Partially drain the cooling system to a level below the engine coolant temperature (ECT) sensor. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/colorado/i-2004-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-static) or «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/colorado/i-2004-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .
2. Disconnect the engine wiring harness electrical connector (1) from the ECT sensor electrical connector.
3. Remove the ECT sensor electrical connector from the camshaft cover.
4. Using the J 45861 (2) carefully remove the ECT sensor (3) from the cylinder head.

Note. Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.

Note. Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.

1. If installing the original sensor or a NEW sensor without sealant, apply thread sealer GM P/N 12346004 (Canadian P/N 10953480) or equivalent.
2. Thread the ECT sensor into the cylinder head by hand.
3. Using the J 45861 (2) tighten the ECT sensor (3). Tighten: Tighten the sensor to 14 N.m (10 lb ft).
4. Install the ECT sensor electrical connector to the camshaft cover.
5. Connect the engine wiring harness electrical connector (1) to the ECT sensor electrical connector.
6. Refill the cooling system. Refer to «Cooling System Draining and Filling (Static Fill)»(/chevrolet/colorado/i-2004-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-static) or «Cooling System Draining and Filling (Vac N Fill)»(/chevrolet/colorado/i-2004-2012/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-vac) .

1. Disconnect the engine wiring harness electrical connector (1) from the mass air flow (MAF)/intake air temperature (IAT) sensor (2).
2. Remove the MAF/IAT sensor screws (1).
3. Remove the MAF/IAT sensor (2) from the air cleaner assembly.

Note. Handle the MAF sensor carefully. Do not drop the MAF sensor in order to prevent damage to the MAF sensor. Do not damage the screen located on the air inlet end of the MAF. Do not touch the sensing elements. Do not allow solvents and lubricants to come in contact with the sensing elements. Use a small amount of a soap based solution in order to aid in the installation.

1. Insert the MAF/IAT sensor (2) into the air cleaner assembly.
2. Install the MAF/IAT sensor screws (1). Tighten: Tighten the screws to 1.5 N.m (13 lb in).
3. Connect the engine wiring harness electrical connector (1) to the MAF/IAT sensor (2).

1. Disconnect the manifold absolute pressure (MAP) sensor electrical connector (3).
2. Press the retainer locking tabs inward, then pull the retainer (1) up to remove.
3. Remove the MAP sensor (2) from the intake manifold (3).
4. Inspect the MAP sensor seal for damage, and replace as necessary.

1. Lightly lubricate the MAP sensor seal with clean engine oil, to aid in installation.
2. Install the MAP sensor (2) into the intake manifold (3).
3. Install the MAP sensor retainer (1).
4. Connect the MAP sensor electrical connector (3).

J 39194-B Heated Oxygen Sensor Wrench

Note. When replacing the HO2S perform the following: A code clear with a scan tool, regardless of whether or not a DTC is set HO2S heater resistance learn reset with a scan tool, where available Perform the above in order to reset the HO2S resistance learned value and avoid possible HO2S failure.

Note. Refer to Heated Oxygen and Oxygen Sensor Notice .

1. Remove the connector position assurance (CPA) retainer.
2. Disconnect the engine wiring harness electrical connector (1) from the heated oxygen sensor (HO2S) electrical connector.
3. Using the J 39194-B remove the HO2S (2) from the exhaust manifold.

1. Coat the threads of the HO2S with the anti-seize compound P/N 5613695, or equivalent if necessary.
2. Using the J 39194-B , install the HO2S (2) into the exhaust manifold. Tighten: Tighten the HO2S to 42 N.m (31 lb ft).
3. Connect the engine wiring harness electrical connector (1) to the HO2S electrical connector.
4. Install the CPA retainer.

Special Tools

J 39194-B Heated Oxygen Sensor Wrench

Note. When replacing the HO2S perform the following: A code clear with a scan tool, regardless of whether or not a DTC is set HO2S heater resistance learn reset with a scan tool, where available Perform the above in order to reset the HO2S resistance learned value and avoid possible HO2S failure.

Note. Refer to Heated Oxygen and Oxygen Sensor Notice .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. Disconnect the heated oxygen sensor (HO2S) electrical connector (3) from the engine wiring harness connector (1).
3. Using the J 39194-B , remove the HO2S (1) from the catalytic converter.

1. Coat the threads of the HO2S with the anti-seize compound P/N 5613695, or equivalent if necessary.
2. Using the J 39194-B , install the HO2S (1) into the catalytic converter. Tighten: Tighten the HO2S to 42 N.m (31 lb ft).
3. Connect the HO2S electrical connector (3) to the engine wiring harness connector (1).
4. Lower the vehicle.

1. Disconnect the accelerator pedal position (APP) sensor electrical connector.
2. Remove the APP sensor nuts.
3. Remove the APP sensor from the vehicle.

1. Position the APP sensor over the studs.
2. Install the APP sensor nuts. Tighten: Tighten the APP sensor mounting nuts to 9 N.m (80 lb in).
3. Connect the APP sensor electrical connector.
4. Inspect below the pedal for binding, to ensure full range of motion.

1. Remove the air cleaner resonator and outlet duct. Refer to «Air Cleaner Resonator and Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the evaporative emission (EVAP) canister purge pipe (1) from the throttle control module (2). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Disconnect the engine wiring harness electrical connector (1) from the throttle body control module.
4. Remove the throttle control module bolts.
5. Remove the throttle control module and the seal from the intake manifold.
6. Clean the gasket surface.

1. Insert a NEW seal into the intake manifold groove.
2. Position the throttle body control module to the intake manifold.
3. Install the throttle body control module bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
4. Connect the engine wiring harness electrical connector (1) to the throttle body control module.
5. Connect the EVAP canister purge pipe (1) to the throttle control module. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
6. Install the air cleaner resonator and outlet duct. Refer to «Air Cleaner Resonator and Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

Fuel Pressure Relief (With CH 48027)

Tools Required

1. CH-48027 Digital Pressure Gage
2. J 42242 Fuel Pressure Gage Adapter

Relief

1. Remove the engine cover, if required.
2. Loosen the fuel fill cap in order to relieve the fuel tank vapor pressure.
3. Remove the fuel rail service port cap.
4. Wrap a shop towel around the fuel rail service port.
5. Connect the J 42242 to the fuel rail service port.
6. Connect the CH-48027-3 (4) to the J 42242 .
7. Connect the CH-48027-2 (2) to the CH-48027-3 (4).
8. Place the hose on the CH-48027-2 (2) into an approved gasoline container.
9. Open the valve on the CH-48027-2 (2) in order to bleed any fuel from the fuel rail.
10. Close the valve on the CH-48027-2 (2).
11. Remove the hose on the CH-48027-2 (2) from the approved gasoline container.
12. Disconnect the CH-48027-2 (2) from the CH-48027-3 (4).
13. Disconnect the CH-48027-3 (4) from the J 42242 .
14. Disconnect the J 42242 from the fuel rail service port.
15. Remove the shop towel from around the fuel rail service port, and place in an approved gasoline container.
16. Install the fuel rail service port cap.
17. Install the engine cover, if required.
18. Tighten the fuel fill cap.

Fuel Pressure Relief (Without CH 48027)

1. If the fuel system requires repair, prevent fuel spillage by removing the fuel pump fuse. Refer to «Electrical Center Identification Views»(/chevrolet/colorado/i-2004-2012/remont/electrical-component-locations/#wiring-systems-and-power-management-component-connector-end-views) .
2. Loosen the fuel fill cap in order to relieve the fuel tank vapor pressure.
3. Remove the engine cover, if required.
4. Remove the fuel rail service port cap.
5. Wrap a shop towel around the fuel rail service port and using a small flat-bladed tool, depress (open) the fuel rail test port valve.
6. Remove the shop towel from around the fuel rail service port, and place in an approved gasoline container.
7. Install the fuel rail service port cap.
8. Install the engine cover, if required.
9. Tighten the fuel fill cap.

1. CH-48027 Digital Pressure Gage
2. J 42242 Fuel Pressure Gage Adapter

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Connect the CH-48027-1 (1) to the CH-48027-2 (2).
3. Remove the shop towel from around the fuel rail service port, and place in an approved gasoline container.
4. Perform any tests and/or diagnostics as needed. For the proper usage of the CH-48027 , refer to the manufacture's directions.

1. Relieve the fuel system pressure, if required. Perform the following steps: CAUTION: Wrap a shop towel around the fuel pressure connection in order to reduce the risk of fire and personal injury. The towel will absorb any fuel leakage that occurs during the connection of the fuel pressure gage. Place the towel in an approved container when the connection of the fuel pressure gage is complete. Wrap a shop towel around the fuel rail service port. Place the hose on the CH-48027-2 (2) into an approved gasoline container. Open the valve on the CH-48027-2 (2) in order to bleed any fuel from the fuel rail. Close the valve on the CH-48027-2 (2). Remove the hose on the CH-48027-2 (2) from the approved gasoline container. Remove the shop towel from around the fuel rail service port, and place in an approved gasoline container.
2. Disconnect the CH-48027-1 (1) from the CH-48027-2 (2).
3. Disconnect the CH-48027-2 (2) from the CH-48027-3 (4).
4. Disconnect the CH-48027-3 (4) from the J 42242 .
5. Disconnect the J 42242 from the fuel rail service port.
6. Install the fuel rail service port cap.
7. Install the engine cover, if required.
8. Tighten the fuel fill cap.

Tool Required

J 37088-A Fuel Line Disconnect Tool Set

1. Relieve the fuel system pressure before servicing any fuel system connection. Refer to the «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Remove the retainer from the quick-connect fitting.
3. Blow dirt out of the fitting using compressed air.
4. Choose the correct J 37088-A for the size of the fitting. Insert the J 37088-A into the female connector, then push inward in order to release the locking tabs.
5. Pull the connection apart.
6. Using a clean shop towel, wipe off the male pipe end.
7. Inspect both ends of the fitting for dirt and burrs. Clean or replace the components as required.

