Engine Controls and Fuel - 3.6l - Introduction Cadillac STS I рестайлинг

Temperature Versus Resistance - Engine Coolant Temperature Sensor

Temperature Versus Resistance - Intake Air Temperature Sensor

Altitude Versus Barometric Pressure

Ignition System 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

Scheme 14

Scheme 15

Scheme 16

Scheme 17

Diagnostic Starting Point - Engine Controls

Begin the system diagnosis with Diagnostic System Check - Vehicle . The Diagnostic System Check - Vehicle will provide the following information

1. The identification of the control modules which command the system
2. The ability of the control modules to communicate through the serial data circuit
3. The identification of any stored DTCs and the codes status

The use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Engine Control Module Replacement

Note. It is necessary to record the remaining engine oil life. If the replacement module is not programed with the remaining engine oil life, the engine oil life will default to 100 percent. If the replacement module is not programmed with the remaining engine oil life, the engine oil will need to be changed at 5000 km (3,000 mi) from the last engine oil change.

Note. It is necessary to record the remaining automatic transmission fluid life. If the replacement module is not programed with the remaining automatic transmission fluid life, the automatic transmission fluid life will default to 100 percent. If the replacement module is not programmed with the remaining automatic transmission fluid life, the automatic transmission fluid will need to be changed at 83000 km (50,000 mi) from the last automatic transmission fluid change.

Removal Procedure

1. Using a scan tool, retrieve the percentage of remaining engine oil and automatic transmission fluid life. Record the remaining engine oil and automatic transmission fluid life.
2. Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection (Side Post)»(/cadillac/sts/i-2007-2011/remont/charging-system/#battery-charging-system-and-starting-system) .
3. Unlock and disconnect the engine wiring harness electrical connectors (1) from the ECM (2).
4. Use the tabs (3) in order to disengage the retainers (2) on the ECM bracket from the ECM (1) and remove the ECM.
5. If replacing the ECM bracket perform the following steps, otherwise proceed to step 4 in the installation procedure.
6. Using a small flat-bladed tool, depress the locking tabs (1) on the ECM bracket.
7. Slide up and remove the ECM bracket (1).

Installation Procedure

1. If replacing the ECM bracket perform the following steps, other wise proceed to step 4.
2. Slide down and install the ECM bracket (1).
3. Ensure that the ECM bracket engages the locking tabs (1).
4. Slide the ECM (1) into the ECM bracket, ensure that the ECM engages the bracket retainers (2).
5. Connect and lock the engine wiring harness electrical connectors (1) to the ECM (2).
6. Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection (Side Post)»(/cadillac/sts/i-2007-2011/remont/charging-system/#battery-charging-system-and-starting-system) .
7. Program the ECM, if required. Refer to «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) .
8. Turn OFF the ignition for a least 5 seconds after the programming event is complete.

Description

The engine control module (ECM) learns the idle position of the throttle body to ensure the correct idle operation. Anytime the ECM or the throttle body is replaced, the ECM must learn the idle position. The engine idle may be unstable or a DTC may set if the idle position is not learned.

Conditions for Running the Idle Learn Procedure

1. DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0638, P2100, P2101, P2105, and P2119 are not set.
2. The engine speed is less than 40 RPM.
3. The vehicle speed is 0 km/h (0 mph).
4. The accelerator pedal position is less than 14.9 percent.
5. The ignition 1 voltage is more than 10 volts.
6. The engine coolant temperature is between 5-85°C (41-185°F).
7. The intake air temperature is between 5-60°C (41-140°F).

Idle Learn Procedure

1. Turn OFF the ignition for 30 seconds.
2. Turn ON the ignition, with the engine OFF for 60 seconds.
3. Turn OFF the ignition.
4. Turn ON the ignition, with the engine OFF.
5. Clear the DTCs with a scan tool.

1. Turn the ignition OFF.
2. Remove the engine oil dipstick indicator.
3. Slide the electrical connector heat protector (1) off the electrical connector.
4. Disconnect the coolant temperature sensor electrical connector.
5. Remove the coolant temperature sensor.

1. Install the coolant temperature sensor and tighten to 22 N.m (16 lb ft).
2. Install the coolant temperature sensor electrical connector.
3. Slide the electrical connector heat protector (1) onto the electrical connector.
4. Inspect and fill the cooling system as necessary. Refer to «Cooling System Draining and Filling (GE 47716)»(/cadillac/sts/i-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system) or «Cooling System Draining and Filling (Static Fill)»(/cadillac/sts/i-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 18

1. Turn the ignition OFF.
2. Remove the fuel injector sight shield, if necessary. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
3. Disconnect the heated oxygen sensor (HO2S) electrical connector.
4. Remove the HO2S electrical connector from the wiring harness bracket.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
6. Remove the HO2S from the catalytic converter.

1. Install the HO2S to the catalytic converterand tighten to 40 N.m (30 lb ft).
2. Lower the vehicle.
3. Install the HO2S electrical connector to the wiring harness bracket.
4. Connect the HO2S electrical connector.
5. Install the fuel injector sight shield, if necessary. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .

1. Turn the ignition OFF.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
3. Disconnect the heated oxygen sensor (HO2S) electrical connector.
4. Remove the HO2S wiring harness from the transmission case.
5. Remove the HO2S.

1. Install the HO2S and tighten to 40 N.m (30 lb ft).
2. Connect the HO2S electrical connector.
3. Install the HO2S wiring harness to the transmission case.
4. Lower the vehicle.

1. Turn the ignition OFF.
2. Remove the fuel injector sight shield, if necessary. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
4. Disconnect the heated oxygen sensor (HO2S) electrical connector.
5. Remove the HO2S electrical connector from the wiring harness bracket.
6. Remove the HO2S.

1. Install the HO2S and tighten to 40 N.m (30 lb ft).
2. Install the HO2S electrical connector to the wiring harness bracket.
3. Connect the HO2S electrical connector.
4. Lower the vehicle.
5. Install the fuel injector sight shield, if necessary. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .

1. Turn the ignition OFF.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
3. Disconnect the heated oxygen sensor (HO2S) electrical connector.
4. Remove the HO2S wiring harness from the transmission case.
5. Remove the HO2S.

1. Install the HO2S and tighten to 40 N.m (30 lb ft).
2. Connect the HO2S electrical connector.
3. Install the HO2S wiring harness to the transmission case.
4. Lower the vehicle.

1. Remove the closeout/insulator panel from under the dashboard on the drivers side. Refer to «Instrument Panel Insulator Panel Replacement - Left Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) or «Instrument Panel Insulator Panel Replacement - Right Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Disconnect the accelerator pedal position (APP) sensor electrical connector from the accelerator pedal module.
3. Remove the nuts from the APP sensor and remove the APP sensor from the front of dash.

1. Install the APP sensor to the front of dash.
2. Install the APP sensor mounting nuts and tighten to 9 N.m (80 lb in).
3. Connect the APP sensor electrical connector.
4. Operate the accelerator pedal and observe the APP angles using a scan tool. The accelerator pedal should operate freely, without binding between closed throttle and wide open throttle.
5. Install the closeout/insulator panel. Refer to «Instrument Panel Insulator Panel Replacement - Left Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) or «Instrument Panel Insulator Panel Replacement - Right Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .

1. Turn the ignition OFF.
2. Remove the air cleaner intake duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Remove the throttle body electrical connector.
4. Unlock and reposition the wiring harness conduit.
5. Remove the throttle body bolts.
6. Remove the throttle body and gasket.

1. Carefully clean the throttle body mounting surfaces of any gasket and/or seal material.
2. Install the throttle body and NEW gasket.
3. Install the throttle body bolts and tighten to 10 N.m (89 lb in).
4. Install the wiring harness conduit.
5. Install the throttle body electrical connector.
6. Install the air cleaner intake duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
7. Perform the throttle learn procedure. Refer to «Throttle Learn»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
8. Use the scan tool to clear all DTCs.

Throttle Body Inspection and Cleaning

1. Remove the air cleaner intake duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Fully open the throttle valve in order to Inspect the throttle body bore and the throttle valve plate for any deposits.
3. Use a clean shop towel and Top Engine Cleaner GM P/N 1052626 or equivalent product in order to clean the throttle body bore and the throttle valve plate. If necessary, use a parts cleaning brush in order to remove heavy deposits.
4. Install the air cleaner duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

Fuel Pressure Relief (With High Pressure Pump - LLT)

1. Install a scan tool to the vehicle and command the fuel pump relay OFF, allowing the low pressure fuel pump to shut off.
2. Start the vehicle and allow the engine to idle until the engine stops. The engine will stop in approximately 20-30 seconds.
3. Turn the ignition OFF.
4. Using the scan tool, verify that there is little to no fuel pressure, if there still is fuel pressure repeat step 2.

Special Tools

CH-48027 Digital Pressure Gage. See Special Tools .

1. If the fuel system requires repair, prevent fuel spillage by removing the fuel pump fuse. Refer to «Electrical Center Identification Views»(/cadillac/sts/i-2007-2011/remont/electrical-component-locations/#wiring-systems-and-power-management-component-views) .
2. Remove the engine cover, if required.
3. Loosen the fuel fill cap in order to relieve the fuel tank vapor pressure.
4. Remove the fuel rail service port cap.
5. Wrap a shop towel around the fuel rail service port.
6. Connect the CH-48027-3 (4) to the fuel rail service port.
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 fuel rail service port.
14. Remove the shop towel from around the fuel rail service port, and place in an approved gasoline container.
15. Install the fuel rail service port cap.
16. Install the engine cover, if required.
17. Tighten the fuel fill cap.

Fuel Pressure Relief (Without CH 48027 - LY7)

1. If the fuel system requires repair, prevent fuel spillage by removing the fuel pump fuse. Refer to «Electrical Center Identification Views»(/cadillac/sts/i-2007-2011/remont/electrical-component-locations/#wiring-systems-and-power-management-component-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.

CH-48027 Digital Pressure Gage. See Special Tools .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
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. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Relieve the fuel system pressure, if required. Perform the following steps: WARNING: 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 fuel rail service port.
5. Install the fuel rail service port cap.
6. Tighten the fuel fill cap.

1. J 37088-A Fuel Line Disconnect Tool Set. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. J 44581 Fuel Line Disconnect Tool. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the retainer from the quick-connect fitting.
3. Blow dirt out of the fitting using compressed air.
4. Depending on the fuel line size and ability to access the fitting, choose the appropriate tool: J 37088-A or J 44581 . See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . Insert the J 37088-A or J 44581 into the female connector, then push inward to release the locking tabs. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
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.
8. 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 to cause the retaining tabs to snap 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.

Disconnect Procedure

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Using compressed air, blow any dirt or debris from around the connection.
3. This step applies to Bartholomew style connector ONLY. Squeeze the plastic quick connect fitting release tabs.
4. This step applies to Release Tab style connector ONLY. Release the fitting by pushing the tab toward the other side of the slot in the fitting.
5. This step applies to the Squeeze to Release style connector ONLY. Squeeze where indicated by the arrows shown above on both sides of the plastic ring surrounding the quick connect fitting.
6. This step applies to the Sliding Retainer style connector ONLY. Release the fitting by pressing on one side of the release tab causing it to push in slightly. If the tab does not move try pressing the tab in from the opposite side. The tab will only move in one direction.
7. This step applies to the Push Down TI style connector ONLY. Release the fitting by pressing on the tab indicated by the arrow.
8. Pull the connection apart.

Connect Procedure

1. Apply a few drops of clean engine oil to the male connection end.
2. Push both sides of the quick-connect fitting together in order to cause the retaining feature to snap into place.
3. Once installed, pull on both sides of the connection in order to make sure the connection is secure.