1. Apply a few drops of clean engine oil to the male pipe end.
2. Push both sides of the quick-connect fitting together in order to snap the retaining tabs into place.
3. Pull on both sides of the quick-connect fitting to make sure the connection is secure.
4. Install the retainer to the quick-connect fitting.
5. Inspect for leaks using the following procedure: Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF, for 10 seconds. Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF. Inspect for leaks.

1. Relieve the fuel system pressure before servicing any fuel system connection. Refer to the «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Using compressed air, blow any dirt out of the quick-connect fitting.
3. This step applies to Bartholomew style connectors ONLY. Squeeze the plastic quick-connect fitting release tabs.
4. This step applies to Q Release style connectors ONLY. Release the fitting by Pushing the tab toward the other side of the slot in the fitting.
5. This step applies to Squeeze to Release style connectors ONLY. Squeeze where indicated by arrows on both sides of the plastic ring surrounding the quick-connect fitting.
6. This step applies to Sliding Retainer style connectors ONLY. Release the fitting by pressing on one side of the release tab causing it to push in slightly. If the tab doesn't move try pressing the tab in from the opposite side. The tab will only move in one direction.
7. Pull the connection apart.
8. Using a clean shop towel, wipe off the male pipe end.
9. Inspect both ends of the fitting for dirt and burrs. Clean or replace the components as required.

1. Apply a few drops of clean engine oil to the male pipe end.
2. Push both sides of the quick-connect fitting together in order to cause the retaining feature to snap into place.
3. Pull on both sides of the quick-connect fitting to make sure the connection is secure.
4. Inspect for leaks using the following procedure: Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF, for 10 seconds. Turn the ignition ON, with the engine OFF for 2 seconds. Turn the ignition OFF. Inspect for leaks.

1. J 36850 Transjel Lubricant
2. J 42960-2 Fuel Flapper Door Holder
3. J 45004 Fuel Tank Drain Hose

Draining

1. Remove the fuel filler cap.
2. Install the J 42960-2 into the fuel fill pipe in order to hold the door open.
3. Insert the J 45004 into the fuel tank until the hose reaches the bottom of the fuel tank.
4. Use an air operated pump device in order to drain the fuel into an approved gasoline container.
5. Simultaneously twist and pull in order to remove the J 45004 from the fuel tank.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Drain the fuel tank. Refer to «Fuel Tank Draining»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
3. Raise and support the vehicle, high enough to access the top of the fuel tank through the wheelhouse liner. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
4. Remove the left rear pickup box wheelhouse liner. Refer to «Pickup Box Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
5. Loosen the fuel fill hose clamp (2) at the fuel tank.
6. Disconnect the evaporative emission (EVAP) line (1) quick connect fitting from the fill tube vent tube. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
7. Separate the fuel fill hose from the fuel tank.
8. Disconnect the chassis wiring harness electrical connectors from the pressure sensor and the module.
9. Disengage the harness from the retainer on the fuel tank.
10. Raise the vehicle completely.
11. Disconnect and remove the middle EVAP vapor line (1) from the fuel tank (3) and the EVAP canister (5). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
12. Disconnect the fuel feed line quick connect fitting from the fuel tank line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
13. Remove the upper fuel tank strap bolt.
14. Remove the upper fuel tank strap.
15. Support the fuel tank with an adjustable jack.
16. Remove the lower fuel tank strap bolt.
17. Remove the lower fuel tank strap.
18. With the aid of an assistant, carefully lower the fuel tank from the vehicle.
19. Place the fuel tank in a suitable work area.
20. If the fuel tank is not being replaced, proceed to the Installation Procedure.

Disassembly Procedure

1. Disconnect the EVAP line (1) quick connect fittings from the module and the vent valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Remove the EVAP line from the clip on the side of the fuel tank.
3. Disengage the EVAP line from the retaining features molded into the fuel tank and remove the EVAP line.
4. Disconnect the fuel feed line (2) quick connect fitting from the module. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
5. Disengage the fuel feed line from the retaining feature molded into the fuel tank and remove the fuel line.
6. Remove the fuel tank module from the fuel tank. Refer to «Fuel Tank Module Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

Assembly Procedure

1. Install the fuel tank module to the fuel tank. Refer to «Fuel Tank Module Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Connect the fuel feed line (2) quick connect fitting to the module. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Engage the fuel feed line to the retaining feature molded into the fuel tank.
4. Connect the EVAP line (1) quick connect fittings to the module and the vent valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
5. Engage the EVAP line to the retaining features molded into the fuel tank.
6. Install the EVAP line to the clip on the side of the fuel tank.

1. With the aid of an assistant, carefully position and support the fuel tank to the vehicle.
2. Install the lower fuel tank strap.
3. Install the lower fuel tank strap bolt. Do not tighten at this time.
4. Install the upper fuel tank strap.
5. Install the upper fuel tank strap bolt. Tighten: Tighten the bolts to 32 N.m (24 lb ft).
6. Connect the fuel feed line quick connect fitting to the fuel tank line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
7. Install and connect the middle EVAP vapor line (1) to the fuel tank (3) and the EVAP canister (5). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
8. Lower the vehicle only enough to gain access to the fuel tank through the wheelhouse.
9. Connect the chassis wiring harness electrical connectors to the pressure sensor and the module.
10. Secure the harness to the retainer on the fuel tank.
11. Install the fuel fill hose to the fuel tank.
12. Connect the fuel tank EVAP line (1) quick connect fitting to the fill tube vent tube. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
13. Tighten the fuel fill hose (2) at the fuel tank. Tighten: Tighten clamp to 2.5 N.m (22 lb in).
14. Install the left rear pickup box wheelhouse liner. Refer to «Pickup Box Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
15. Lower the vehicle.
16. Refill the fuel tank.
17. Install the fuel fill cap.
18. Inspect for leaks. Turn ON the ignition, with the engine OFF for 10 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.

1. Raise and support the vehicle, high enough to access the top of the fuel tank through the wheelhouse liner. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. If the vehicle is crew cab, lower the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Remove the left rear pickup box wheelhouse liner. Refer to «Pickup Box Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
4. Disconnect the chassis wiring harness electrical connector from the fuel tank pressure sensor (1).
5. Pull upward in order to remove the sensor from the fuel tank module.

1. Lightly lubricate the sensor seal with clean engine oil.
2. Press the sensor fully into the fuel tank module.
3. Connect the chassis wiring harness electrical connector to the pressure sensor (1).
4. Install the left rear pickup box wheelhouse liner. Refer to «Pickup Box Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
5. If the vehicle is a crew cab, install the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
6. Lower the vehicle.

1. Remove the fuel tank module. Refer to «Fuel Tank Module Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the fuel level sensor electrical connector from the module cover.
3. Disengage the locking tab (1) on the module bucket.
4. Slide the fuel level sensor downward off from the module bucket.

1. Align the edges of the fuel level sensor with the slots in the module bucket.
2. Slide the fuel level sensor into position, ensure the locking tab (1) is fully engaged.
3. Connect the fuel level sensor electrical connector to the module cover.
4. Install the fuel tank module. Refer to «Fuel Tank Module Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

J 45722 Fuel Sender Lock Ring Tool

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the evaporative emission (EVAP) line (1) quick connect fittings from the module and the vent valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Remove the EVAP line from the clip on the side of the fuel tank.
4. Disengage the EVAP line from the retaining features molded into the fuel tank and remove the EVAP line.
5. Disconnect the fuel feed line (2) quick connect fitting from the module. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
6. Disengage the fuel feed line from the retaining feature molded into the fuel tank and remove the fuel line.
7. Install the J 45722 to the fuel pump module lock ring.
8. Using the J 45722 and a long breaker-bar, rotate the lock ring in a counterclockwise direction in order to unlock the lock ring.
9. Remove the J 45722 from the fuel pump module lock ring.
10. Raise the fuel pump module up from the fuel tank. Tilt the module in order to allow the fuel level sensor arm and float to clear the module opening.
11. Remove the fuel pump module.
12. Remove and discard the fuel pump module seal. CAUTION: Drain the fuel from the fuel sender assembly into an approved container in order to reduce the risk of fire and personal injury. Never store the fuel in an open container.
13. Clean the fuel pump module sealing surface.
14. Place the lock ring on a flat surface. Measure the clearance between the lock ring and the flat surface using a feeler gage at 7 points.
15. If warpage is less than 0.41 mm (0.016 in), the lock ring does not require replacement.
16. If warpage is greater than 0.14 mm (0.016 in), the lock ring must be replaced.

1. Clean any contamination from the male pipe ends of the fuel pump module.
2. Place a NEW fuel tank module seal onto the fuel tank.
3. Insert the fuel pump module into the fuel tank allowing the sensor arm and float to clear module opening.
4. Lower the module down into the fuel tank.
5. Press the fuel tank module downward, aligning the tang with the notch in the fuel tank.
6. Install the fuel pump module lock ring onto the fuel tank.
7. Install the J 45722 to the fuel pump module lock ring.
8. Using the J 45722 and a long breaker-bar, rotate the lock ring in a clockwise direction on order to lock the lock ring.
9. Remove the J 45722 from the fuel pump module lock ring
10. Connect the fuel feed line (2) quick connect fitting to the module. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
11. Engage the fuel feed line to the retaining feature molded into the fuel tank.
12. Connect the EVAP line (1) quick connect fittings to the module and the vent valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2)
13. Engage the EVAP line to the retaining feature molded into the fuel tank.
14. Install the EVAP line to the clip on the side of the fuel tank.
15. Install the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Disconnect the fuel feed line quick connect fitting (1) from the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Disconnect the evaporative emission (EVAP) line quick connect fitting (2) from the EVAP canister purge solenoid valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. If equipped with an automatic transmission perform the following steps, disengage the EVAP/fuel pipe clips (1) from the oil level indicator tube bracket and the engine wiring harness bracket.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
6. Disengage the EVAP/fuel pipe clip (2) from the fuel pipe bracket.
7. Disengage the EVAP/fuel pipe clip (3) from the transmission range selector lever bracket.
8. If equipped with a manual transmission perform the following steps, disengage the EVAP/fuel pipe clips (1) from the oil level indicator tube bracket and the engine wiring harness bracket.
9. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
10. Disengage the EVAP/fuel pipe clips (1 and 2) from the fuel pipe brackets.
11. Disconnect the chassis fuel feed (2) and EVAP (1) line quick connect fittings from the engine lines. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
12. Remove the EVAP/fuel engine line assembly from the vehicle.
13. Open the fuel feed and EVAP line clips (1).
14. Remove the fuel feed line (2) from the clips.

1. Install the fuel feed line (2) to the clips.
2. Close the fuel feed and EVAP line clips (1).
3. Position the EVAP/fuel line assembly up into the engine compartment along the engine and transmission.
4. Connect the chassis fuel feed (2) and EVAP (1) line quick connect fittings to the engine lines. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
5. If equipped with a manual transmission perform the following steps, engage the EVAP/fuel pipe clips (1 and 2) to the fuel pipe brackets.
6. Lower the vehicle.
7. Engage the EVAP/fuel pipe clips (1) to the oil level indicator tube bracket and the engine wiring harness bracket.
8. If equipped with an automatic transmission perform the following steps, engage the EVAP/fuel pipe clip (3) to the transmission range selector lever bracket.
9. Engage the EVAP/fuel pipe clip (2) to the fuel pipe bracket.
10. Lower the vehicle.
11. Engage the EVAP/fuel pipe clips (1) to the oil level indicator tube bracket and the engine wiring harness bracket.
12. Connect the EVAP line quick connect fitting (2) to the EVAP canister purge solenoid valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
13. Connect the fuel feed line quick connect fitting (1) to the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
14. Inspect for leaks. Turn ON the ignition, with the engine OFF for 10 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
3. Disconnect the chassis fuel feed line quick connect fitting (2) from the engine line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Disconnect the chassis fuel feed line quick connect fitting from the fuel tank line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
5. Disengage the fuel feed line from the clips (1).
6. Remove the chassis fuel feed line (2) from the vehicle.

1. Position the chassis fuel feed line (2) to the vehicle.
2. Engage the fuel feed line to the clips (1).
3. Connect the chassis fuel feed line quick connect fitting to the fuel tank line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Connect the chassis fuel feed line quick connect fitting (2) to the engine line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
5. Lower the vehicle.
6. Inspect for leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition, for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.

1. Partially drain the fuel tank below the level of the fuel fill tube. Refer to «Fuel Tank Draining»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
2. Raise and support the vehicle, high enough to access the fuel fill hose through the wheelhouse liner. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
3. Remove the left rear pickup box wheelhouse liner. Refer to «Pickup Box Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
4. Remove the fuel fill hose ground strap bolt.
5. Remove the ground strap from the frame.
6. Loosen the fuel fill hose clamp (2) at the fuel tank.
7. Disconnect the evaporative emission (EVAP) line (1) quick connect fitting from the fill tube vent line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
8. Separate the fuel fill hose from the fuel tank.
9. Remove the fuel fill hose screws.
10. Remove the fuel fill hose from the vehicle.
11. Cap the open end of the fuel tank in order to prevent system contamination.

1. Uncap the fuel tank.
2. Position the fuel fill hose to the fender.
3. Install the fuel fill hose screws. Tighten: Tighten the screws to 2 N.m (18 lb in).
4. Install the fuel fill hose to the fuel tank.
5. Connect the fuel tank EVAP line (1) quick connect fitting to the fill tube vent line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
6. Tighten the fuel fill hose clamp (2) at the fuel tank. Tighten: Tighten the clamp to 2.5 N.m (22 lb in).
7. Install the ground strap to the frame. Ensure that the anti rotation tab is inserted into the hole in the frame.
8. Install the fuel fill hose ground strap bolt. Tighten: Tighten the bolt to 9 N.m (80 lb in).
9. Install the left rear pickup box wheelhouse liner. Refer to «Pickup Box Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
10. Lower the vehicle.
11. Refill the fuel tank.
12. Install the fuel fill cap.

The following procedure covers the disassembly and the inspection of the complete fuel supply system. If the fuel system is contaminated, the fuel system can be cleaned. You can usually determine the extent of the fuel system contamination during the disassembly.

1. Remove the fuel pump module. Refer to «Fuel Tank Module Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Locate the tank in a suitable work area away from any heat, any flame, or any other source of ignition.
3. Inspect the fuel sender strainer. Replace the fuel tank module if the strainer is contaminated.
4. Flush the fuel tank with running hot water for at least five minutes. Pour the water out of the fuel sender assembly opening. Rock the tank in order to ensure that the removal of the water from the tank is complete.
5. Disconnect the fuel feed line from the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
6. Remove the fuel rail and injectors. Refer to «Fuel Injection Fuel Rail Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
7. Use compressed air in order to apply air pressure to the fuel lines in the opposite direction from the normal fuel flow.
8. Clean and inspect the fuel rail and injectors.

1. Install the fuel rail and injectors. Refer to «Fuel Injection Fuel Rail Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Install the fuel pump module. Refer to «Fuel Tank Module Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Connect the fuel feed line to the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Disconnect the fuel feed line quick connect fitting (1) from the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Disconnect the evaporative emission (EVAP) purge tube from the throttle body control module (2) and the EVAP canister purge solenoid valve (3). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Remove the intake manifold. Refer to «Intake Manifold Replacement»(/chevrolet/colorado/i-2004-2012/remont/mechanical/#engine-mechanical-37l) .
5. Disconnect the engine wiring harness electrical connector (1) from the fuel injector harness electrical connector.
6. Before removal, clean the fuel rail assembly and the cylinder head with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. Do not soak the fuel rail in liquid cleaning solvent.
7. Remove the fuel rail bolts.
8. Remove the fuel rail from the cylinder head.
9. Remove and discard the fuel injector lower O-ring seals from each fuel injector.
10. If the fuel rail is not being replaced, proceed to the Installation Procedure.

1. Remove the fuel injector harness clips from the fuel rail and remove the harness (1).
2. Remove the fuel injector retainers (2).
3. Remove the fuel injectors (4).
4. Remove the fuel injector upper O-ring seals (3) from the injectors.

1. Lightly lubricate the NEW upper O-ring seals (3) with mineral oil GM P/N 9981704.
2. Install the NEW upper O-ring seals (3) onto the fuel injectors.
3. Install the fuel injectors (4).
4. Install the fuel injector retainers (2).
5. Position the harness (1) and install the fuel injector harness clips to the fuel rail.

1. Lightly lubricate the NEW lower O-ring seals with mineral oil GM P/N 9981704.
2. Install the NEW O-ring seals onto the tip of each injector.
3. Position the fuel rail to the cylinder head, insert the spray tip ends of the fuel injectors into the cylinder head.
4. Install the fuel rail bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
5. Connect the engine wiring harness electrical connector (1) to the fuel injector harness electrical connector.
6. Install the intake manifold. Refer to «Intake Manifold Replacement»(/chevrolet/colorado/i-2004-2012/remont/mechanical/#engine-mechanical-37l) .
7. Connect the EVAP purge tube to the throttle body control module (2) and the EVAP canister purge solenoid valve (3). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
8. Connect the fuel feed line quick connect fitting (1) to the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
9. Inspect for leaks. Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.

Fuel Injector Replacement

Note. Use care in removing the fuel injectors in order to prevent damage to the fuel injector electrical connector pins or the fuel injector nozzles. Do not immerse the fuel injector in any type of cleaner. The fuel injector is an electrical component and may be damaged by this cleaning method.

1. Remove the fuel rail assembly. Refer to «Fuel Injection Fuel Rail Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the fuel injector harness connector from the fuel injector.
3. Remove and discard the fuel injector retainer clip (1).
4. Remove the fuel injector from the fuel rail.
5. Remove and discard the fuel injector O-ring seals (2 and 3) from the injector.

Scheme 14

The fuel injector (1) is stamped with a part number identification (2). A 4 digit build date code (3) indicates the month (4), day (5), year (6), and the shift (7) that built the injector.

1. Lightly lubricate the NEW fuel injector O-ring seals (2 and 3) with GM P/N 9981704.
2. Install the NEW fuel injector O-ring seals onto the fuel injector.
3. Install a NEW retainer clip (1) to the fuel injector.
4. Push the fuel injector into the rail socket with the electrical connector end facing outward. The retainer clip locks onto the flange of the fuel rail injector socket.
5. Connect the fuel injector harness connector to the fuel injector.
6. Install the fuel rail assembly. Refer to «Fuel Injection Fuel Rail Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

1. Raise and support the vehicle only high enough to access the evaporative emission (EVAP) canister purge solenoid valve through the wheelhouse. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. Remove the left wheelhouse liner. Refer to «Front Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
3. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to disconnect the following from the EVAP canister purge solenoid valve (3): The EVAP purge hose/pipe The EVAP purge hose (1)
4. Disconnect the electrical connector from the EVAP canister purge solenoid valve.
5. Remove the bolt securing EVAP canister purge solenoid valve to the engine.
6. Remove the EVAP canister purge solenoid valve from the engine.

1. Position the EVAP canister purge solenoid valve to the engine.
2. Install the bolt securing EVAP canister purge solenoid valve to the engine. Tighten: Tighten the EVAP canister purge solenoid valve bolt to 10 N.m (89 lb in).
3. Connect the electrical connector to the EVAP canister purge solenoid valve.
4. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to connect the following to the EVAP canister purge solenoid valve (3): The EVAP purge hose/pipe The EVAP purge hose (1)
5. Install the left wheelhouse liner. Refer to «Front Wheelhouse Liner Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
6. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. Disconnect the electrical connector from the evaporative emission (EVAP) canister vent solenoid valve (4).
3. Disconnect the EVAP canister vent solenoid valve (4) from the EVAP canister (5). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Disengage the bracket retaining tab and remove the EVAP canister vent solenoid valve (4).

1. Slide the EVAP canister vent solenoid valve (4) over the bracket. Ensure the valve (4) is properly retained to the bracket.
2. Connect the EVAP canister vent solenoid valve (4) to the EVAP canister (5). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Connect the electrical connector to the EVAP canister vent solenoid valve (4).
4. Lower the vehicle.