1. Keep a shop cloth and a container ready to capture any spilled fuel.
2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
4. Remove the rear suspension bracket. Refer to «Rear Suspension Bracket Replacement»(/cadillac/sts/i-2007-2011/remont/suspension-rear/#rear-suspension-system) .
5. Disconnect the quick-connect fitting at the fuel filter inlet. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
6. Using a primary and back-up wrench, remove the threaded fitting at the fuel filter outlet.
7. Slide the fuel filter rearward from the fuel filter bracket.
8. Remove the fuel pipe O-ring seal. Discard the O-ring seal if damaged.
9. Drain any remaining fuel into an approved gasoline container.
10. Discard the fuel filter into an approved container.

1. Lubricate the fuel pipe O-ring seal with clean engine oil.
2. Install the fuel pipe O-ring seal to the fuel pipe.
3. Remove the protective caps from the new fuel filter.
4. Slide the fuel filter forward into the fuel filter bracket.
5. Install the threaded fitting to the fuel filter outlet. Use a back-up wrench in order to prevent the fuel filter from turning and tighten to 30 N.m (22 lb ft).
6. Connect the quick-connect fitting at the fuel filter inlet. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
7. Install the rear suspension bracket. Refer to «Rear Suspension Bracket Replacement»(/cadillac/sts/i-2007-2011/remont/suspension-rear/#rear-suspension-system) .
8. Lower the vehicle.

1. J 36850 Transjel Lubricant
2. J 45004 Fuel Drain Hose. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

Draining Procedure

1. Remove the fuel filler cap.
2. Insert the J 45004 into the fuel tank until the hose reaches the bottom of the fuel tank. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Use an air operated pump device in order to drain the fuel into an approved gasoline container. Up to 26 liters (7 gallons) of residual fuel may remain in the secondary side of the fuel tank.
4. Simultaneously twist and pull in order to remove the J 45004 from the fuel tank. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Drain the fuel tank. Refer to «Fuel Tank Draining»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
3. Remove the exhaust system. Refer to «Exhaust System Replacement»(/cadillac/sts/i-2007-2011/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement) .
4. Remove the rear propeller shaft. Refer to «Rear Propeller Shaft Replacement (AWD)»(/cadillac/sts/i-2007-2011/remont/driveshaft-universal-joints/#propeller-shaft) or «Rear Propeller Shaft Replacement (RWD)»(/cadillac/sts/i-2007-2011/remont/driveshaft-universal-joints/#propeller-shaft) .
5. Remove the rear frame assembly (2). Refer to «Rear Frame Replacement»(/cadillac/sts/i-2007-2011/remont/frames-subframes-crossmembers/#frame-and-underbody) .
6. Disconnect the filler hose (1) from the fuel tank.
7. Disconnect the filler vent tube (2) from the evaporative emission (EVAP) hose. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
8. Disconnect the fuel feed pipe (1) from the chassis bundle. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
9. Disconnect the fuel EVAP hose (2) from the chassis bundle. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
10. Release the electrical connector interlock and disconnect the fuel tank electrical connector.
11. Remove the fuel tank electrical connector retainer from the chassis.
12. Remove the fuel tank electrical harness from the chassis mounted retainer.
13. Disconnect the EVAP hoses from the EVAP canister.
14. Pull outward on the retainer tab in order to disengage the retainer from the chassis.
15. Disconnect the electrical connector from the fuel tank pressure sensor (1).
16. Disconnect the electrical connector from the EVAP canister vent valve.
17. Support the fuel tank with a suitable jack.
18. Remove the fuel tank strap bolts.
19. Remove the fuel tank straps.
20. With the aid of an assistant, carefully lower the fuel tank from the vehicle.
21. Remove the following components if replacing just the fuel tank: The primary fuel tank module-Refer to «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . The secondary fuel tank module-Refer to «Secondary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Install the following components if fuel tank replacement was necessary: The primary fuel tank module-Refer to «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . The secondary fuel tank module-Refer to «Secondary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. With the aid of an assistant, carefully raise the fuel tank to the vehicle.
3. Install the fuel tank straps to the vehicle.
4. Install the fuel tank strap bolts and tighten to 50 N.m (37 lb ft).
5. Connect the filler hose (1) to the fuel tank and tighten to 3.5 N.m (31 lb in).
6. Connect the filler vent tube (2) to the EVAP hose. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
7. Connect the EVAP hoses to the EVAP canister.
8. Connect the EVAP purge valve and fuel tank pressure sensor electrical connectors.
9. Install the fuel tank wire harness and wire harness connector to the retainers on the chassis.
10. Connect the fuel tank electrical connector, and engage the connector interlock.
11. Connect the fuel EVAP hose (2) to the chassis bundle. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
12. Connect the fuel feed pipe (1) to the chassis bundle. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
13. Install the rear frame assembly (2). Refer to «Rear Frame Replacement»(/cadillac/sts/i-2007-2011/remont/frames-subframes-crossmembers/#frame-and-underbody) .
14. Install the propeller shaft. Refer to «Rear Propeller Shaft Replacement (AWD)»(/cadillac/sts/i-2007-2011/remont/driveshaft-universal-joints/#propeller-shaft) or «Rear Propeller Shaft Replacement (RWD)»(/cadillac/sts/i-2007-2011/remont/driveshaft-universal-joints/#propeller-shaft) .
15. Install the exhaust system. Refer to «Exhaust System Replacement»(/cadillac/sts/i-2007-2011/remont/exhaust/#engine-exhaust-system__exhaust-system-replacement) .
16. Refill the fuel tank.
17. Inspect for fuel leaks.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
2. Disconnect the fuel tank pressure sensor electrical connector (1).
3. Remove the fuel tank pressure sensor from the evaporative emission (EVAP) canister.

1. Install the fuel tank pressure sensor to the EVAP canister until fully seated.
2. Connect the fuel tank pressure sensor electrical connector (1).
3. Lower the vehicle.

1. Remove the fuel filler cap.
2. Drain the fuel tank below the level of the fuel filler hose. Refer to «Fuel Tank Draining»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Remove the bolts securing the fuel filler tube to the body.
4. Remove the right rear wheel. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2007-2011/remont/wheel-tire-system/#tires-and-wheels) .
5. Remove the right rear wheelhouse liner. Refer to «Rear Wheelhouse Panel Liner Replacement»(/cadillac/sts/i-2007-2011/remont/frames-subframes-crossmembers/#frame-and-underbody) .
6. Remove the fuel filler tube brace bolt.
7. Disconnect the fuel filler hose (1) from the fuel tank.
8. Disconnect the filler vent tube (2) from the evaporative emission (EVAP) hose. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
9. Remove the fuel filler tube from the vehicle.

1. Position the fuel filler tube to the vehicle.
2. Connect the filler hose (1) to the fuel tank and tighten to 3.5 N.m (31 lb in).
3. Connect the filler vent tube (2) to the EVAP hose. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
4. Install the fuel filler tube brace bolt and tighten to 9 N.m (80 lb in).
5. Install the bolts securing the fuel filler tube to the body and tighten to 3.5 N.m (31 lb in).
6. Install the right rear wheelhouse liner. Refer to «Rear Wheelhouse Panel Liner Replacement»(/cadillac/sts/i-2007-2011/remont/frames-subframes-crossmembers/#frame-and-underbody) .
7. Install the right rear wheel. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2007-2011/remont/wheel-tire-system/#tires-and-wheels) .
8. Add fuel to the fuel tank.
9. Inspect for fuel leaks.
10. Install the fuel filler cap.

J 45722 Fuel Sender Lock Ring Wrench

1. Remove the fuel tank in order to gain access to the primary fuel tank module (1). Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Disconnect the fuel feed hose quick connect fitting (4) from the primary fuel tank module. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Remove the fuel feed hose (2) from the retainer on the fuel tank and position the hose aside.
4. Release the interlock and disconnect the electrical connector (3) from the primary fuel tank module.
5. Remove the wire harness (1) from the retainer on the fuel tank and position the harness aside.
6. Use the J 45722 (2) and a long breaker-bar (1) in order to unlock the fuel tank module lock ring (3), by turning counterclockwise.
7. Remove the cam lock ring.
8. Partially remove the primary fuel tank module (1) in order to gain access to the fuel transfer hose quick connect fitting (3). Use care not to damage the float arm (2).
9. Disconnect the fuel transfer hose quick connect fitting (3).
10. Remove the primary fuel tank module from the fuel tank.
11. Discard the fuel tank module seal (4).
12. 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.
13. If warpage is less than 0.41 mm (0.016 in), the lock ring does not require replacement.
14. If warpage is greater than 0.41 mm (0.016 in), the lock ring must be replaced.

1. Install a NEW fuel tank module seal (4).
2. Grasp the fuel transfer hose from inside the fuel tank.
3. Partially install the primary fuel tank module (1) to the fuel tank.
4. Connect the fuel transfer hose quick connect fitting (3) to the port on the fuel tank module. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
5. Press the primary fuel tank module downward, aligning the module to the encapsulated ring.
6. Position the cam lock ring (3) to the fuel tank.
7. Use the J 45722 (2) and a long breaker-bar (1) to install the fuel tank module lock ring (3), by turning clockwise, until fully seated.
8. Connect the electrical connector (3) to the primary fuel tank module and engage the connector interlock.
9. Install the wire harness (1) to the retainer on the fuel tank.
10. Connect the fuel feed hose quick connect fitting (4) to the primary fuel tank module. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
11. Install the fuel feed hose (2) to the retainer on the fuel tank.
12. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

J 45747 Fuel Sender Unit Wrench. See Special Tools .

1. Remove the fuel tank in order to gain access to the secondary fuel tank module (2). Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Release the interlock and disconnect the electrical connector (1) from the secondary fuel tank module. Position the connector and wire harness aside.
3. Use the J 45747 (1) and a long breaker-bar (2) in order to unlock the fuel tank module lock ring (3), by turning counterclockwise. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
4. Remove the cam lock ring.
5. Partially remove the secondary fuel tank module (2) in order to gain access to the fuel transfer hose quick connect fitting (1). Use care not to damage the float arm (3).
6. Disconnect the fuel transfer hose quick connect fitting (1).
7. Remove the secondary fuel tank module from the fuel tank.
8. Discard the fuel tank module seal (4).
9. 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.
10. If warpage is less than 0.41 mm (0.016 in), the lock ring does not require replacement.
11. If warpage is greater than 0.41 mm (0.016 in), the lock ring must be replaced.

1. Install a NEW fuel tank module seal (4).
2. Grasp the fuel transfer hose from inside the fuel tank.
3. Partially install the secondary fuel tank module (2) to the fuel tank.
4. Connect the fuel transfer hose quick connect fitting (1) to the port on the fuel tank module.
5. Press the secondary fuel tank module downward, aligning the module to the encapsulated ring.
6. Position the cam lock ring (3) to the fuel tank.
7. Use the J 45747 (1) and a long breaker-bar (2) to install the fuel tank module lock ring (3), by turning clockwise, until fully seated. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
8. Connect the electrical connector (1) to the secondary fuel tank module and engage the connector interlock.
9. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Remove the primary fuel tank module. Refer to «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Disconnect the fuel level sensor electrical connector (1) from the module.
3. Complete the following in order to remove the fuel level sensor (1) from the module assembly: Pull the locking tab (2) away from the sensor (1). Slide the sensor (1) away from the module assembly.

1. Complete the following in order to install the fuel level sensor (1) to the module assembly: Align the tabs of the sensor (1) with the slots in the module assembly. Slide the sensor (1) fully into position, ensure the locking tab (2) is engaged.
2. Connect the fuel level sensor electrical connector (1) to the module.
3. Install the primary fuel tank module. Refer to «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Disconnect the fuel lines from the primary fuel tank module. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) and «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Disconnect the hoses from the retaining feature at the fuel tank.

1. Clean any contamination from the male pipe ends of the primary fuel tank module.
2. Connect the hoses to the retaining feature at the fuel tank.
3. Connect the fuel lines from the primary fuel tank module. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) and «Plastic Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
4. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

The fuel system hose/pipes are serviceable individually or as a complete fuel/brake bundle assembly, the following procedure is servicing the fuel hose/pipes individually.