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

1. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to disconnect the evaporative emission (EVAP) hose (1) from the following: The throttle body assembly (2) The EVAP canister purge solenoid valve (3)
2. Remove the EVAP hose (1) from the engine.

1. Position the EVAP hose (1) to the engine.
2. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to connect the EVAP hose to the following: The throttle body assembly (2) The EVAP canister purge solenoid valve (3)

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the evaporative emission (EVAP) line (1) quick connect fittings from the module and the vent valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Remove the EVAP line from the clip on the side of the fuel tank.
4. Disengage the EVAP line from the retaining features molded into the fuel tank and remove the EVAP line.

1. Connect the EVAP line (1) quick connect fittings to the module and the vent valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Engage the EVAP line to the retaining features molded into the fuel tank.
3. Install the EVAP line to the clip on the side of the fuel tank.
4. Install the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to disconnect the evaporative emission (EVAP) hoses (1, 3) from the following: The EVAP canister (5) The vent valve
3. Disengage the EVAP hose (3) from the retaining clip on the fuel tank.

1. Secure the EVAP hose (3) to the retaining clip on the fuel tank.
2. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to connect the EVAP hoses (1, 3) to the following: The EVAP canister (5) The vent valve
3. Lower the vehicle.

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

Note. Do not attempt to straighten kinked nylon pipes. Replace any kinked nylon pipes in order to prevent damage to the vehicle. Do not attempt to repair sections of nylon pipes. Replace damaged nylon pipes. Replace the vapor hoses/pipes with original equipment or parts that meet GM specifications.

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the evaporative emission (EVAP) line quick connect fitting (1) from the engine EVAP line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Disconnect the chassis EVAP line (2) quick connect fitting from the EVAP canister (5). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Disengage the EVAP pipe from the retaining clips.
5. Remove the EVAP pipe from the vehicle.

1. Position the chassis EVAP line (1) to the vehicle along the frame.
2. Secure the chassis EVAP line to the frame clips.
3. Connect the chassis EVAP line (2) quick connect fitting to the EVAP canister (5). Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Connect the chassis EVAP line quick connect fitting (1) to the engine EVAP line. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
5. Install the fuel tank. Refer to «Fuel Tank Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-with-ch-48027) or «Fuel Pressure Relief (Without CH 48027)»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2__fuel-pressure-relief-without-ch-48027) .
2. Disconnect the fuel feed line quick connect fitting (1) from the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Disconnect the evaporative emission (EVAP) line quick connect fitting (2) from the EVAP canister purge solenoid valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. If equipped with an automatic transmission perform the following steps, disengage the EVAP/fuel pipe clips (1) from the oil level indicator tube bracket and the engine wiring harness bracket.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
6. Disengage the EVAP/fuel pipe clip (2) from the fuel pipe bracket.
7. Disengage the EVAP/fuel pipe clip (3) from the transmission range selector lever bracket.
8. If equipped with a manual transmission perform the following steps, disengage the EVAP/fuel pipe clips (1) from the oil level indicator tube bracket and the engine wiring harness bracket.
9. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
10. Disengage the EVAP/fuel pipe clips (1 and 2) from the fuel pipe brackets.
11. Disconnect the chassis fuel feed (2) and EVAP (1) line quick connect fittings from the engine lines. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2)
12. Remove the EVAP/fuel engine line assembly from the vehicle.
13. Open the fuel feed and EVAP line clips (1).
14. Remove the EVAP line (3) from the clips.

1. Install the EVAP line (3) to the clips.
2. Close the fuel feed and EVAP line clips (1).
3. Position the EVAP/fuel line assembly up into the engine compartment along the engine and transmission.
4. Connect the chassis fuel feed (2) and EVAP (1) line quick connect fittings to the engine lines. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2)
5. If equipped with a manual transmission perform the following steps, engage the EVAP/fuel pipe clips (1 and 2) to the fuel pipe brackets.
6. Lower the vehicle.
7. Engage the EVAP/fuel pipe clips (1) to the oil level indicator tube bracket and the engine wiring harness bracket.
8. If equipped with an automatic transmission perform the following steps, engage the EVAP/fuel pipe clip (3) to the transmission range selector lever bracket.
9. Engage the EVAP/fuel pipe clip (2) to the fuel pipe bracket.
10. Lower the vehicle.
11. Engage the EVAP/fuel pipe clips (1) to the oil level indicator tube bracket and the engine wiring harness bracket.
12. Connect the EVAP line quick connect fitting (2) to the EVAP canister purge solenoid valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
13. Connect the fuel feed line quick connect fitting (1) to the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
14. Inspect for leaks using the following procedure: Turn ON the ignition, with the engine OFF for 2 seconds. Turn OFF the ignition, for 10 seconds. Turn ON the ignition, with the engine OFF. Inspect for fuel leaks.

Note. Refer to Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. Disconnect the electrical connector from the evaporative emission (EVAP) canister vent solenoid valve (4).
3. Disengage the bracket retaining tab and remove the EVAP canister vent solenoid valve (4).
4. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to disconnect the following from the EVAP canister (5): The EVAP vent hose (1) The EVAP chassis hose/pipe (2) The EVAP canister vent solenoid valve (4)
5. Remove the bolt (2) securing the EVAP canister (1) to the crossmember.
6. Disengage the EVAP canister (1) from the crossmember bracket tabs (3).
7. Remove the EVAP canister (1) from the vehicle.

1. Position the EVAP canister (1) to the crossmember bracket tabs (3).
2. Install the bolt (2) securing the EVAP canister (1) to the crossmember. Tighten: Tighten the EVAP canister bolt to 25 N.m (18 lb ft).
3. Slide the EVAP canister vent solenoid valve (4) over the bracket. Ensure the valve (4) is properly retained to the bracket.
4. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) in order to connect the following to the EVAP canister (5): The EVAP vent hose (1) The EVAP chassis hose/pipe (2) The EVAP canister vent solenoid valve (4)
5. Connect the electrical connector to the EVAP canister vent solenoid valve (4).
6. Lower the vehicle.

1. Remove the air cleaner resonator and outlet duct. Refer to «Air Cleaner Resonator and Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the engine wiring harness electrical connector (1) from the oil pressure sensor (2).
3. Disconnect the engine wiring harness electrical connectors from the ignition coils.
4. Remove the ignition coil bolts.
5. Remove the ignition coils from the camshaft cover.

1. Install the ignition coils into the camshaft cover.
2. Install the ignition coil bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
3. Connect the engine wiring harness electrical connectors to the ignition coils.
4. Install the air cleaner resonator and outlet duct. Refer to «Air Cleaner Resonator and Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

Spark Plug Usage

1. Ensure that the correct spark plug is installed. An incorrect spark plug causes driveability conditions. Refer to «Ignition System Specifications»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2__ignition-system-specifications) for the correct spark plug.
2. Ensure that the spark plug has the correct heat range. An incorrect heat range causes the following conditions: Spark plug fouling-Colder plug Pre-ignition causing spark plug and/or engine damage-Hotter plug

Spark Plug Inspection

1. Inspect the terminal post (1) for damage. Inspect for a bent or broken terminal post (1). Test for a loose terminal post (1) by twisting and pulling the post. The terminal post (1) should NOT move.
2. Inspect the insulator (2) for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator (2) between the terminal post (1) and ground. Inspect for the following conditions: Inspect the spark plug boot for damage. Inspect the spark plug recess area of the cylinder head for moisture, such as oil, coolant, or water. A spark plug boot that is saturated causes arcing to ground.
3. Inspect the insulator (2) for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes (3, 4).
4. Inspect for evidence of improper arcing. Measure the gap between the center electrode (4) and the side electrode (3) terminals. An excessively wide electrode gap can prevent correct spark plug operation. Inspect for the correct spark plug torque. Refer to «Ignition System Specifications»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2__ignition-system-specifications) . Insufficient torque can prevent correct spark plug operation. An over torqued spark plug, causes the insulator (2) to crack. Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode (4). Inspect for a broken or worn side electrode (3). Inspect for a broken, worn, or loose center electrode (4) by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode (4) reduces the spark intensity. Inspect for bridged electrodes (3, 4). Deposits on the electrodes (3, 4) reduce or eliminates the gap. Inspect for worn or missing platinum pads on the electrodes (3, 4), if equipped. Inspect for excessive fouling.
5. Inspect the spark plug recess area of the cylinder head for debris. Dirty or damaged threads can cause the spark plug not to seat correctly during installation.

Spark Plug Visual Inspection

1. Normal operation-Brown to grayish-tan with small amounts of white powdery deposits are normal combustion by-products from fuels with additives.
2. Carbon fouled-Dry, fluffy black carbon, or soot caused by the following conditions: Rich fuel mixtures Leaking fuel injectors Excessive fuel pressure Restricted air filter element Incorrect combustion Reduced ignition system voltage output Weak coils Worn ignition wires Incorrect spark plug gap Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off.
3. Deposit fouling-Oil, coolant, or additives that include substances such as silicone, very white coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.

1. Remove the ignition coils. Refer to «Ignition Coil Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Clean the spark plug recesses with low pressure air.
3. Remove the spark plugs from the cylinder head.
4. Inspect the spark plugs. Refer to «Spark Plug Inspection»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2__spark-plug-inspection) .

1. Measure the spark plug gap on the spark plugs to be installed. Compare the measurement to the gap specifications. Refer to «Ignition System Specifications»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2__ignition-system-specifications) , correct as necessary.
2. Install the spark plugs to the cylinder head. Tighten: Tighten the spark plugs to 18 N.m (13 lb ft).
3. Install the ignition coils. Refer to «Ignition Coil Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. Disconnect the engine wiring harness electrical connector (3) from the crankshaft position (CKP) sensor (1).
3. Remove the CKP sensor bolt.
4. Remove the CKP sensor from the engine block. Discard the O-ring seals.

1. Install new O-ring seals to the CKP sensor.
2. Lightly lubricate the O-ring seals with clean engine oil.
3. Install the CKP sensor into the engine block.
4. Add sealer GM P/N 12346004 (Canadian P/N 10953480) to the CKP sensor bolt threads.
5. Install the CKP sensor bolt. Tighten: Tighten the CKP sensor bolt to 10 N.m (89 lb in).
6. Connect the engine wiring harness electrical connector (3) to the CKP sensor (1).
7. Lower the vehicle.
8. Perform the CKP System Variation Learn Procedure. Refer to «Crankshaft Position System Variation Learn»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2__crankshaft-position-system-variation-learn) .

1. Disconnect the engine wiring harness electrical connector (4) from the exhaust camshaft position (CMP) sensor (5).
2. Remove the exhaust CMP sensor retaining bolt.
3. Remove the exhaust CMP sensor from the cylinder head.

1. Lightly lubricate the O-ring seal with clean engine oil.
2. Install the exhaust CMP sensor into the cylinder head.
3. Install the exhaust CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
4. Connect the engine wiring harness electrical connector (4) to the exhaust CMP sensor (5).

1. Disconnect the engine wiring harness electrical connector from the intake camshaft position (CMP) sensor.
2. Remove the intake CMP sensor retaining bolt.
3. Remove the intake CMP sensor from the cylinder head.

1. Lightly lubricate the O-ring seal with clean engine oil.
2. Install the intake CMP sensor into the cylinder head.
3. Add sealer GM P/N 12346004 (Canadian P/N 10953480) to the CMP sensor bolt threads.
4. Install the intake CMP sensor bolt. Tighten: Tighten the CMP sensor bolt to 10 N.m (89 lb in).
5. Connect the engine wiring harness electrical connector to the intake CMP sensor.

1. Disconnect the engine wiring harness electrical connector (1) from the camshaft position (CMP) actuator solenoid valve (6).
2. Remove the CMP actuator solenoid valve bolt (3).
3. Remove the CMP actuator solenoid valve (2) from the cylinder head. Discard the O-ring seal.
4. Clean debris from the hole (1).

1. Install a new O-ring seal to the actuator solenoid valve (2).
2. Lightly lubricate the O-ring seal with clean engine oil.
3. Install the CMP actuator solenoid valve (2) into the cylinder head.
4. Install the camshaft position actuator solenoid valve bolt (3). Tighten: Tighten the CMP actuator solenoid valve bolt to 10 N.m (89 lb in).
5. Connect the engine wiring harness electrical connector (1) to the CMP actuator solenoid valve (6).

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
2. Disconnect the engine wiring harness electrical connector from the KS (2).
3. Remove the KS retaining bolt.
4. Remove the KS (2) from the engine block.

1. Install the KS (2) and the retaining bolt to the engine block, positioning the electrical terminals down. Tighten: Tighten the knock sensor (KS) bolt to 25 N.m (18 lb ft).
2. Connect the engine wiring harness electrical connector to the KS (2).
3. Lower the vehicle.

1. Open the hood.
2. From under the hood, disconnect the secondary air injection (AIR) pump inlet hose quick connect fitting (1) from the pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Disconnect the AIR pump outlet hose quick connect fitting (2) from the pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Remove the engine shield. Refer to «Engine Protection Shield Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
5. Disconnect the engine wiring harness electrical connector from the AIR pump wiring harness electrical connector.
6. Squeeze the AIR pump wiring harness electrical connector clip (1) together and push up in order to separate the clip/connector from the bracket.
7. Open the AIR pump wiring harness clip (2) and remove the harness from the clip.
8. Remove the AIR pump nuts (1).
9. Lower the vehicle.
10. Reposition the AIR pump inlet and outlet hoses as necessary in order to remove the pump.
11. Remove the AIR pump.

1. Install the AIR pump.
2. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
3. Install the AIR pump nuts (1). Tighten: Tighten the nuts to 9 N.m (80 lb in).
4. Install the AIR pump wiring harness electrical connector clip (1) to the bracket.
5. Install the AIR pump wiring harness to the clip (2) and close the clip.
6. Connect the engine wiring harness electrical connector to the AIR pump wiring harness electrical connector.
7. Install the engine shield. Refer to «Engine Protection Shield Replacement»(/chevrolet/colorado/i-2004-2012/remont/frames-subframes-crossmembers/#frame-and-underbody) .
8. Position the AIR pump inlet and outlet hoses as necessary.
9. Connect the AIR pump outlet hose quick connect fitting (2) to the pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
10. Connect the AIR pump inlet hose quick connect fitting (1) to the pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
11. Close the hood.

1. Disconnect the secondary air injection (AIR) pump inlet hose (1) quick connect fitting from the air cleaner assembly. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Disconnect the AIR pump inlet hose quick connect fitting (1) from the AIR pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Remove the AIR pump inlet hose from the vehicle.

1. Install the AIR pump inlet hose to the vehicle.
2. Connect the AIR pump inlet hose quick connect fitting (1) to the AIR pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Connect the AIR pump inlet hose (1) quick connect fitting to the air cleaner assembly. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

1. Open the hood.
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
3. Disconnect the secondary air injection (AIR) pump outlet hose quick connect fitting from the AIR check valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Disconnect the AIR pump outlet hose quick connect fitting (2) from the AIR pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
5. Remove the AIR pump outlet hose from the vehicle.

1. Install the AIR pump outlet hose to the vehicle.
2. Connect the AIR pump outlet hose quick connect fitting (2) to the AIR pump. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
3. Connect the AIR pump outlet hose quick connect fitting to the AIR check valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
5. Close the hood.

1. Open the hood.
2. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
3. Disconnect the secondary air injection (AIR) pump outlet hose quick connect fitting from the AIR check valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Disconnect the engine wiring harness electrical connector (1) from the AIR check valve.
5. Remove the AIR check valve studs (3).
6. Remove the AIR check valve (2) and gasket (1). Discard the gasket.

1. Place a NEW AIR check valve gasket (1) between the engine and the valve.
2. Position the AIR check valve (2) to the engine.
3. Install the AIR check valve studs (3). Tighten: Tighten to studs to 25 N.m (18 lb ft).
4. Connect the engine wiring harness electrical connector (1) to the AIR check valve.
5. Connect the AIR pump outlet hose quick connect fitting to the AIR check valve. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
6. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
7. Close the hood.

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
2. Disconnect the engine wiring harness electrical connector (1) from the mass airflow (MAF)/intake air temperature (IAT) sensor (2).
3. Disconnect the secondary air injection (AIR) pump inlet hose (1) quick connect fitting from the air cleaner assembly. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Disengage the 2 air cleaner housing retainers (1).
5. Open the air cleaner housing cover, and remove the air filter element (1).

1. Install the air filter element (1), and close the air cleaner housing cover.
2. Engage the 2 air cleaner housing retainers (1) securing the cover.
3. Connect the AIR pump inlet hose (1) quick connect fitting to the air cleaner assembly. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Connect the engine wiring harness electrical connector (1) to the MAF/IAT sensor (2).
5. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
2. Disconnect the engine wiring harness electrical connector (1) from the mass airflow (MAF)/intake air temperature (IAT) sensor (2).
3. Disconnect the secondary air injection (AIR) pump inlet hose (1) quick connect fitting from the air cleaner assembly. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Remove the air cleaner bolts (2).
5. Remove the air cleaner assembly (1) from the vehicle.

1. Place the air cleaner assembly (1) into the vehicle.
2. Install the air cleaner bolts (2). Tighten: Tighten the bolts to 15 N.m (11 lb ft).
3. Connect the AIR pump inlet hose (1) quick connect fitting to the air cleaner assembly. Refer to «Plastic Collar Quick Connect Fitting Service»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
4. Connect the engine wiring harness electrical connector (1) to the MAF/IAT sensor (2).
5. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .

1. Loosen the air cleaner outlet duct clamp (1) at the air cleaner.
2. Loosen the air cleaner outlet duct clamp (3) at the resonator.
3. Remove the air cleaner outlet duct (2).

1. Install the air cleaner outlet duct (2) to the resonator and the air cleaner.
2. Tighten the air cleaner outlet duct clamp (3) at the resonator.
3. Tighten the air cleaner outlet duct clamp (1) at the air cleaner. Tighten: Tighten the clamps to 6 N.m (53 lb in).

1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Resonator and Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
2. Loosen the air cleaner resonator outlet duct clamp (4).
3. Remove the 2 air cleaner resonator bolts (1).
4. Complete the following in order to remove the air cleaner resonator (2) and outlet duct from the engine: Lift upward on the assembly. Disconnect the following: The crankcase ventilation hose (3) from the camshaft cover The outlet duct (4) from the throttle body Remove the assembly (2) from the engine.

1. Complete the following in order to install the air cleaner resonator (2) and outlet duct to the engine: Position the outlet duct (4) over the throttle body assembly. Install the crankcase ventilation hose (3) to the camshaft cover port. Align the air cleaner outlet resonator bolts (1) with the captured nuts on the camshaft cover.
2. View into the air cleaner resonator to ensure the outlet duct is not rolled under at the throttle body assembly.
3. Properly position the air cleaner resonator outlet duct clamp (4). Tighten: Tighten the clamp (4) to 6 N.m (53 lb in).
4. Install the 2 air cleaner outlet resonator to camshaft cover bolts (1). Tighten: Tighten the bolts to 6 N.m (53 lb in).
5. Install the air cleaner outlet duct. Refer to «Air Cleaner Resonator and Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .

Engine Control Module Description

The engine control module (ECM) interacts with many emission related components and systems, and monitors the emission related components and systems for deterioration. OBD II diagnostics monitor the system performance and a diagnostic trouble code (DTC) sets if the system performance degrades.

The malfunction indicator lamp (MIL) operation and the DTC storage are dictated by the DTC type. A DTC is ranked as a Type A or Type B if the DTC is emissions related. Type C is a non-emissions related DTC.

The ECM is in the engine compartment. The ECM is the control center of the engine controls system. The ECM controls the following components

1. The fuel injection system
2. The ignition system
3. The emission control systems
4. The on-board diagnostics
5. The A/C and fan systems
6. The throttle actuation control (TAC) system

The ECM constantly monitors the information from various sensors and other inputs, and controls the systems that affect the vehicle performance and the emissions. The ECM also performs diagnostic tests on various parts of the system. The ECM can recognize operational problems and alert the driver via the MIL. When the ECM detects a malfunction, the ECM stores a DTC. The condition area is identified by the particular DTC that is set. This aids the technician in making repairs.