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the fuel pipe retaining clip from the fuel pipe. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Disconnect the fuel pipe (2) from the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
4. Disconnect the evaporative emission (EVAP) purge line (3) from the purge solenoid.
5. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
6. Disconnect the fuel pipes from the fuel filter and the fuel tank bundle.
7. Pull the locking mechanism (1) outward in order to disengage the fuel/brake bundle chassis pipe retainers from the rail.
8. Open the retainers (1) located at the forward portion of the rail in order to remove the chassis hose/pipes.
9. Complete the following in order to remove the chassis hose/pipes from the retainers (2) located at the rearward portion of the rail. Pull the retainers (2) free from the rail. Open the retainers (2) at the top. Remove the chassis hose/pipes from the retainers (2).
10. Pull downward in order to disconnect the fuel/brake bundle chassis pipe retainer from the underbody.
11. Remove the bolt securing the fuel filter bracket to the body.
12. Remove the EVAP hose from the fuel filter bracket.
13. Remove the bolts securing the transmission support to the underbody, from the right side only.
14. Pull the right side transmission support down only enough to allow removal of the chassis fuel hose/pipes.
15. Partially lower the hoist only enough to simultaneously gain access to both the front and rear portions of the chassis fuel hose/pipes.
16. With the aid of an assistant, carefully guide the chassis fuel hose/pipes down through the engine compartment, removing from the bottom.

1. Clean any of the contamination from the male line ends and apply a few drops of clean engine oil.
2. With the aid of an assistant, carefully guide the chassis fuel hose/pipes up through the engine compartment into position.
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
4. Pull the right side transmission support down only enough to allow installation of the chassis fuel hose/pipes.
5. Install the transmission support right side bolts. Refer to «Transmission Support Replacement»(/cadillac/sts/i-2007-2011/remont/frames-subframes-crossmembers/#frame-and-underbody) .
6. Install the EVAP hose to the fuel filter bracket
7. Install the fuel filter bracket bolt and tighten to 9 N.m (80 lb in).
8. Install the fuel/brake bundle to the underbody.
9. Complete the following in order to install the chassis hose/pipes to the retainers (2) located at the rearward portion of the rail: Install the chassis hose/pipes into the retainers (2). Close the retainers (2) at the top. Insert the retainers (2) into the rail.
10. Install the chassis hose/pipes into the retainers (1) located at the forward portion of the rail.
11. Close the retainers.
12. Push the locking mechanism (1) inward in order to engage the fuel/brake bundle chassis pipe retainers to the rail.
13. Connect the fuel feed pipe and the EVAP hose to the fuel bundle.
14. Lower the vehicle.
15. Connect the evaporative emission (EVAP) purge line (3) to the purge solenoid.
16. Connect the fuel feed pipe (1) to the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
17. Install the fuel pipe retaining clip.

1. Remove the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
2. Remove the high pressure pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Relieve the low side fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
4. Remove the radiator surge tank outlet pipe.
5. Disconnect the fuel feed line quick connect fitting from the fuel feed pipe (2). Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
6. Loosen the fuel feed pipe fitting to the high pressure fuel pump.
7. Remove the fuel feed pipe bolts (4) from the cylinder heads.
8. Remove the fuel feed pipe from the engine and high pressure fuel pump.

1. Ensure that the fuel feed pipe and fuel pump fittings are clean and dry prior to assembly.
2. Position the fuel feed pipe (2) to the cylinder head and high pressure fuel pump.
3. Install the fuel feed pipe fitting to the high pressure fuel pump hand tight.
4. Install the fuel feed pipe bolts (4). Tighten: Tighten the bolts to 50 N.m (37 lb ft). Tighten the fitting to 28 N.m (20 lb ft).
5. Connect the fuel feed line quick connect fitting to the fuel feed pipe (2). Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
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.
7. Install the low side fuel pressure service port cap.
8. Install the fuel tank cap.
9. Install the radiator surge tank outlet pipe.
10. Install the high pressure pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
11. Install the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .

Fuel System Cleaning

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. Inspect the fuel system for contamination of the in-line fuel filter. Replace the filter after cleaning the fuel lines if the filter is plugged or contaminated. Refer to «Fuel Filter Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction)
2. Remove the fuel module assemblies. Refer to «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) and «Secondary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Locate the tank in a suitable work area away from any heat, any flame, or any other source of ignition.
4. Perform the following procedures: Inspect the fuel sender strainer. Replace the primary fuel tank module if the strainer is contaminated. Inspect the secondary fuel tank module for debris. Clean the secondary fuel tank module if debris is found. WARNING: Wear safety glasses when using compressed air, as flying dirt particles may cause eye injury. Use compressed air in order to apply air pressure to the transfer tube.
5. 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.
6. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) in order to disconnect the following quick connect fittings from the fuel rail: The feed hose/pipe The return hose/pipe
7. Use compressed air in order to apply air pressure to the fuel lines in the opposite direction from the normal fuel flow.
8. Remove the fuel injectors and fuel rail.
9. Clean and inspect the fuel injectors and fuel rail.

Assemble the fuel system as follows

1. Install the fuel injectors and fuel rail.
2. Install the fuel module assemblies. Refer to «Primary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) and «Secondary Fuel Tank Module Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) in order to connect the following quick connect fittings to the fuel rail: The feed hose/pipe The return hose/pipe

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Remove the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
4. Remove the foam insulator from the fuel rails.
5. Using a 27 mm socket, remove the fuel pressure sensor (1) from the fuel injection fuel rail (2). Discard the fuel pressure sensor.
6. Allow any fuel to drain from the fuel rail and pressure sensor location.
7. Dry the sealing cone in the fuel rail and the area around the sensor joint with a lint free cloth.
8. Inspect the sealing cone in the fuel rail. The surface should be free of fuel, debris, and burrs.

Note. Applying force to the plastic housing of the sensor will destroy the sensor. To tighten or loosen, only apply force to the attached hexagon.

Note. Ensure that the fuel rail threads have been cleaned of any excess fuel, or the NEW fuel injection fuel rail fuel pressure sensor will NOT seal properly.

1. Lubricate the threads and the sealing cone in the fuel rail with silicon free engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent.
2. Lubricate the threads and sealing cone on the NEW fuel injection fuel rail fuel pressure sensor with silicon free engine oil GM P/N 12345610 (Canadian P/N 993193) or equivalent.
3. Install the NEW fuel pressure sensor (1) to the fuel injection fuel rail (2) hand tight.
4. Remove the NEW fuel injection fuel rail fuel pressure sensor, re-lubricate following steps 1 and 2 above.
5. Install the NEW fuel pressure sensor (1) to the fuel injection fuel rail (2). Tighten: Tighten the sensor to 33 N.m (25 lb ft).
6. Install the foam insulator from the fuel rails.
7. Install the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
8. Inspect for fuel 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.
9. Install the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Remove the fuel pipe shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
4. Remove the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
5. Remove the high pressure fuel pipe. Discard the pipe. Refer to «Fuel Feed Intermediate Pipe Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
6. Remove the fuel rail crossover pipe. Refer to «Fuel Injection Fuel Rail Crossover Tube Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . Discard the pipe.
7. Remove the foam insulator from the fuel rails.
8. Disconnect the fuel pressure sensor electrical connector and cut the wire harness tie straps.
9. Remove the fuel rail (2) bolts (1).
10. Remove the fuel pressure sensor. Refer to «Fuel Pressure Sensor Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
11. Remove and discard the direct fuel injector hold down clamps.
12. Once the fuel rail is removed, remove the fuel injectors and rebuild them. Refer to «Fuel Injector Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Install the rebuilt direct fuel injectors (1) to the cylinder heads. Refer to «Fuel Injector Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Install NEW direct injector hold down clamps to the injector.
3. On a new fuel rail, lubricate the fuel injector cups with silicon free engine oil GM P/N 12345610 (Canadian P/N 9931930) or equivalent.
4. Carefully place the fuel rail (2) into position, placing the front into the fuel rail over the front injector and rotating the rear downward.
5. Install the 2 outer fuel rail bolts first, then the 2 inner bolts, and hand tighten.
6. Tighten the fuel rail bolts in the sequence shown: Tighten: Tighten the Bank 1 fuel rail bolts first pass to 12 N.m (106 lb in). Tighten the Bank 1 fuel rail bolts final pass to 23 N.m (17 lb ft).
7. Install a NEW fuel rail crossover pipe. Refer to «Fuel Injection Fuel Rail Crossover Tube Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
8. Install a NEW high pressure fuel pipe. Refer to «Fuel Feed Intermediate Pipe Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
9. Install the high pressure fuel sensor (1). Refer to «Fuel Pressure Sensor Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
10. Connect the fuel injector wiring harness electrical connector (1) to the fuel injectors, fuel rail and fuel pressure sensor.
11. Inspect for fuel 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.
12. Install the foam insulator from the fuel rails.
13. Install the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
14. Install the fuel pipe shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
15. Install the low side fuel pressure service port cap.
16. Install the fuel tank cap.
17. Install the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the fuel pipe shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Remove the high pressure fuel sensor. Refer to «Fuel Pressure Sensor Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
4. Remove the fuel rail crossover pipe. Refer to «Fuel Injection Fuel Rail Crossover Tube Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . Discard this pipe.
5. Remove the fuel rail bolts (1).
6. Carefully remove the Bank 2 fuel rail (2) from the engine. Lift the rear of the rail to ease removal.
7. Remove and discard the direct fuel injector hold down clamps.
8. Once the fuel rail is removed, remove the fuel injectors and rebuild them. Refer to «Fuel Injector Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Install the rebuilt direct fuel injectors (1) to the cylinder heads. Refer to «Fuel Injector Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Install new direct injector hold down clamps to the injectors.
3. On the new fuel rail, lubricate the fuel injector cups with silicon free engine oil GM P/N 12345610 (Canadian P/N 9931930) or equivalent.
4. Carefully place the fuel rail (2) into position, placing the front into the fuel rail over the front injector and rotating the rear downward.
5. Install the 2 outer fuel rail bolts first, then the 2 inner bolts and hand tighten.
6. Tighten the fuel rail bolts in the sequence shown: Tighten: Tighten the Bank 1 fuel rail bolts first pass to 12 N.m (106 lb in). Tighten the Bank 1 fuel rail bolts a final pass to 23 N.m (17 lb ft).
7. Install a NEW fuel rail crossover pipe. Refer to «Fuel Injection Fuel Rail Crossover Tube Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
8. Install the high pressure fuel sensor. Refer to «Fuel Pressure Sensor Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
9. Connect the fuel injector wiring harness electrical connector (1) from the fuel injectors, fuel rail and fuel pressure sensor.
10. Inspect for fuel 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.
11. Install the fuel pipe shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
12. Install the low side fuel pressure service port cap.
13. Install the fuel tank cap.

1. Remove the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
2. Remove the high pressure pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
4. Remove the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
5. Loosen the fuel rail crossover pipe (1) fitting to the right fuel rail (2).
6. Loosen the fuel rail crossover pipe (1) fitting to the right fuel rail (3).
7. Remove the fuel rail crossover pipe (1) from the vehicle. Discard the pipe.

1. Ensure that the fuel rail crossover pipe, right fuel rails fittings and left fuel rail fittings are clean and dry prior to assembly.
2. Position the fuel rail crossover pipe (1) to the right fuel rails fitting (2) and left fuel rail fitting (3).
3. Tighten the fuel rail crossover pipe fittings. Tighten: Tighten the fittings first pass to 16 N.m (12 lb ft). Tighten the fittings final pass to 32 N.m (24 lb ft).
4. 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.
5. Install the low side fuel pressure service port cap.
6. Install the fuel tank cap.
7. Install the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
8. Install the high pressure pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
9. Install the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .

1. Remove the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
2. Remove the high pressure pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Relieve fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
4. Remove the foam insulator from the pipes.
5. Loosen the high pressure pipe fitting to the high pressure fuel pump (1).
6. Loosen the high pressure pipe fitting to the left fuel rail (3).
7. Remove the high pressure fuel pipe (2) from the vehicle. Discard the pipe.