ECM Function

The engine control module (ECM) can supply 5 volts or 12 volts to the various sensors or switches. This is done through pull-up resistors to the regulated power supplies within the ECM. In some cases, even an ordinary shop voltmeter will not give an accurate reading because the resistance is too low. Therefore, a DMM with at least 10 megaohms input impedance is required in order to ensure accurate voltage readings.

The ECM controls the output circuits by controlling the ground or the power feed circuit through the transistors or a device called an output driver module.

EEPROM

The electronically erasable programmable read only memory (EEPROM) is a permanent memory that is physically part of the engine control module (ECM). The EEPROM contains program and calibration information that the ECM needs in order to control the powertrain operation.

Special equipment, as well as the correct program and calibration for the vehicle, are required in order to reprogram the ECM.

Data Link Connector (DLC)

The data link connector (DLC) is a 16-pin connector that provides the technician a means of accessing serial data for aid in the diagnosis. This connector allows the technician to use a scan tool in order to monitor the various serial data parameters, and display the DTC information. The DLC is located inside of the drivers compartment, underneath the dash.

Malfunction Indicator Lamp (MIL)

The malfunction indicator lamp (MIL) is inside of the instrument panel cluster (IPC). The MIL is controlled by the engine control module (ECM) and illuminates when the ECM detects a condition that affects the vehicle emissions.

ECM Service Precautions

The engine control module (ECM), by design, can withstand the normal current draws that are associated with the vehicle operations. However, care must be used in order to avoid overloading any of these circuits. When testing for opens or shorts, do not ground or apply voltage to any of the ECM circuits unless the diagnostic procedure instructs you to do so. These circuits should only be tested with a DMM.

Emissions Diagnosis For State I/M Programs

This OBD II equipped vehicle is designed to diagnose any conditions that could lead to excessive levels of the following emissions

1. Hydrocarbons (HC)
2. Carbon monoxide (CO)
3. Oxides of nitrogen (NOx)
4. Evaporative emission (EVAP) system losses

Should this vehicles on-board diagnostic system (ECM) detect a condition that could result in excessive emissions, the ECM turns ON the malfunction indicator lamp (MIL) and stores a DTC that is associated with the condition.

Aftermarket (Add-On) Electrical And Vacuum 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.

Aftermarket, add-on, electrical and vacuum equipment is defined as any equipment installed on a vehicle after leaving the factory that connects to the vehicles electrical or vacuum systems. No allowances have been made in the vehicle design for this type of equipment.

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

Electrostatic Discharge (ESD) Damage

The electronic components that are used in the control systems are often designed to carry very low voltage. The electronic components are susceptible to damage caused by electrostatic discharge. Less than 100 volts of static electricity can cause damage to some electronic components.

There are several ways for a person to become statically charged. The most common methods of charging are by friction and by induction. An example of charging by friction is a person sliding across a car seat.

Charging by induction occurs when a person with well insulated shoes stands near a highly charged object and momentarily touches ground. Charges of the same polarity are drained off leaving the person highly charged with the opposite polarity. Static charges can cause damage, therefore, it is important to use care when handling and testing electronic components.

Emissions Control Information Label

The underhood Vehicle Emissions Control Information Label contains important emission specifications and setting procedures. In the upper right corner is the exhaust emission information. This identifies the year, the manufacturing division of the engine, the displacement of the engine in liters, the class of the vehicle, and type of fuel metering system. There is also an illustrated emission components and vacuum hose schematic.

This label is located in the engine compartment of every General Motors vehicle. If the label has been removed, it can be ordered from GM service parts operations (GMSPO).

Underhood Inspection

Perform a careful underhood inspection when performing any diagnostic procedure or diagnosing the cause of an emission test failure. This can often lead to repairing a condition without further steps. Use the following guidelines when performing an inspection

1. Inspect all of the vacuum hoses for correct routing, pinches, cuts, or disconnects.
2. Inspect any hoses that are difficult to see.
3. Inspect all of the wires in the engine compartment for the following conditions: Burned or chafed spots Pinched wires Contact with sharp edges Contact with hot exhaust manifolds

Scheme 15

The engine control module (ECM) is the control center for the throttle actuator control (TAC) system. The ECM determines the driver's intent based on input form the accelerator pedal position sensors, then calculates the appropriate throttle response based on the throttle position sensors. The ECM achieves throttle positioning by providing a pulse width modulated voltage to the throttle actuator motor. The throttle blade is spring loaded in both directions, and the default position is slightly open.

Normal Mode

During the operation of the TAC system, several modes, or functions, are considered normal. The following modes may be entered during normal operations

1. Minimum pedal value-At key-up, the ECM updates the learned minimum pedal value.
2. Minimum throttle position values-At key-up, the ECM updates the learned minimum throttle position value. In order to learn the minimum throttle position value, the throttle blade is moved to the Closed position.
3. Ice break mode-If the throttle blade is not able to reach a predetermined minimum throttle position, the ice break mode is entered. During the ice break mode, the ECM commands the maximum pulse width several times to the throttle actuator motor in the closing direction.
4. Minimum pedal value-At key-up, the ECM updates the learned minimum pedal value.
5. Battery saver mode-After a predetermined time without engine RPM, the ECM commands the battery saver mode. During the battery saver mode, the TAC module removes the voltage from the motor control circuits, which removes the current draw used to maintain the idle position and allows the throttle to return to the spring loaded default position.

Reduced Engine Power Mode

When the ECM detects a condition with the TAC system, the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions

1. Acceleration limiting-The ECM will continue to use the accelerator pedal for throttle control, however, the vehicle acceleration is limited.
2. Limited throttle mode-The ECM will continue to use the accelerator pedal for throttle control, however, the maximum throttle opening is limited.
3. Throttle default mode-The ECM will turn OFF the throttle actuator motor, and the throttle will return to the spring loaded default position.
4. Forced idle mode-The ECM will perform the following actions: Limit engine speed to idle positioning the throttle position, or by controlling the fuel and spark if the throttle is turned OFF. Ignore the accelerator pedal input.
5. Engine shutdown mode-The ECM will disable fuel and de-energize the throttle actuator.

Scheme 16

Camshaft Position (CMP) Actuator System

The camshaft position (CMP) actuator system is an electro-hydraulic operated device used for a variety of engine performance and operational enhancements. These enhancements include lower emission output through exhaust gas dilution of the intake charge in the combustion chamber, a broader engine torque range, and improved fuel economy. The CMP actuator system accomplishes this by changing the angle or timing of the camshaft relative to the crankshaft position. The CMP actuator simply allows earlier or later intake and exhaust valve opening during the four stroke engine cycle. The CMP actuator cannot vary the duration of valve opening, or the valve lift.

During engine OFF, engine idling conditions, and engine shutdown, the camshaft actuator is held in the Park position. Internal to the CMP actuator assembly is a return spring and a locking pin. During non-phasing modes of the camshaft, the return spring rotates the camshaft back to the Park position, and the locking pin retains the CMP actuator sprocket to the camshaft.

CMP Actuator System Operation

The camshaft position (CMP) actuator system is controlled by the engine control module (ECM). The ECM sends a signal to a CMP actuator solenoid in order to control the amount of engine oil flow to a Cam Actuator passage. The pressurized engine oil is sent to unseat the locking pin, and to the vane and rotor assembly of the CMP actuator. There are 2 different passages for oil to flow through, a passage for cam advance and a passage for cam retard. The Cam Actuator is attached to a camshaft and is hydraulically operated in order to change the angle of the camshaft relative to crankshaft position (CKP). Engine oil pressure (EOP), viscosity, temperature and engine oil level can have an adverse affect on Cam Actuator performance.

Fuel System Overview

The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the fuel tank module, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.

An electric turbine style fuel pump attaches to the fuel tank module inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pressure regulator, a part of the fuel tank module, maintains the correct fuel pressure to the fuel injection system. The fuel tank module contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.

Fuel Tank

The fuel tank stores the fuel supply. The fuel tank is located on the left side of the vehicle. The fuel tank is held in place by 2 metal straps that attach to the frame. The fuel tank is molded from high-density polyethylene.

Scheme 17

The fuel fill pipe has a built-in restrictor in order to prevent refueling with leaded fuel.

Fuel Filler Cap

Note. If a fuel tank filler cap requires replacement, use only a fuel tank filler cap with the same features. Failure to use the correct fuel tank filler cap can result in a serious malfunction of the fuel and EVAP system.

The fuel fill pipe has a tethered fuel filler cap. A torque-limiting device prevents the cap from being over-tightened. To install the cap, turn the cap clockwise until you hear audible clicks. This indicates that the cap is correctly torqued and fully seated. A fuel filler cap that is not fully seated may cause a malfunction in the emission system.

Fuel Tank Module

The fuel tank module consists of the following major components

1. The fuel tank pressure (FTP) sensor
2. The fuel pump
3. The fuel level sensor
4. The fuel filter
5. The fuel pressure regulator
6. The fill limit vent valve

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 position of the float arm. The control module sends the fuel level information via the Class 2 circuit to the instrument panel cluster (IPC). This information is used for the IPC fuel gage and the low fuel warning indicator, if applicable. The control module also monitors the fuel level input for various diagnostics.

Fuel Pump

The fuel pump is mounted in the fuel tank module reservoir. The fuel pump is an electric high-pressure pump. Fuel is pumped to the fuel injection system at a specified flow and pressure. The fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers. The control module controls the electric fuel pump operation through a fuel pump relay. The fuel pump flex pipe acts to dampen the fuel pulses and noise generated by the fuel pump.

Fuel Filter

The fuel filter is contained in the fuel tank module inside the fuel tank. The paper filter element traps particles in the fuel that may damage the fuel injection system. The filter housing is made to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature.

Scheme 18

The fuel pressure regulator (2) is contained in the fuel tank module. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. The fuel pressure regulator is not vacuum biased. Fuel pressure is controlled by a pressure balance across the regulator. The fuel system pressure is constant.

Fuel Feed Pipes

The fuel feed pipe carries fuel from the fuel tank to the fuel injection system. The fuel feed pipe consists of 3 sections

1. The rear fuel pipe is located from the top of the fuel tank to the chassis fuel pipe. The rear fuel pipe is constructed of nylon.
2. The chassis fuel pipe is located under the vehicle and connects the rear fuel pipe to the front fuel pipe. The chassis fuel pipe is constructed of steel.
3. The front fuel pipe connects the chassis fuel pipe to the fuel rail. The front fuel pipe is constructed of steel with a section of flexible hose.

Nylon Fuel Pipes

Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature.

Heat resistant rubber hose or corrugated plastic conduit protect the sections of the pipes that are exposed to chafing, high temperature, or vibration.

Nylon fuel pipes are somewhat flexible and can be formed around gradual turns under the vehicle. However, if nylon fuel pipes are forced into sharp bends, the pipes kink and restrict the fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Take special care when working on a vehicle with nylon fuel pipes.

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.

Scheme 19

The fuel rail assembly attaches to the cylinder head. The fuel rail assembly performs the following functions

1. Positions the fuel injectors in the cylinder head
2. Distributes fuel evenly to the injectors

Scheme 20

The fuel injector assembly is a solenoid device controlled by the control module that meters pressurized fuel to a single engine cylinder. The control module energizes the high-impedance, 12 ohms, injector solenoid (2) to open a normally closed ball valve (3). This allows fuel to flow into the top of the injector, past the ball valve, and through a director plate at the injector outlet. The director plate has four machined holes that control the fuel flow, generating a spray of finely atomized fuel at the injector tip. Fuel from the injector tip is directed at the intake valve, causing the fuel to become further atomized and vaporized before entering the combustion chamber. This fine atomization improves fuel economy and emissions.

Fuel Metering Modes of Operation

The control module monitors voltages from several sensors in order to determine how much fuel to give the engine. The control module controls the amount of fuel delivered to the engine by changing the fuel injector pulse width. The fuel is delivered under one of several modes.

Starting Mode

When the ignition is first turned ON, the control module energizes the fuel pump relay for 2 seconds. This allows the fuel pump to build pressure in the fuel system. The control module calculates the air/fuel ratio based on inputs from the engine coolant temperature (ECT), manifold absolute pressure (MAP), mass air flow (MAF), and throttle position (TP) sensors. The system stays in starting mode until the engine speed reaches a predetermined RPM.

Clear Flood Mode

If the engine floods, clear the engine by pressing the accelerator pedal down to the floor and then crank the engine. When the TP sensor is at wide open throttle (WOT), the control module reduces the fuel injector pulse width in order to increase the air to fuel ratio. The control module holds this injector rate as long as the throttle stays wide open and the engine speed is below a predetermined RPM. If the throttle is not held wide open, the control module returns to the starting mode.

Run Mode

The run mode has 2 conditions called Open Loop and Closed Loop. When the engine is first started and the engine speed is above a predetermined RPM, the system begins Open Loop operation. The control module ignores the signal from the heated oxygen sensor (HO2S). The control module calculates the air/fuel ratio based on inputs from the ECT, MAP, MAF, and TP sensors. The system stays in Open Loop until meeting the following conditions

1. The HO2S has varying voltage output, showing that the HO2S is hot enough to operate properly.
2. The ECT sensor is above a specified temperature.
3. A specific amount of time has elapsed after starting the engine.

Specific values for the above conditions exist for each different engine, and are stored in the electrically erasable programmable read-only memory (EEPROM). The system begins Closed Loop operation after reaching these values. In Closed Loop, the control module calculates the air/fuel ratio, injector ON time, based upon the signal from various sensors, but mainly from the HO2S. This allows the air/fuel ratio to stay very close to 14.7:1.

Acceleration Mode

When the driver pushes on the accelerator pedal, air flow into the cylinders increases rapidly. To prevent possible hesitation, the control module increases the pulse width to the injectors to provide extra fuel during acceleration. This is also known as power enrichment. The control module determines the amount of fuel required based upon the TP, the ECT, the MAP, the MAF, and the engine speed.

Deceleration Mode

When the driver releases the accelerator pedal, air flow into the engine is reduced. The control module monitors the corresponding changes in the TP, the MAF, and the MAP. The control module shuts OFF fuel completely if the deceleration is very rapid, or for long periods, such as long, closed-throttle coast-down. The fuel shuts OFF in order to prevent damage to the catalytic converters.

Battery Voltage Correction Mode

When the battery voltage is low, the control module compensates for the weak spark delivered by the ignition system in the following ways

1. Increasing the amount of fuel delivered
2. Increasing the idle RPM
3. Increasing the ignition dwell time

Fuel Cutoff Mode

The control module cuts OFF fuel from the fuel injectors when the following conditions are met in order to protect the powertrain from damage and improve driveability

1. The ignition is OFF. This prevents engine run-on.
2. The ignition is ON but there is no ignition reference signal. This prevents flooding or backfiring.
3. The engine speed is too high, above red line.
4. The vehicle speed is too high, above rated tire speed.
5. During an extended, high speed, closed throttle coast down-This reduces emissions and increases engine braking.
6. During extended deceleration, in order to prevent damage to the catalytic converters.

Fuel Trim

The control module controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The control module monitors the HO2S signal voltage while in Closed Loop and regulates the fuel delivery by adjusting the pulse width of the injectors based on this signal. The ideal fuel trim values are around 0 percent for both short and long term fuel trim. A positive fuel trim value indicates the control module is adding fuel in order to compensate for a lean condition by increasing the pulse width. A negative fuel trim value indicates that the control module is reducing the amount of fuel in order to compensate for a rich condition by decreasing the pulse width. A change made to the fuel delivery changes the long and short term fuel trim values. The short term fuel trim values change rapidly in response to the HO2S signal voltage. These changes fine tune the engine fueling. The long term fuel trim makes coarse adjustments to fueling in order to re-center and restore control to short term fuel trim. A scan tool can be used to monitor the short and long term fuel trim values. The long term fuel trim diagnostic is based on an average of several of the long term speed load learn cells. The control module selects the cells based on the engine speed and engine load. If the control module detects an excessively lean or rich condition, the control module will set a fuel trim diagnostic trouble code (DTC).

EVAP System Operation

The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valve OFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.

Large Leak Test

This tests for large leaks and restrictions to the purge path in the evaporative emission (EVAP) system. When the enabling criteria has been met, the control module commands the EVAP vent solenoid valve ON and the EVAP purge solenoid valve ON, allowing vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time.

Small Leak Test

The engine off natural vacuum (EONV) diagnostic is the small-leak detection diagnostic for the evaporative emission (EVAP) system. While previous leak detection methods were performed with the engine running, the EONV diagnostic monitors the EVAP system pressure or vacuum with the ignition OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the ignition is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.

The EONV utilizes the temperature changes in the fuel tank immediately following a drive cycle to use the naturally occurring vacuum or pressure in the fuel tank. When the vehicle is driven, the temperature rises in the tank. After the vehicle is parked, the temperature in the tank continues to rise for a period of time, then starts to drop. The EONV diagnostic relies on this temperature change and the corresponding pressure change in a sealed system, to determine if an EVAP system leak is present.

The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in). The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the system is sealed, a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, often little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.

Canister Vent Restriction Test

If the evaporative emission (EVAP) vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge solenoid valve ON, commanding the EVAP vent solenoid valve OFF, and monitoring the fuel tank pressure (FTP) sensor for an increase in vacuum. If the vacuum increases more than a calibrated value, DTC P0446 will set.

Purge Solenoid Valve Leak Test

If the evaporative emission (EVAP) purge solenoid valve does not seal properly fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge solenoid valve OFF and the vent solenoid valve ON, sealing the system, and monitors the fuel tank pressure (FTP) for an increase in vacuum. If the control module detects that the EVAP system vacuum increases above a calibrated value, DTC P0496 will set.

Check Gas Cap Message

The control module sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when a malfunction in the evaporative emission (EVAP) system and a large leak test fails.

EVAP System Components

The evaporative emission (EVAP) system consists of the following components

EVAP Canister

The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.

EVAP Purge Solenoid Valve

The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the control module. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.

EVAP Vent Solenoid Valve

The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module commands the valve ON, closing the valve during some EVAP tests, allowing the system to be tested for leaks.

Fuel Tank Pressure Sensor

The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.

Electronic Ignition (EI) System Operation

The electronic ignition (EI) system produces and controls the high energy secondary spark. This spark ignites the compressed air/fuel mixture at precisely the correct time, providing optimal performance, fuel economy, and control of exhaust emissions. The engine control module (ECM) primarily collects information from the crankshaft position (CKP) and camshaft position (CMP) sensors to control the sequence, dwell, and timing of the spark.

Crankshaft Position (CKP) Sensor

The crankshaft position (CKP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit, and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses CKP sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and to detect cylinder misfire.

Crankshaft Reluctor Wheel

The crankshaft reluctor wheel is part of the crankshaft. The reluctor wheel consists of 58 teeth and a reference gap. Each tooth on the reluctor wheel is spaced 6 degrees apart with a 12-degree space for the reference gap. The pulse from the reference gap is known as the sync pulse. The sync pulse is used to synchronize the coil firing sequence with the crankshaft position, while the other teeth provide cylinder location during a revolution.

Camshaft Position (CMP) Sensor

The camshaft position (CMP) sensor is triggered by a notched reluctor wheel built onto the exhaust camshaft sprocket. The CMP sensor provides four signal pulses every camshaft revolution. Each notch, or feature of the reluctor wheel is of a different size which is used to identify the compression stroke of each cylinder and to enable sequential fuel injection. The CMP sensor is connected to the engine control module (ECM) by the following circuits

1. A 5-volt reference circuit
2. A low reference circuit
3. A signal circuit

Ignition Coil/Module

Each ignition coil/module has the following circuits

1. An ignition voltage circuit
2. A ground
3. An ignition control (IC) circuit
4. A low reference circuit

The engine control module (ECM) controls the individual coils by transmitting timing pulses on the IC circuit of each ignition coil/module to enable a spark event.