1. Ensure that the high pressure fuel pipe, fuel rail fitting and fuel pump fitting are clean and dry prior to assembly.
2. Position the high pressure fuel pipe (2) to the high pressure fuel pump fitting (1) and left fuel rail (3). hand tighten the fitting.
3. Tighten the high pressure fuel pipe fitting. Tighten: Tighten the fitting a first pass to 16 N.m (12 lb ft). Tighten the fitting a final pass to 32 N.m (24 lb ft).
4. 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.
5. Install the low side fuel pressure service port cap.
6. Install the fuel tank cap.
7. Install the high pressure pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
8. Install the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .

1. Remove the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
2. Remove the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
3. Remove the intake manifold insulator.
4. Remove the wiper transmission. Refer to «Windshield Wiper Transmission Replacement»(/cadillac/sts/i-2007-2011/remont/wiperwasher-systems/#wiper-system-and-washer-system) .
5. Remove the fuel pipe shield to intake manifold bolts (1).
6. Remove the fuel pipe shield to cylinder bolt (1).
7. Carefully remove the fuel pipe shield from the vehicle. Take care not to damage the insulation behind the shield.

1. Position the fuel pipe shield behind the high pressure fuel pump. Take care not to damage the insulation behind the shield.
2. Install the fuel pipe shield to cylinder bolt (1). Hand tighten at this time.
3. Install the fuel pipe shield to intake manifold bolts (1). Tighten: Tighten the fuel pipe shield to manifold bolts to 23 N.m (17 lb ft). Tighten the fuel pipe shield to head bolt to 10 N.m (89 lb in).
4. Install the wiper transmission. Refer to «Windshield Wiper Transmission Replacement»(/cadillac/sts/i-2007-2011/remont/wiperwasher-systems/#wiper-system-and-washer-system) .
5. Install the fuel injection sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
6. Install the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

EN-48896 HP Fuel Pump Installation Alignment Gage. See Special Tools .

1. Relieve the low and high side fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Remove the high pressure fuel pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
4. Remove the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
5. Remove the wiper module. Refer to «Windshield Wiper Motor Replacement»(/cadillac/sts/i-2007-2011/remont/wiperwasher-systems/#wiper-system-and-washer-system) .
6. Disconnect the engine wiring harness electrical connector from the high pressure fuel pump.
7. Remove the radiator surge tank outlet pipe.
8. Remove the low pressure feed pipe. Refer to «Fuel Feed Pipe Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
9. Remove the high pressure pipe. Refer to «Fuel Feed Intermediate Pipe Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . Discard this pipe.
10. Remove and discard the high pressure fuel pump bolts (4).
11. Remove the high pressure fuel pump (3).
12. Remove and discard the high pressure fuel pump gasket (2).
13. Remove and discard the high pressure fuel pump O-ring.
14. Remove the high pressure fuel pump roller lifter.

1. Use the EN-48896 to ensure that the camshaft lobe is in the base circle position. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) . At base circle the tool will be flush with the head.
2. Lubricate the high pressure fuel pump cylinder head bore and roller lifter with camshaft prelube GM P/N 12345501 (Canadian P/N 992704) or equivalent.
3. Install high pressure fuel pump roller lifter.
4. Install a NEW high pressure fuel pump O-ring.
5. Position the NEW high pressure fuel pump gasket (2) and bolts (4) to the fuel pump.
6. Install the high pressure fuel pump (3) to the cylinder head (1). Force will be required while hand tightening the bolts.
7. Tighten the high pressure fuel pump retaining bolts. Tighten: Tighten the fuel pump bolts to 15 N.m (11 lb ft).
8. Ensure the high pressure fuel pump and fuel rail fittings are clean prior to assembly.
9. Install a NEW high pressure fuel pipe. Refer to «Fuel Feed Intermediate Pipe Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
10. Install the fuel feed pipe to the high pressure fuel pump. Refer to «Fuel Feed Pipe Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
11. Connect the high pressure fuel pump wiring harness.
12. Install the radiator surge tank outlet pipe.
13. Install the fuel tank cap.
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.
15. Install the pressure relief cap to the fuel feed pipe.
16. Install the wiper module. Refer to «Windshield Wiper Motor Replacement»(/cadillac/sts/i-2007-2011/remont/wiperwasher-systems/#wiper-system-and-washer-system) .
17. Install the intake manifold. Refer to «Intake Manifold Replacement»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
18. Install the high pressure fuel pump shield. Refer to «Fuel Pipe Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
19. Install the cross vehicle brace. Refer to «Cross Vehicle Brace Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

1. Relieve the fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the upper intake manifold with the lower intake manifold.
3. Remove the fuel pipe retaining clip.
4. Disconnect the fuel feed pipe (2) from the fuel injector rail. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
5. Use compressed air in order to remove debris from the area where the fuel injectors enter the intake manifold.
6. Remove the fuel rail bolts.
7. Remove the fuel rail with the fuel injectors.
8. Disengage the fuel injector electrical connector lock.
9. Disconnect the fuel injector electrical connector.
10. Remove the fuel injector retainer clip.
11. Remove the fuel injector.
12. Remove and discard the fuel injector seals.

1. Install NEW fuel injector seals.
2. Install the fuel injector.
3. Install the fuel injector retainer clip.
4. Install the fuel injector electrical connector.
5. Engage the fuel injector electrical connector lock.
6. Install the fuel rail with the fuel injectors.
7. Install the fuel rail bolts. Tighten: Tighten the fuel rail bolts to 10 N.m (89 lb in).
8. Connect the fuel feed pipe (2) to the fuel rail. Refer to «Metal Collar Quick Connect Fitting Service»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
9. Install the fuel pipe retaining clip.
10. Install the upper intake manifold.

1. EN-47909 Injector Bore and Sleeve Cleaning Kit. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. EN-48266 Injector Seal Installer and Sizer. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. J 2619-01 Slide Hammer
4. J-37281-A Injector Remover. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
5. J 39313 Spark Plug Port Adapter

1. Relieve the high side fuel system pressure. Refer to «Fuel Pressure Relief (With High Pressure Pump - LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__fuel-pressure-relief-with-high-pressure) .
2. Remove the fuel injection fuel rail assembly. Refer to «Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) or «Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Remove and discard the three fuel injector retaining rings (1).
4. Remove the direct fuel injectors and harness (1) as an assembly, and disconnect the electrical connector (2). If necessary, use the J 2619-01 with the J-37281-A in order to remove the direct fuel injectors evenly. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
5. Remove and discard the following components from the fuel injectors (4). Upper O-ring Seal (1) Plastic Spacer (2) Retaining Ring (3) Isolator Cup (5) Teflon Seal (6)
6. Inspect the fuel rail injector bores and clean with J 39313 , and EN-47909 , if required. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Install the following NEW components to the fuel injectors. Use steps 2 through 8 to install these components. Upper O-ring Seal (1) Plastic Spacer (2) Retaining Ring (3) Isolator Cup (5) Teflon Seal (6)
2. From the EN-48266 , position the EN 48266-1 to the injector tip. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Install a NEW teflon seal onto the EN 48266-1.
4. Pull the NEW teflon seal by hand over the EN 48266-1 and into the groove in the injector.
5. Remove the EN 48266-1 from the injector tip.
6. From the EN-48266 , install the EN 48266-2 to the injector tip. See «Special Tools»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
7. Using the EN 48266-2, resize the teflon seal. Install the EN 48266-2, until it bottoms out against the injector body, and rotate the EN 48266-2 while applying only moderate force 180 degrees in one direction and then 180 degrees back in the other direction.
8. Remove the EN 48266-2.
9. Install the direct fuel injectors and harness (1) as an assembly and connect the electrical connector (2).
10. Install the fuel injection fuel rail assembly. Refer to «Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) or «Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LLT)»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Turn the ignition OFF.
2. Remove the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
3. Disconnect the purge line (3) from the purge valve solenoid.
4. Disconnect the purge valve solenoid electrical connector.
5. Disconnect the purge line from the manifold side of the purge valve solenoid.
6. Remove the purge valve solenoid from the bracket.

1. Install the purge valve solenoid to the bracket.
2. Disconnect the purge line from the manifold side of the purge valve solenoid.
3. Disconnect the purge valve solenoid electrical connector.
4. Connect the purge line (3) to the purge valve solenoid.
5. Install the fuel injector sight shield. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .

1. Remove the evaporative emission (EVAP) canister. Refer to «Evaporative Emission Canister Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Clean away any debris that may be present around the EVAP canister vent valve.
3. Twist the EVAP canister vent valve counterclockwise.
4. Pull the EVAP canister vent valve from the EVAP canister.

1. Insert the EVAP canister vent valve into the EVAP canister.
2. Twist the EVAP canister vent valve clockwise into the locked position.
3. Install the EVAP canister. Refer to «Evaporative Emission Canister Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Remove the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Remove the chassis to canister evaporative emission (EVAP) hose from the following: The body retainer (1) The 3 retaining features (2) on the fuel tank The retainer clip (3)
3. Remove the EVAP hose from the fuel tank.

1. Position the EVAP hose to the fuel tank.
2. Install the chassis to canister EVAP hose to the following: The body retainer (1) The 3 retaining features (2) on the fuel tank The retainer clip (3)
3. Install the fuel tank. Refer to «Fuel Tank Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Remove the rear frame. Refer to «Rear Frame Replacement»(/cadillac/sts/i-2007-2011/remont/frames-subframes-crossmembers/#frame-and-underbody) .
2. Disconnect the evaporative emission (EVAP) hoses from the EVAP canister.
3. Disconnect the electrical connector from the EVAP canister.
4. Remove the EVAP canister retaining nuts.
5. Complete the following in order to remove the EVAP canister: Lower the rear of the canister enough to clear the 2 weld studs. Slide the canister rearward from the body brace.

1. Complete the following in order to install the EVAP canister: Insert the fresh air tube and tab on the canister forward into the body brace. Rotate the rear of the canister up over the 2 weld studs on the floor pan.
2. Install the EVAP canister retaining nuts and tighten to 6 N.m (53 lb in).
3. Connect the EVAP hoses to the EVAP canister.
4. Connect the electrical connector to the EVAP canister.
5. Install the rear frame. Refer to «Rear Frame Replacement»(/cadillac/sts/i-2007-2011/remont/frames-subframes-crossmembers/#frame-and-underbody) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
2. Using a 90 degree pick, disengage the lower filter cover clips.
3. Insert a flat-bladed tool between the filter cover and canister, and push up to disengage the upper clips.
4. Remove and discard the evaporative emission (EVAP) canister filter cover.
5. Remove and discard the EVAP canister filter.
6. Clean the inside of the EVAP canister filter housing with a clean shop towel.

1. Insert a NEW EVAP canister filter into the EVAP canister.
2. Install a NEW EVAP canister filter cover seal to a EVAP NEW canister cover.
3. Snap the EVAP canister filter cover onto the EVAP canister.
4. Lower the vehicle.

J 41413 EVAP Pressure and Purge Station

Inspection Procedure

1. Turn OFF the ignition.
2. Remove the EVAP canister purge valve. Refer to «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Lightly tap the EVAP canister purge valve on a hard surface.
4. Inspect for carbon particles exiting either of the vacuum ports. If no carbon particles were detected, but a blockage was detected during a diagnostic procedure, install the original EVAP canister purge valve. Continue with the cleaning procedure. If carbon particles are found during the inspection procedure, continue with the cleaning procedure. If a diagnostic procedure directed you to replace the EVAP canister purge valve and no carbon particles were detected, replace the EVAP canister purge valve. Return to the published service procedure.

Cleaning Procedure

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
2. Remove the EVAP canister. Refer to «Evaporative Emission Canister Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Turn OFF the main valve on the J 41413 .
4. Disconnect the hose from the diagnostic station pressure regulator.
5. Using a section of vacuum hose, connect one end onto the EVAP pressure/purge diagnostic station pressure regulator.
6. Connect the other end of the vacuum hose to the canister side of the purge pipe.
7. Turn ON the main nitrogen cylinder valve and continue to discharge nitrogen for 15 seconds.
8. If the nitrogen does not clear the blockage, replace the purge pipe.
9. Return the EVAP pressure/purge diagnostic station to the stations original condition.
10. Install a new EVAP canister. Refer to «Evaporative Emission Canister Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
11. Lower the vehicle.
12. Install a new EVAP canister purge valve. Refer to «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
13. Return to the diagnostic table that sent you here.

Scheme 19

1. Turn the ignition OFF.
2. Remove the engine cover. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
3. If you are replacing the ignition coil for cylinder 1 or 3, remove and reposition the intake manifold. Perform the following steps: Disconnect the air cleaner duct from the throttle body. Disconnect the positive crankcase ventilation (PCV) hose from the right bank camshaft cover. NOTE: Do NOT separate the upper intake manifold from the lower intake manifold. Remove the intake manifold bolts. Remove the intake manifold brace bolts (1 and 2) and the brace. Remove and reposition the upper intake manifold with the lower intake manifold in order to gain sufficient clearance for ignition coil removal.
4. Remove the ignition coil electrical connector(s).
5. Remove the ignition coil bolt(s).
6. Remove the ignition coil(s).

1. Install the ignition coil(s).
2. Install the ignition coil bolt(s) and tighten to 10 N.m (89 lb in).
3. Install the ignition coil electrical connector(s).
4. If necessary, install the intake manifold.
5. Install the engine cover. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .

1. Turn the ignition OFF.
2. Remove the engine cover. Refer to «Fuel Injector Sight Shield Replacement (LLT)»(/cadillac/sts/i-2007-2011/remont/mechanical/#engine-mechanical-36l-2-of-6) .
3. If you are replacing the ignition coil for cylinder 2, remove and reposition the intake manifold. Perform the following steps: Disconnect the air cleaner duct from the throttle body. Disconnect the positive crankcase ventilation (PCV) hose from the right bank camshaft cover. NOTE: Do NOT separate the upper intake manifold from the lower intake manifold. Remove the intake manifold bolts. Remove the intake manifold brace bolts (1 and 2) and the brace. Remove and reposition the upper intake manifold with the lower intake manifold in order to gain sufficient clearance for ignition coil removal.
4. Remove the ignition coil electrical connector(s).
5. Remove the ignition coil bolt(s).
6. Remove the ignition coil(s).

1. Install the ignition coil(s).
2. Install the ignition coil bolt(s) and tighten to 10 N.m (89 lb in).
3. Install the ignition coil electrical connector(s).
4. If necessary, install the upper intake manifold.

Spark Plug Operation

Worn or dirty spark plugs may operate well at idle speeds, but frequently fail at higher load. Bad spark plugs are often responsible for the following conditions

1. Power loss
2. Poor fuel economy
3. Loss of speed
4. Hard starting
5. Poor engine performance

Normal spark plug operation results in brown to grayish tan deposits on the area of the spark plug that enters the cylinder. A small amount of reddish brown, yellow, and white powdery residue may also be present on the insulator tip around the center electrode. These deposits are normal combustion by-products of fuels and lubricating oils which contain additives.

Misfiring is a general term that applies to a poor running engine. With misfiring, the ignition spark is not igniting the air/fuel mixture at the proper time. While other possible causes must be investigated, the spark plugs should be inspected first. Spark voltage should not reach ground before jumping across the gap at the tip of the spark plug. This leaves the air/fuel mixture unburned, causing misfiring. Pre-ignition misfiring occurs when the spark plug tip overheats, igniting the mixture before the spark jumps.

Carbon fouling of the spark plug is indicated by dry carbon deposits on the portion of the spark plug inside of the cylinder. Excess idling and driving at slower speeds under light engine loads can keep the spark plug temperatures so low that these deposits are not burned off. Rich fuels or poor ignition system output may also cause carbon fouling.

Oil fouling of the spark plug appears as wet oily deposits on the portion of the spark plug inside of the cylinder. This may be caused by the following conditions

1. Oil getting past worn piston rings
2. Breaking in a new or recently overhauled engine

Deposit fouling of the spark plug occurs when the normal reddish brown, yellow, or white deposits of combustion by-products become sufficient enough to cause misfiring. In some cases, these deposits melt and form a shiny glaze on the insulator around the center electrode. If the fouling is found only in one or two of the cylinders, valve stem clearances or the intake valve seals may be allowing excess lubricating oil to enter the cylinder, particularly if the deposits are heavier on the intake valve side of the spark plug.

Excess gap means that the air space between the center and side electrodes at the bottom of the spark plug is too wide for consistent firing. This may be due to improper gap adjustment or to excess wear of the electrodes during use. A gap that is too small may cause idling instability. Excess gap wear might indicate vehicle operation at continual high speeds or with high engine loads. This causes the spark plugs to run too hot. Excessively lean fuel may also cause the wear.

Improper torque or seating can cause a spark plug to run hot, eventually leading to excess gap wear. In extreme cases, an overtightened or under-tightened spark plug can cause exhaust blow-by. The cylinder head seats must make good contact for sufficient heat transfer and spark plug cooling. Dirty or damaged threads in the head or on the spark plug can keep the spark plug from seating even though the proper torque is applied. Once the spark plugs are properly seated, tighten the spark plugs properly.

Cracked or broken insulators and insulator tips may be the result of improper installation or heat shock. Heat shock is a rapid increase in the insulator tip temperature which causes the insulator material to crack. The upper insulators can be broken when a poorly-fitting tool is used during servicing, or when the spark plug is hit from the outside. Cracks in the upper insulator may be inside the shell or invisible. The breakage may not cause problems until oil or water penetrates the crack later. Heat shock breakage in the lower insulator tip generally occurs during severe engine operating conditions such as higher RPM or heavy loading. Over advanced timing or low grade fuels may also cause heat shock breakage. Always replace spark plugs with broken or cracked insulators.

Damage during gapping can occur when the tool is pushed against the center electrode or the surrounding insulator, causing the insulator to crack. When gapping a spark plug, bend only the outside electrode. Keep tools free of any other parts.

Spark plugs with less than the recommended amount of service can sometimes be cleaned and re-gapped, then returned to service. If there is any doubt about the serviceability of a spark plug, replace the spark plug.

1. Turn the ignition OFF.
2. Remove the ignition coil.
3. Use compressed air in order to remove debris from the spark plug cavity.
4. Remove the spark plug.

1. Ensure that the spark plug gap is equivalent to the spark plug gap specification. Refer to «Ignition System Specifications»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction__ignition-system-specifications) .
2. Install the spark plug and tighten to 20 N.m (15 lb ft).
3. Install the ignition coil.

1. Turn the ignition OFF.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
3. Remove the exhaust manifold heat shield to obtain access.
4. Disconnect the crankshaft position (CKP) electrical connector (3).
5. Remove the crankshaft sensor bolt.
6. Remove the crankshaft sensor.

1. Install the crankshaft position sensor.
2. Install the crankshaft position sensor bolt and tighten to 10 N.m (89 lb in).
3. Connect the CKP electrical connector (3).
4. Install the exhaust manifold heat shield and tighten to 10 N.m (89 lb in).
5. Lower the vehicle.

1. Turn the ignition OFF.
2. Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access.
3. Remove the camshaft position (CMP) sensor electrical connector.
4. Remove the CMP sensor bolt.
5. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt and tighten to 10 N.m (89 lb in).
3. Install the CMP sensor electrical connector.
4. Install the power steering fluid reservoir.

1. Turn the ignition OFF.
2. Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access.
3. Remove the camshaft position (CMP) sensor electrical connector.
4. Remove the CMP sensor bolt.
5. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt and tighten to 10 N.m (89 lb in).
3. Install the CMP sensor electrical connector.
4. Install the power steering fluid reservoir.

1. Turn the ignition OFF.
2. Remove the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Disconnect the camshaft position (CMP) sensor electrical connector.
4. Remove the CMP sensor bolt.
5. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt and tighten to 10 N.m (89 lb in).
3. Connect the CMP sensor electrical connector.
4. Install the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

1. Turn the ignition OFF.
2. Remove the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Disconnect the camshaft position (CMP) sensor electrical connector.
4. Remove the CMP sensor bolt.
5. Remove the CMP sensor.

1. Install the CMP sensor.
2. Install the CMP sensor bolt and tighten to 10 N.m (89 lb in).
3. Connect the CMP sensor electrical connector.
4. Install the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

1. Turn the ignition OFF.
2. Remove the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Disconnect the camshaft position (CMP) actuator valve electrical connector.
4. Remove the CMP actuator valve bolt.
5. Remove the CMP actuator valve.
6. Inspect the CMP actuator valve seal for damage. Replace the seal if necessary.

1. Inspect the CMP actuator valve seal for damage. Replace the seal if necessary.
2. Install the CMP actuator valve.
3. Install the CMP actuator valve bolt and tighten to 10 N.m (89 lb in).
4. Connect the CMP actuator valve electrical connector.
5. Install the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

1. Turn the ignition OFF.
2. Remove the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Disconnect the camshaft position (CMP) actuator valve electrical connector.
4. Remove the CMP actuator valve bolt.
5. Remove the CMP actuator valve.
6. Inspect the CMP actuator valve seal for damage. Replace the seal if necessary.

1. Inspect the CMP actuator valve seal for damage. Replace the seal if necessary.
2. Install the CMP actuator valve.
3. Install the CMP actuator valve bolt and tighten to 10 N.m (89 lb in).
4. Connect the CMP valve electrical connector.
5. Install the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

1. Turn the ignition OFF.
2. Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access.
3. Remove the camshaft position (CMP) actuator valve electrical connector.
4. Remove the CMP actuator valve bolt.
5. Remove the CMP actuator valve.
6. Inspect the CMP actuator valve seal for damage and replace as necessary.

1. Inspect the CMP actuator valve seal for damage. Replace the seal if necessary.
2. Install the CMP actuator valve.
3. Install the CMP actuator valve bolt and tighten to 10 N.m (89 lb in).
4. Install the CMP actuator valve electrical connector.
5. Install the power steering fluid reservoir.

1. Turn the ignition OFF.
2. Remove the power steering fluid reservoir bolts and reposition the power steering fluid reservoir in order to provide access.
3. Remove the camshaft position (CMP) actuator valve electrical connector.
4. Remove the CMP actuator valve bolt.
5. Remove the CMP actuator valve.
6. Inspect the CMP actuator valve seal for damage and replace as necessary.

1. Inspect the CMP actuator valve seal for damage. Replace the seal if necessary.
2. Install the CMP actuator valve.
3. Install the CMP actuator valve bolt and tighten to 10 N.m (89 lb in).
4. Install the CMP actuator valve electrical connector.
5. Install the power steering fluid reservoir.

1. Turn the ignition OFF.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
3. Reposition the wiring harness heat shield to obtain access.
4. Remove the knock sensor (KS) electrical connector.
5. Remove the KS bolt.
6. Remove the KS.

1. Install the KS.
2. Install the KS bolt and tighten to 23 N.m (17 lb ft).
3. Install the KS electrical connector.
4. Install the wiring harness heat shield to the original position.
5. Lower the vehicle.

1. Turn the ignition OFF.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
3. Remove the wiring harness heat shield from the oil level indicator tube to gain access.
4. Remove the knock sensor (KS) electrical connector.
5. Remove the KS bolt.
6. Remove the KS.

1. Install the KS.
2. Install the KS bolt and tighten to 23 N.m (17 lb ft).
3. Install the KS electrical connector.
4. Install the wiring harness heat shield to the oil level indicator tube.
5. Lower the vehicle.

1. Remove the upper intake manifold with the lower intake manifold.
2. Remove the intake manifold runner control solenoid bolts.
3. Remove the intake manifold runner control solenoid.