The spark plugs are connected to each coil by a short boot. The boot contains a spring that conducts the spark energy from the coil to the spark plug. The spark plug electrode is tipped with platinum for long wear and higher efficiency.

Engine Control Module (ECM)

The engine control module (ECM) controls all ignition system functions, and constantly corrects the spark timing. The ECM monitors information from various sensor inputs that include the following

1. The throttle position (TP) sensor
2. The engine coolant temperature (ECT) sensor
3. The mass air flow (MAF) sensor
4. The intake air temperature (IAT) sensor
5. The vehicle speed sensor (VSS)
6. The engine knock sensor (KS)
7. The manifold absolute pressure (MAP) sensor

Modes of Operation

During normal operation the engine control module (ECM) controls all ignition functions. If either the crankshaft position (CKP) or camshaft position (CMP) sensor signal is lost, the engine will continue to run because the ECM will default to a limp home mode using the remaining sensor input. Each coil is internally protected against damage from excessive voltage. If one or more coils were to fail in this manner, a misfiring condition would result. Diagnostic trouble codes are available to accurately diagnose the ignition system with a scan tool.

Purpose

The knock sensor (KS) system enables the control module to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The control module uses the KS system to test for abnormal engine noise that may indicate detonation, also known as spark knock.

Sensor Description

The knock sensor (KS) system uses a flat response 2-wire sensor. The sensor uses piezo-electric crystal technology that produces an AC voltage signal of varying amplitude and frequency based on the engine vibration, or noise, level. The amplitude and frequency are dependant upon the level of knock that the KS detects. The control module receives the KS signal through two isolated signal circuits.

The control module learns a minimum noise level, or background noise, at idle from the KS and uses calibrated values for the rest of the RPM range. The control module uses the minimum noise level to calculate a noise channel. A normal KS signal will ride within the noise channel. As engine speed and load change, the noise channel upper and lower parameters will change to accommodate the KS signal, keeping the signal within the channel. In order to determine which cylinders are knocking, the control module only uses KS signal information when each cylinder is near top dead center (TDC) of the firing stroke. If knock is present, the signal will range outside of the noise channel.

If the control module has determined that knock is present, it will retard the ignition timing to attempt to eliminate the knock. The control module will always try to work back to a zero compensation level, or no spark retard. An abnormal KS signal will stay outside of the noise channel or will not be present. KS diagnostics are calibrated to detect faults with the KS circuitry inside the control module, the KS wiring, the KS voltage output, or constant noise from an outside influence such as a loose/damaged component or excessive engine mechanical noise.

Secondary Air Injection System Description

The secondary air injection (AIR) system aids in the reduction of hydrocarbon exhaust emissions during a cold start-up. This occurs when the start-up engine coolant temperature (ECT) is between 5-50°C (41-122°F), and the intake air temperature (IAT) is between 5-60°C (41-140°F). The AIR pump operates 5-60 seconds after start-up.

The engine control module (ECM) activates the AIR system by simultaneously supplying grounds to the AIR pump and the AIR valve relays. This action closes the relays' internal contacts. The AIR pump and the AIR control solenoid valve/pressure sensor assembly are in turn energized, the pump runs and the control/shut-off valve opens.

The AIR pump sends pressurized fresh air into the pipes/hoses through the open control/shut-off valve, and into the exhaust manifold. The extra air accelerates the catalyst operation, helping it to reach operating temperature faster. The AIR pump remains ON for a short period of time after the control/shut-off valve is commanded OFF. When the AIR pump is commanded OFF it will not run or be activated until the next vehicle start. When the AIR system is inactive, the closed AIR control/shut-off valve prevents air/exhaust flow in either direction.

The AIR system pressure sensor is used to monitor pressure at the AIR control solenoid valve/pressure sensor assembly inlet during the commanded ON/OFF states.

The AIR system includes the following components

1. The AIR pump-The electric AIR pump supplies pressurized, filtered air to the AIR control/shut-off valve. The AIR pump is a turbine type pump that is permanently lubricated and requires no periodic maintenance.
2. The AIR solenoid-The AIR solenoids opens the AIR control/shut-off valve when the solenoid is energized by the AIR solenoid relay.
3. The AIR control solenoid valve/pressure sensor assembly-The AIR control solenoid valve/pressure sensor assembly has a solenoid mounted valve. When the valve is open by the solenoid, pressurized air from the AIR pump flows through the control solenoid valve/pressure sensor assembly and is directed into the exhaust manifold through an outlet pipe.
4. The AIR pressure sensor-The AIR pressure sensor is a part of the AIR control solenoid valve/pressure sensor assembly. The sensor is a 3-wire sensor that measures the AIR system pressure at the AIR control solenoid valve/pressure sensor assembly inlet.
5. The AIR pump relay-The AIR pump relay supplies high current and battery voltage to the AIR pump. The ECM commands the relay ON by supplying a ground to the relay control circuit.
6. The AIR valve relay-The AIR valve relay supplies high current and battery voltage to the AIR solenoid. the ECM commands the relay ON by supplying a ground to the relay control circuit.
7. The pipes and hoses-The AIR system hose carries filtered air from the engine air cleaner to the AIR pump inlet. The pipe/hoses carry the air from the AIR pump to the AIR control solenoid valve/pressure sensor assembly and on to the exhaust manifold.
8. The inlet filter-The AIR system does not have a separate inlet air filter. Filtered air is drawn from the engine air cleaner assembly.

Results of Incorrect Operation

The ECM monitors the secondary air injection (AIR) system for faults during cold start-up operation. When the system's pressure or relay circuits operations vary too far from the predicted values, a DTC will set. Diagnostics detect the following conditions

1. A partially blocked or leaking AIR system
2. A malfunctioning AIR pump
3. A malfunctioning AIR control solenoid valve/pressure sensor assembly
4. A malfunctioning AIR pressure sensor
5. A restricted exhaust system, forward of the catalytic converter
6. A malfunctioning AIR pump and AIR valve relay

The following DTCs set when an AIR system fault is detected

1. DTC P0411-An AIR system insufficient airflow fault condition has been detected.
2. DTC P0412-An AIR valve relay coil circuit fault condition has been detected.
3. DTC P0418-An AIR pump relay coil circuit fault condition has been detected.
4. DTC P2430-An AIR pressure sensor stuck in range fault condition has been detected.
5. DTC P2431-An AIR pressure sensor range/performance fault condition has been detected.
6. DTC P2432-An AIR pressure sensor signal voltage below the minimum range of the sensor fault condition has been detected.
7. DTC P2433-An AIR pressure sensor signal voltage is above the maximum range of the sensor fault condition has been detected.
8. DTC P2440-An AIR system airflow leak fault condition has been detected.
9. DTC P2444-An AIR pump stuck ON fault condition has been detected.

Air Intake System Description

The primary function of the Air Intake System is to provide filtered air to the engine. The system uses a cleaner element mounted in a housing. The cleaner housing is remotely mounted and uses intake ducts to route the incoming air into the throttle body. The secondary function of the Air Intake System is to muffle air induction noise. This is achieved through the use of resonators attached to the air intake ducts. The resonators are tuned to the specific powertrain. The mass air flow (MAF)/intake air temperature (IAT) sensor is used to measure the temperature and the volume of the air entering the engine.

Special Tools Illustration Tool Number/Description CH-47976 Active Fuel Injector Tester (AFIT) CH-48027 Digital Pressure Gage GE 41415-50 Interrupted Thread Fuel Tank Cap Adapter J 23738-A Mityvac J 26792 HEI Spark Tester J 34730-1A Fuel Pressure Gage J 35616 GM-Approved Terminal Test Kit J 35800-A Fuel Injector Cleaner J 36850 Transjel Lubricant J 37088-A Fuel Line Disconnect Tool J 37287 Fuel Pipe Shut-Off Adapters J 38522 Variable Signal Generator J 39021 Fuel Injector Coil and Balance Tester J 39194-B Heated Oxygen Sensor Wrench J 41413-200 Evaporative Emissions System Tester (EEST) J 41413-SPT High Intensity White Light J 41413-VLV EVAP Service Port Vent Fitting J41415-40 Fuel Tank Cap Adapter J 42242 Fuel Pressure Gage Adapter J 42873-1 3/8 Fuel Line Shut-Off Valve J 42873-2 5/16 Return Pipe Shut-Off Valve J 42960-2 Fuel Flapper Door Holder J 42964-1 3/8 Fuel Pipe Shut-Off Valve J 42964-2 5/16 Fuel Pipe Shut-Off Valve J 43244 Relay Puller Pliers J 44175 Fuel Composition Tester J 45004 Fuel Tank Drain Hose J 45722 Fuel Sender Lock Ring Wrench J 45861 ECT Sensor Socket

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See also:
• DTC P0013
• DTC P0366
• DTC P0856
• DTC P2544
• Control Module References
• Clutch Pedal Position Sensor Learn
• Diagnostic Trouble Code (DTC) List - Vehicle
• Cooling System Draining and Filling (Static Fill)
• Cooling System Draining and Filling (Vac N Fill)
• Component Fastener Tightening Notice
• Fastener Notice
• Heated Oxygen and Oxygen Sensor Notice
• Excessive Force and Oxygen Sensor Notice
• Lifting and Jacking the Vehicle
• Gasoline/Gasoline Vapors Caution
• Electrical Center Identification Views
• Fuel Pressure Relief (With CH 48027)
• Fuel Pressure Relief (Without CH 48027)
• Safety Glasses and Compressed Air Caution
• Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Notice
• Relieving Fuel Pressure Caution
• Fuel Pipe Fitting Caution
• Fuel Tank Draining
• Pickup Box Wheelhouse Liner Replacement
• Fuel and Evaporative Emission Pipe Caution
• Intake Manifold Replacement
• Air Cleaner Resonator and Outlet Duct Replacement
• Ignition System Specifications
• Spark Plug Inspection
• Crankshaft Position System Variation Learn