1. Install the intake manifold runner control solenoid.
2. Install the intake manifold runner control solenoid bolts and tighten to 10 N.m (89 lb in).
3. Install the upper intake manifold.

1. Remove the air cleaner intake duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
2. Loosen the air cleaner cover screws.
3. Open the air cleaner cover and remove the air cleaner element.

1. Install the air cleaner element and close the air cleaner cover.
2. Install the air cleaner cover screws and tighten to 8 N.m (71 lb in).
3. Install the air cleaner intake duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Turn the ignition OFF.
2. Remove the air cleaner intake duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .
3. Disconnect the mass air flow (MAF) electrical connector.
4. Remove the air cleaner bolts.
5. Remove the air cleaner.

1. Install the air cleaner.
2. Install the air cleaner bolts and tighten to 9 N.m (78 lb in).
3. Connect the MAF electrical connector.
4. Install the air cleaner intake duct. Refer to «Air Cleaner Inlet Duct Replacement»(/cadillac/sts/i-2007-2011/remont/testing-diagnostics/#engine-controls-and-fuel-36l-introduction) .

1. Turn the ignition OFF.
2. Remove the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .
3. Remove the positive crankcase ventilation (PCV) hose from the air cleaner duct resonator.
4. Loosen the air cleaner duct clamps.
5. Remove the air cleaner duct.

1. Install the air cleaner intake duct.
2. Install the PCV hose to the intake duct resonator.
3. Tighten the air cleaner duct clamps and tighten to 4 N.m (35 lb in).
4. Install the front compartment sight shields as necessary. Refer to «Front Compartment Sight Shields Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-body-panels/#bolted-exterior-body-panels-and-closures) .

Air Intake System Description

The MAF sensor measures the amount of air coming into the engine. This direct airflow measurement is more accurate than the calculated airflow information obtained from the other sensor inputs. The MAF sensor also houses an integrated intake air temperature (IAT) sensor. The MAF sensor uses the following circuits

1. An ignition voltage circuit
2. A signal circuit
3. A ground circuit
4. An IAT signal circuit
5. An IAT low reference circuit

The MAF sensor that is used on this vehicle is a hot film type and is used in order to measure the air flow rate. The air flow through the sensor passes over a temperature sensor, is then heated, and then passes over another temperature sensor. The difference in air temperature before and after the heater is measured. The air temperature difference is proportional to the amount of air flow. This air temperature difference also allow for determination of whether the air is flowing in the forward or reverse directions. As the air flow increases the delta temperature between the two sensors increases. The MAF sensor converts the temperature difference into a frequency signal that the ECM monitors. The ECM calculates the air flow based on this signal.

The ECM monitors the MAF sensor signal frequency and can determine if the sensor signal is too low or too high. The ECM can also detect airflow that is inappropriate for a given operating condition based on the signal frequency.

The scan tool displays the MAF sensor value in grams per second (g/s) and hertz (Hz). Values should change rather quickly on acceleration, but should remain fairly stable at any given engine speed. If the ECM detects a condition with the MAF sensor circuits, the following DTCs set

1. P0100 Mass Air Flow (MAF) Sensor Circuit
2. P0101 Mass Air Flow (MAF) Sensor Performance
3. P0102 Mass Air Flow (MAF) Sensor Circuit Low Voltage
4. P0103 Mass Air Flow (MAF) Sensor Circuit High Voltage

Scheme 20

The camshaft actuator system enables the engine control module (ECM) to change camshaft timing of all 4 camshafts while the engine is operating. The CMP actuator assembly (15) varies the camshaft position in response to directional changes in oil pressure. The CMP actuator solenoid valve controls the oil pressure that is applied to advance or retard a camshaft. Modifying camshaft timing under changing engine demand provides better balance between the following performance concerns

1. Engine power output
2. Fuel economy
3. Lower tailpipe emissions

The CMP actuator solenoid valve (7) is controlled by the ECM. The crankshaft position (CKP) sensor and the CMP sensors are used to monitor changes in camshaft positions. The ECM uses the following information in order to calculate the desired camshaft positions

1. The engine coolant temperature (ECT) sensor
2. The calculated engine oil temperature (EOT)
3. The mass air flow (MAF) sensor
4. The throttle position (TP) sensor
5. The vehicle speed sensor (VSS)
6. The volumetric efficiency

Operation

The CMP actuator assembly has an outer housing that is driven by an engine timing chain. Inside the assembly is a rotor with fixed vanes that is attached to the camshaft. Oil pressure that is applied to the fixed vanes will rotate a specific camshaft in relationship to the crankshaft. The movement of the intake camshafts will advance the intake valve timing up to a maximum of 50 crankshaft degrees. The movement of the exhaust camshafts will retard the exhaust valve timing up to a maximum of 50 crankshaft degrees. When oil pressure is applied to the return side of the vanes, the camshafts will return to 0 crankshaft degrees, or top dead center (TDC). The CMP actuator solenoid valve directs the oil flow that controls the camshaft movement. The ECM commands the CMP solenoid to move the solenoid plunger and spool valve until oil flows from the advance passage (11). Oil flowing thru the CMP actuator assembly from the CMP solenoid advance passage applies pressure to the advance side of the vanes in the CMP actuator assembly. When the camshaft position is retarded, the CMP actuator solenoid valve directs oil to flow into the CMP actuator assembly from the retard passage (3). The ECM can also command the CMP actuator solenoid valve to stop oil flow from both passages in order to hold the current camshaft position.

The ECM operates the CMP actuator solenoid valve by pulse width modulation (PWM) of the solenoid coil. The higher the PWM duty cycle, the larger the change in camshaft timing. The CMP actuator assembly also contains a lock pin (14) that prevents movement between the outer housing and the rotor vane assembly. The lock pin is released by oil pressure before any movement in the CMP actuator assembly takes place. The ECM is continuously comparing CMP sensor inputs with CKP sensor input in order to monitor camshaft position and detect any system malfunctions. If a condition exists in either the intake or exhaust camshaft actuator system, the opposite bank, intake or exhaust, camshaft actuator will default to 0 crankshaft degrees.

CMP Actuator System Operation

Electronic Ignition (EI) System Description

The electronic ignition (EI) system produces and controls a high-energy secondary spark. This spark is used to ignite the compressed air/fuel mixture at precisely the correct time. This provides optimal performance, fuel economy, and control of exhaust emissions. This ignition system uses an individual coil for each cylinder. The ignition coils are mounted in the center of each camshaft cover with short integrated boots connecting the coils to the spark plugs. The driver modules within each ignition coil are commanded ON/OFF by the engine control module (ECM). The ECM primarily uses engine speed, the MAF sensor signal, and position information from the crankshaft position (CKP) and the camshaft position (CMP) sensors. This controls the sequence, dwell, and timing of the spark. The EI system consists of the following components

Crankshaft Position (CKP) Sensor

The crankshaft position (CKP) sensor works in conjunction with a 58 tooth reluctor wheel on the crankshaft. The engine control module (ECM) monitors the voltage frequency on the CKP sensor signal circuit. As each reluctor wheel tooth rotates past the sensor, the sensor creates a digital ON/OFF pulse. This digital signal is processed by the ECM. The reluctor wheel teeth are 6 degrees apart. Having only 58 teeth leaves a 12 degree span that is uncut. This creates a signature pattern that enables the ECM to determine the CKP. The ECM uses the signal to determine which pair of cylinders is approaching top dead center based on the CKP signal alone. The camshaft position (CMP) sensor signals are used in order to determine which of these 2 cylinders is on a firing stroke, and which is on the exhaust stroke. The ECM uses this to properly synchronize the ignition system, the fuel injectors, and the knock control. This sensor is also used in order to detect misfire. The CKP sensor uses the following circuits

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

Camshaft Position (CMP) Sensor

This engine uses 4 camshaft position (CMP) sensors, one for each camshaft. The CMP sensor signals are a digital ON/OFF pulse, output 4 times per revolution of the camshaft. The CMP sensor does not directly affect the operation of the ignition system. The CMP sensor information is used by the engine control module (ECM) to determine the position of the 4 camshafts relative to the crankshaft position. By monitoring the CMP and crankshaft position (CKP) signals the ECM can accurately time the operation of the fuel injectors. The ECM supplies the CMP sensor with a 5-volt reference circuit and a low reference circuit. The CMP sensor signals are an input to the ECM. These signals are also used to detect camshaft alignment with the crankshaft.

Ignition Coils

Each ignition coil contains a solid state driver module as its primary element. The engine control module (ECM) signals the coil driver to initiate a firing event by applying ignition control (IC) circuit voltage for the appropriate time, or dwell. When the voltage is removed the coil fires the spark plug. The ignition coils use the following circuits

1. An ignition voltage supply circuit
2. An IC circuit
3. Two ground circuits

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 components

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 transmission gear position or range information sensors
7. The engine knock sensors (KS)
8. Ambient pressure sensor (BARO)

Scheme 21

The engine control module (ECM) interacts with many more emission related components and systems, and monitors 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 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 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.

Theft Deterrent System Frequency Code Programming

This vehicle is equipped with a theft deterrent system which interfaces with the ECM. If the ECM is replaced, program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle. The vehicle will not start until this procedure is completed.

KS Module

The ECM employs an internal integrated circuit to continuously monitor the knock control evaluation circuit. The knock sensor (KS) module contains the circuitry that allows the ECM to utilize the knock sensor (KS) signals and diagnose the KS sensors and circuitry. If the ECM detects a fault in the ability of the KS module to sample these signals, a DTC sets.

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 ECM and illuminates when the ECM detects a condition that affects the vehicle emissions.

ECM Service Precautions

The 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 MIL and stores a DTC that is associated with the condition.

Aftermarket (Add-On) Electrical And Vacuum Equipment

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

Note. In order to prevent possible electrostatic discharge damage to the ECM, DO NOT touch the connector pins on the ECM.

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. By comparison, it takes as much as 4,000 volts for a person to even feel the zap of a static discharge.

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 left 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

Note. This inspection is very important and must be done carefully and thoroughly.

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

Basic Knowledge Required

A basic understanding of hand tools is necessary in order to effectively use this section of the Service Manual.

You must be familiar with some of the basics of engine operation and electrical diagnosis in order to use this section of the service manual.

1. Basic electrical circuits-You should have an understanding of basic electricity and know the meaning of voltage (volts), current (amps), and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire, and you should be able to identify a shorted or open circuit by using a DMM. You should be able to read and understand a wiring diagram.
2. Use of digital multimeter-You should be familiar with the DMM, particularly the essential tool. You should be able to use the meter in order to measure the voltage (volts), the resistance (ohms), the current (amps), intermittents (min/max), and frequency (Hertz).
3. Use of circuit testing tools-You should not use a test lamp to diagnose the engine controls system unless you are specifically instructed to do so. You should know how to the use jumper wires in order to test the components and allow the DMM readings without damaging the terminals. You should know how to use the J 35616: GM Approved Terminal Test Kit connector test adapter kit and use the kit whenever the diagnostic procedures call for front probing any connector.

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 valve to 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 valve ON, open, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent valve OFF, open, fresh air will be drawn through the valve and 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 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 blockages in the EVAP system. The control module will command the EVAP vent valve ON, closed, and command the EVAP purge valve ON, open, with the engine running, allowing engine 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. The control module then commands the EVAP purge valve OFF, closed, sealing the system and monitors the vacuum level for decay. If the control module does not detect that the predetermined vacuum level was achieved, or the vacuum decay rate is more than a calibrated level on 2 consecutive tests, DTC P0455 sets.

Small Leak Test

The engine off natural vacuum, (EONV), diagnostic is the small leak detection diagnostic for the EVAP system. The EONV diagnostic monitors the EVAP system pressure or vacuum with the key OFF. The EONV utilizes the temperature changes and the resulting naturally occurring vacuum or pressure in the fuel tank immediately following a drive cycle. When the vehicle is driven, the temperature in the fuel tank rises. When the vehicle is parked with the engine OFF and key OFF, the temperature in the fuel tank will continue to rise for a period of time, and then begin to decrease. The EONV diagnostic relies on this temperature change, and the corresponding pressure change 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 EVAP system is sealed a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, 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 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 valve ON, open; and commanding the EVAP vent valve OFF, open; and monitoring the FTP sensor for an increase in vacuum. If vacuum increases more than a calibrated value, DTC P0446 sets.

Purge Valve Leak Test

If the EVAP purge 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 valve OFF, closed; and vent valve ON, closed; sealing the system, and monitoring the FTP for an increase in vacuum. If the control module detects that EVAP system vacuum increases above a calibrated value, DTC P0496 sets.

EVAP System Components

The 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 Valve

The EVAP purge valve controls the flow of vapors from the EVAP system to the intake manifold. 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 Valve

The EVAP vent valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module will command the valve closed during some EVAP tests, allowing the system to be tested for leaks.

Fuel Tank Pressure Sensor

The 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. As FTP increases, FTP sensor voltage decreases, high pressure = low voltage. As FTP decreases, FTP voltage increases, low pressure or vacuum = high voltage.

Fuel System Overview

The fuel tank stores the fuel supply. The fuel pump module, located in the fuel tank, supplies fuel through the fuel feed pipe to the high pressure fuel pump. The high pressure fuel pump supplies fuel to a variable-pressure fuel rail. Fuel enters the combustion chamber through precision multi-hole fuel injectors. The high pressure fuel pump, fuel rail pressure, fuel injection timing, and injection duration are controlled by the engine control module (ECM).

Fuel Tank

The fuel storage tank is made of high density polyethylene. The fuel storage tank is held in place by 2 metal straps that are attached to the under body of the vehicle. The tank shape includes a sump in order to maintain a constant supply of fuel around the fuel pump strainer during low fuel conditions or during aggressive maneuvers.

The fuel tank also contains a fuel vapor vent valve with a roll-over protection. The vent valve also features a 2-phase vent calibration which increases the fuel vapor flow to the canister when the operating temperatures increase the tank pressure beyond an established threshold.

On-Board Refueling Vapor Recovery (ORVR) System

The on-board refueling vapor recovery (ORVR) system is an on-board vehicle system to recover fuel vapors during the vehicle refueling operation. The flow of liquid fuel down to the fuel tank filler neck provides a liquid seal. The purpose of ORVR is to prevent refueling vapor from exiting the fuel tank filler neck. The ORVR components are listed below, with a brief description of their operation

1. The fuel tank-The fuel tank contains the modular fuel sender, the fuel limiter vent valve (FLVV), and 1 rollover valve.
2. The fuel filler pipe-The fuel filler pipe carries fuel from the fuel nozzle to the fuel tank.
3. The evaporative emission (EVAP) canister-The EVAP canister receives refueling vapor from the fuel system, stores the vapor, and releases the vapor to the engine upon demand.
4. The vapor lines-The vapor lines transport fuel vapor from the tank assembly to the EVAP canister and engine.
5. The check valve-The check valve limits fuel spit-back from the fuel tank during the refueling operation by allowing fuel flow only into the fuel tank. The check valve is located at the bottom of the fuel filler pipe.
6. The modular fuel sender assembly-The modular fuel sender assembly pumps fuel to the engine from the fuel tank.
7. The fuel tank pressure (FTP) sensor is located on top of the fuel tank vapor dome.
8. The FLVV-The FLVV acts as a shut-off valve. The FLVV is located in the fuel tank. This valve has the following functions: Controlling the fuel tank fill level by closing the primary vent from the fuel tank Preventing fuel from exiting the fuel tank via the vapor line to the canister Providing fuel spillage protection in the event of a vehicle rollover by closing the vapor path from the tank to the engine
9. The pressure vacuum relief valve-The pressure vacuum relief valve provides venting of excessive fuel tank pressure and vacuum. The valve is located in the fuel fill cap.
10. The vapor recirculation line-The vapor recirculation line is used to transport vapor from the fuel tank to the top of the fill pipe during refueling to reduce vapor loading to the enhanced EVAP canister.

Fuel Tank Filler Pipe

In order to prevent refueling with leaded fuel, the fuel filler pipe has a built-in restrictor and a deflector. The opening in the restrictor will accept only the smaller unleaded gasoline fuel nozzle which must be fully inserted in order to bypass the deflector. The tank is vented during filling by an internal vent tube inside of the filler pipe.

Scheme 22

The fuel tank filler pipe is equipped with a turn to vent screw on the type cap which incorporates a ratchet action in order to prevent over-tightening.

The turn to vent feature allows the fuel tank pressure relief prior to removal. Instructions for proper use are imprinted on the cap cover. A vacuum safety relief valve is incorporated into this cap.

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The modular fuel sender assembly mounts to the threaded opening of the plastic fuel tank with a seal and a retainer ring. The reservoir, containing the exterior inlet strainer, the electric fuel pump and the pump strainer, maintains contact with the tank bottom. This design provides

1. Optimum fuel level in the integral fuel reservoir during all fuel tank levels and during driving conditions
2. An improved tank fuel level measuring accuracy
3. An improved coarse straining and added pump inlet filtering
4. More extensive internal fuel pump isolation for noiseless operation

The modular fuel sender assembly maintains an optimum fuel level in the reservoir (bucket). The fuel entering the reservoir is drawn in by the following components

1. The first stage of the fuel pump through the external strainer and/or
2. The secondary umbrella valve or
3. The return fuel line, whenever the level of fuel is below the top of the reservoir

Fuel Pump

The electric fuel pump is a turbine pump which is located inside of the modular fuel sender. The electric fuel pump operation is controlled by the engine control module (ECM) through the fuel pump relay.

Fuel Sender Strainers

The strainers act as a coarse filter to perform the following functions

1. Filter contaminants
2. Separate water from fuel
3. Provide a wicking action that helps draw fuel into the fuel pump

Fuel stoppage at the strainer indicates that the fuel tank contains an abnormal amount of sediment or water. Therefore, the fuel tank will need to be removed and cleaned, and the filter strainer should be replaced.

Scheme 24

The fuel filter is located on the fuel feed pipe, between the fuel pump and the fuel rail. The electric fuel pump supplies fuel through the in-line fuel filter to the fuel injection system. The fuel pressure regulator keeps the fuel available to the fuel injectors at a regulated pressure. Unused fuel is returned from the fuel filter to the fuel tank by a separate fuel return pipe. The paper filter element (2) traps particles in the fuel that may damage the fuel injection system. The filter housing (1) is made to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There is no service interval for fuel filter replacement. Replace a restricted fuel filter.

EVAP Lines and Hoses

The EVAP line extends from the fuel tank vent valve to the EVAP canister and into the engine compartment. The EVAP line is made of nylon and connects to the EVAP canister with a quick connect fitting.

Scheme 25

The fuel pressure regulator attaches to the fuel return pipe on the fuel sender assembly. The fuel pressure regulator is a diaphragm-operated relief valve. A software bias compensates the injector on-time because the fuel pressure regulator is not referenced to manifold vacuum. The injector pulse width varies with the signal from the mass air flow (MAF)/intake air temperature (IAT) sensor.

With the engine running at idle, the system fuel pressure at the pressure test connection should be between 380-410 kPa (55-60 psi). With the system pressurized and the pump OFF the pressure should stabilize and hold. If the pressure regulator supplies a fuel pressure which is too low or too high, a driveability condition will result.

Scheme 26

The high pressure fuel pump (9) is a mechanical one cylinder design driven by an eccentric on the exhaust camshaft (1) of bank 2. High pressure fuel is regulated by the fuel rail pressure (FRP) regulator, which is a part of the high pressure fuel pump. The FRP regulator is a magnetic actuator which controls the inlet valve of the high pressure pump. The ECM provides battery voltage on the actuator high circuit and ground on the actuator low reference circuit. Both circuits are controlled by the ECM. When the ECM deactivates the FRP regulator, both circuits are disabled and the inlet valve is held open with spring pressure. When the ECM activates the FRP regualtor, the low circuit driver connects the low reference circuit to ground and the high circuit driver pulse-width modulates (PWM) the high circuit. The ECM uses the camshaft and crankshaft position sensor inputs to synchronize the FRP regulator with the position of the eccentric on the camshaft. The ECM regulates fuel pressure by adjusting the portion of each pump stroke that provides fuel to the rail. The high pressure fuel pump also contains an integrated pressure relief valve.

Fuel Rail Assembly

The fuel rail assembly (3) attaches to each cylinder head. The fuel rail distributes high pressure fuel to the fuel injectors. The fuel rail assembly consists of the following components

1. Six fuel injectors
2. A fuel rail pressure (FRP) sensor

Fuel Injectors

The fuel injection system is a high pressure, direct injection, returnless on-demand design. The fuel injectors (6) are mounted in the cylinder head beneath the intake ports and spray fuel directly into the combustion chamber. Direct injection requires high fuel pressure due to the fuel injector's location in the combustion chamber. Fuel pressure must be higher than compression pressure requiring a high pressure fuel pump. The fuel injectors also require more electrical power due to the high fuel pressure. The ECM supplies a separate high voltage supply circuit and a driver circuit for each fuel injector.

The fuel injector assembly is an inside opening electrical magnetic injector. The injector has six precision machined holes that generate a cone shaped oval spray pattern. The fuel injector has a slim extended tip in order to allow a sufficient cooling jacket in the cylinder head.

The fuel injectors will cause various driveability conditions if the following conditions occur

1. If the injectors will not open
2. If the injectors are stuck open
3. If the injectors are leaking
4. If the injectors have a low coil resistance

Fuel Rail Fuel Pressure Sensor

The fuel rail pressure sensor (4) detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 volt reference voltage on the 5 volt reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the FRP sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

Fuel Pump Relay

The fuel pump relay allows the ECM to energize the fuel pump. The ECM supplies B+ to the fuel pump relay which enables the fuel pump whenever the crankshaft position (CKP) sensor pulses are detected.

Engine Fueling

The engine is fueled by six individual injectors, one for each cylinder, that are controlled by the ECM. The ECM controls each injector by energizing the injector coil for a brief period once every other engine revolution. The length of this brief period, or pulse, is carefully calculated by the ECM to deliver the correct amount of fuel for proper driveability and emissions control. The period of time when the injector is energized is called the pulse width and is measured in milliseconds, thousandths of a second.

While the engine is running, the ECM is constantly monitoring the inputs and recalculating the appropriate pulse width for each injector. The pulse width calculation is based on the injector flow rate, mass of fuel the energized injector will pass per unit of time, the desired air/fuel ratio, and actual air mass in each cylinder and is adjusted for battery voltage, short term, and long term fuel trim. The calculated pulse is timed to occur as each cylinders intake valves are closing to attain largest duration and most vaporization.

Fueling during a crank is slightly different than fueling during an engine run. As the engine begins to turn, a prime pulse may be injected to speed starting. As soon as the ECM can determine where in the firing order the engine is, the ECM begins pulsing the injectors. The pulse width during the crank is based on the coolant temperature and the engine load.

The fueling system has several automatic adjustments in order to compensate for the differences in the fuel system hardware, the driving conditions, the fuel used, and the engine aging. The basis for the fuel control is the pulse width calculation that is described above. Included in this calculation are an adjustment for the battery voltage, the short term fuel trim, and the long term fuel trim. The battery voltage adjustment is necessary since the changes in the voltage across the injector affect the injector flow rate. The short term and the long term fuel trims are fine and coarse adjustments to the pulse width that are designed in order to maximize the driveability and emissions control. These fuel trims are based on the feedback from the oxygen sensors in the exhaust stream and are only used when the fuel control system is in a Closed Loop operation.

Under certain conditions, the fueling system will turn OFF the injectors for a period of time. This is referred to as fuel shut-off. Fuel shut-off is used in order to improve traction, save fuel, improve emissions, and protect the vehicle under certain extreme or abusive conditions.

In case of a major internal problem, the ECM may be able to use a back-up fuel strategy for limp in mode that will run the engine until service can be performed.

Sequential Fuel Injection (SFI)

The ECM controls the fuel injectors based on information that the ECM receives from several information sensors. Each injector is fired individually in the engine firing order, which is called sequential fuel injection. This allows precise fuel metering to each cylinder and improves the driveability under all of the driving conditions.

The ECM has several operating modes for fuel control, depending on the information that has been received from the sensors.

Starting Mode

When the ECM detects reference pulses from the CKP sensor, the ECM will enable the fuel pump. The fuel pump runs and builds up pressure in the fuel system. The ECM then monitors the MAF, IAT, engine coolant temperature (ECT), and the throttle position (TP) sensor signal in order to determine the required injector pulse width for starting.

Clear Flood Mode

If the engine is flooded with fuel during starting and will not start, the Clear Flood Mode can be manually selected. To select Clear Flood Mode, push the accelerator to wide open throttle (WOT). With this signal, the ECM will completely turn OFF the injectors and will maintain this stage as long as the ECM indicates a WOT condition with engine speed below 1,000 RPM.

Run Mode

The Run Mode has 2 conditions: Open Loop operation and Closed Loop operation. When the engine is first started and the engine speed is above 480 RPM, the system goes into Open Loop operation. In Open Loop operation, the ECM ignores the signals from the oxygen sensors and calculates the required injector pulse width based primarily on inputs from the MAF, IAT and ECT sensors.

In Closed Loop, the ECM adjusts the calculated injector pulse width for each bank of injectors based on the signals from each oxygen sensor.

Acceleration Mode

The ECM monitors the changes in the TP and the MAF sensor signals in order to determine when the vehicle is being accelerated. The ECM will then increase the injector pulse width in order to provide more fuel for improved performance.

Deceleration Mode

The ECM monitors changes in TP and MAF sensor signals to determine when the vehicle is being decelerated. The ECM will then decrease injector pulse width or even shut OFF injectors for short periods to reduce exhaust emissions, and for better (engine braking) deceleration.

Battery Voltage Correction Mode

The ECM can compensate in order to maintain acceptable vehicle driveability when the ECM sees a low battery voltage condition. The ECM compensates by performing the following functions

1. Increasing the injector pulse width in order to maintain the proper amount of fuel being delivered
2. Increasing the idle speed to increase the generator output

Fuel Shut-Off Mode

The ECM has the ability to completely turn OFF all of the injectors or selectively turn OFF some of the injectors when certain conditions are met. These fuel shut-off modes allow the ECM to protect the engine from damage and also to improve the vehicles driveability.

The ECM will disable all of the six injectors under the following conditions

1. Ignition OFF-Prevents engine run-on
2. Ignition ON but no CKP signal-Prevents flooding or backfiring
3. A high engine speed-Above the red line
4. A high vehicle speed-Above the rated tire speed
5. Closed throttle cast down-Reduces the emissions and increases engine braking.

The ECM will selectively disable the injectors under the following conditions

1. The torque management enabled-Transmission shifts or abusive maneuvers.
2. The traction control enabled-In conjunction with the front brakes applying

Knock Sensor (KS) System Description

You can diagnose all of the sensors and most of the input circuits with a scan tool. Within this section is a short description of how to use a scan tool wherever possible to diagnose these circuits. You can also use the scan tool to compare the values for an engine that is running normally with the engine you are diagnosing.

The knock sensor (KS) system detects engine knocking or pinging. The ECM will retard the spark timing based on the signals from the KS system. The KS produce an AC voltage that is sent to the engine control module (ECM). The amount of the AC voltage produced is proportional to the amount of knock.

The ECM monitors the voltage of the sensors after each cylinder has fired.

If knock occurs in any of the cylinders, the ignition will be retarded for that particular cylinder. If the knocking then stops, the ignition will be restored to what it was before in steps.

Should knocking continue in the same cylinder in spite of the ignition being retarded, the ECM will retard the ignition an additional steps, and so on, up to a maximum of 12 degrees of retard. The ignition will also be retarded at high ambient temperatures in order to counteract knocking tendencies provoked by high intake air temperatures.

Should either bank 1 or bank 2 sensor fail to work, or should an internal circuit problem occur, the ignition timing will then use a default strategy. The default strategy will retard the ignition the maximum allowed amount to protect the engine from possible damage.

Throttle Actuator Control (TAC) System Description

The throttle actuator control (TAC) system is used to improve emissions, fuel economy, and driveability. The TAC system eliminates the mechanical link between the accelerator pedal and the throttle plate. The TAC system eliminates the need for a cruise control module and idle air control motor. The following is a list of TAC system components

1. The accelerator pedal assembly includes the following components: The accelerator pedal The accelerator pedal position (APP) sensor 1 The APP sensor 2
2. The throttle body assembly includes the following components: The throttle position (TP) sensor 1 The TP sensor 2 The throttle actuator motor The throttle plate
3. The engine control module (ECM)

The ECM monitors the driver demand for acceleration with 2 APP sensors. The APP sensor 1 signal voltage range is from about 0.98-4.16 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The APP sensor 2 range is from about 0.49-2.08 volts as the accelerator pedal is moved from the rest pedal position to the full pedal travel position. The ECM processes this information along with other sensor inputs to command the throttle plate to a certain position.

The throttle plate is controlled with a direct current motor called a throttle actuator control motor. The ECM can move this motor in the forward or reverse direction by controlling battery voltage and/or ground to 2 internal drivers. The throttle plate is held at a 7 percent rest position using a constant force return spring. This spring holds the throttle plate to the rest position when there is no current flowing to the actuator motor.

The ECM monitors the throttle plate angle with 2 TP sensors. The TP sensor 1 signal voltage range is from about 4.86-0.86 volts as the throttle plate is moved from 0 percent to wide open throttle (WOT). The TP sensor 2 voltage range is from about 0.82-4.14 volts as the throttle plate is moved from 0 percent to WOT.

The ECM performs diagnostics that monitor the voltage levels of both APP sensors, both TP sensors, and the throttle actuator control motor circuit. It also monitors the spring return rate of both return springs that are housed internal to the throttle body assembly. These diagnostics are performed at different times based on whether the engine is running, not running, or whether the ECM is currently in a throttle body relearn procedure.

Every ignition cycle, the ECM performs a quick throttle return spring test to make sure the throttle plate can return to the 7 percent rest position from the 0 percent position. This is to ensure that the throttle plate can be brought to the rest position in case of an actuator motor circuit failure. Observe, under cold conditions, the ECM commands the throttle plate to 7 percent with the ignition ON and the engine OFF to release any ice that may have formed on the throttle plate.

Throttle Body Relearn Procedure

The engine control module (ECM) stores values that include the lowest possible throttle position (TP) sensor positions-0 percent, the rest positions-7 percent, and the return rate of both springs. These values will only be erased or overwritten if the ECM is reprogrammed or if a throttle body relearn procedure is performed. Observe, if the battery is disconnected, the ECM will immediately perform a throttle body relearn procedure when the ignition is turned ON.

A throttle body relearn procedure is performed anytime the ignition is turned ON, with the engine OFF for longer than 29 seconds when the following conditions have been met

1. The engine speed is less than 40 RPM.
2. The vehicle speed is 0 km/h (0 mph).
3. The engine coolant temperature (ECT) is between 5-85°C (41-185°F).
4. The intake air temperature (IAT) is between than 5-60°C (41-140°F).
5. The accelerator pedal position (APP) sensor angle is less than 14.9 percent.
6. The ignition 1 voltage is more than 10 volts.

After 29 seconds, the ECM commands the throttle plate from the rest position to full closed, then to around 10 percent open. This procedure takes about 6-8 seconds. If any faults occur in the throttle actuator control (TAC) system, a DTC sets. At the start of this procedure, the scan tool TAC Learn Counter parameter should display 0, then count up to 11 after the procedure is completed. If the counter did not start at 0, or if the counter did not end at 11, a fault has occurred and a DTC should set.

TAC System Default Actions/Reduce Power Modes

There are 2 reduce power modes that the engine control module (ECM) can default to if an error is detected in the throttle actuator control (TAC) system. If an accelerator pedal position (APP) sensor 1 or APP sensor 2 circuit fault, throttle position (TP) sensor 2 circuit fault, or if a TP sensor 1 circuit fault is detected with some APP angle, the ECM goes into one of the 2 reduce power modes. In this mode, the engine torque is limited so that the vehicle cannot reach speeds of more than 100 km/h (60 mph). The ECM remains in this reduce power mode during the entire ignition cycle even if the fault is corrected.

If there is a condition with the throttle actuator control circuits, throttle actuator command vs actual position fault, return spring check fault, or a TP sensor 1 circuit fault, the ECM goes into the other reduce engine power mode. In this mode, the engine speed is limited to 2,500 RPM and the 3-6 fuel injectors are randomly turned OFF. At this time the Reduced Power indicator is commanded ON. The ECM remains in the reduce power mode during the entire ignition cycle even if the fault is corrected. Observe, if a TP sensor 1 or throttle actuator control circuit fault is present at the time the vehicle is at idle, with no accelerator pedal angle, the engine may stall.

Illustration Tool Number/Description CH 48027 Digital Pressure Gage CH 48096 EVAP Service Access Port Tool EL 39021-460 Fuel Injector Test Adapter EN 47909 Injector Bore and Sleeve Cleaning Kit EN 48266 Injector Seal Installer/Sizer EN 48896 HP Fuel Pump Installation Alignment Gage GE 41415-50 Fuel Tank Cap Adapter J 2619-01 Slide Hammer J 26792 HEI Spark Tester J 34730-405 Injector Test Lamp J 35616-A/B-8637 Connector Test Adapter Kit J 35616-200 Test Light - Probe Kit J 37088-A Fuel Line Disconnect Tool Set J 37281-A Injector Remover J 37287 Fuel Line Shut-Off Adapters J 38522 Variable Signal Generator J 39021 Fuel Injector Coil and Balance Test J 39021-210 Injector Selector Switch Box J 41413-200 Evaporative Emission System Tester (EEST) J 41413-300 EVAP Cap and Plug Kit J 41413-SPT High Intensity White Light J 42960-02 Fuel Flapper Door Holder J 43244 Relay Puller Pliers J 44175 Fuel Composition Tester J 44581 Fuel Line Disconnect Tool J 44602 Injector Test Adapter J 45004 Fuel Tank Drain Hose J 45747 Fuel Sender Lock Ring Wrench

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See also:
• Diagnostic System Check - Vehicle
• DTC P0008 or P0009
• DTC P0201-P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D (w/LLT)
• DTC P0856
• Battery Negative Cable Disconnection and Connection (Side Post)
• Control Module References
• Fastener Caution
• Cooling System Draining and Filling (GE 47716)
• Fuel Injector Sight Shield Replacement (LLT)
• Lifting and Jacking the Vehicle
• Oxygen Sensor Caution
• Component Fastener Tightening Caution
• Instrument Panel Insulator Panel Replacement - Left Side
• Disengaging Connectors Caution
• Gasoline/Gasoline Vapors Warning
• Electrical Center Identification Views
• Safety Glasses Warning
• Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Caution
• Relieving Fuel Pressure Warning
• Fuel Pipe Fitting Warning
• Rear Suspension Bracket Replacement
• Exhaust System Replacement
• Rear Propeller Shaft Replacement (AWD)
• Rear Frame Replacement
• Tire and Wheel Removal and Installation
• Cross Vehicle Brace Replacement
• Windshield Wiper Transmission Replacement
• Safety Glasses and Compressed Air Warning
• Clean, Dry, Low Pressure Gas Source Caution
• Air Cleaner Inlet Duct Replacement
• Fuel Pressure Relief (With High Pressure Pump - LLT)
• Ignition System Specifications