Engine Exhaust System Cadillac XLR I

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Exhaust System Connector End Views

Exhaust Tail Pipe Flow Control Module C1

Scheme 5

Exhaust System Connector End Views

Exhaust Tail Pipe Flow Control Module C2

Scheme 6

Exhaust System Connector End Views

Exhaust Tail Pipe Flow Control Valve Solenoid

Diagnostic Starting Point - Engine Exhaust

Begin the system diagnosis by reviewing the system Description and Operation. Reviewing the information will help you determine the correct symptom diagnostic procedure when a malfunction exists. It will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Engine Exhaust in order to identify the correct procedure for diagnosing the system.

Diagnostic Starting Point - Exhaust Flow Control System

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 diagnostic trouble codes (DTCs) and their status

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

Scan Tool Output Controls

Scan Tool Output Controls

Scan Tool Data List

Scan Tool Data List

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

DTC P166A

Circuit/System Description

Exhaust tail pipe flow valve control module receives throttle position sensor and RPM information via serial data from powertrain control module (PCM). The exhaust tail pipe flow valve control module uses this information to determine if to command exhaust tail pipe flow control valve solenoid ON or OFF. When commanded OFF the exhaust tail pipe flow control valve solenoid allows vacuum to flow to close exhaust valve.

Conditions for Running the DTC

1. The ignition is ON.
2. Ignition voltage is greater than 8 volts.

Conditions for Setting the DTC

1. Exhaust tail pipe flow valve control module detects short to voltage on exhaust valve solenoid supply voltage circuit.
2. Exhaust tail pipe flow valve control module detects short to ground on exhaust valve solenoid supply voltage circuit.

Action Taken When the DTC Sets

Exhaust flow control valve defaults to open.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool.

Reference Information

Schematic Reference

Exhaust System Schematics

Connector End View Reference

Exhaust System Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Scan Tool Reference

Scan Tool Data List for exhaust tail pipe flow valve control module

Circuit/System Testing

1. Ignition OFF, disconnect the exhaust tail pipe flow control valve solenoid connector.
2. Ignition ON, measure for 0 volts between the exhaust tail pipe flow control valve solenoid supply voltage circuit and ground. If over 0 volts, test for short to voltage in exhaust valve solenoid supply voltage circuit.
3. Ignition ON, use scan tool to command exhaust flow control relay ON, measure for 10 volts or above between the exhaust tail pipe flow control valve solenoid supply voltage circuit and ground. If under 10 volts, test for short to ground in exhaust valve solenoid supply voltage circuit.
4. If all circuits test normal replace the exhaust tail pipe flow valve control module.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for exhaust tail pipe flow valve control module replacement, setup, and programming

Symptoms - Engine Exhaust

1. Review the Exhaust System Description and Operation in order to familiarize yourself with the system functions. Refer to «Exhaust System Description»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__exhaust-system-description) .
2. All diagnostics on a vehicle should follow a logical process. Strategy Based Diagnostics is a uniform approach for repairing all systems. The diagnostic flow chart is the place to start when repairs are necessary and may always be used in order to resolve a system problem. For a detailed explanation, refer to «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) .

Visual/Physical Inspection

1. Inspect for aftermarket or non-OEM devices such as, but not limited too; tailpipe extensions, headers, and exhaust cutouts. This could affect the operation and proper performance of the exhaust system.
2. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, engine temperature, engine load, and frequency of concern.
3. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause any symptom.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating as designed.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. Loss of power - Refer to «Restricted Exhaust»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
2. Poor acceleration - Refer to «Restricted Exhaust»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
3. Poor fuel economy - Refer to «Restricted Exhaust»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
4. Excessive smoke - Refer to «Restricted Exhaust»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
5. Exhaust hissing noise - Refer to «Exhaust Leakage»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
6. Exhaust popping noise - Refer to «Exhaust Leakage»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
7. Exhaust rattle noise - Refer to «Exhaust Noise»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__exhaust-noise) .
8. Loud exhaust noise - Refer to «Exhaust Noise»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__exhaust-noise) .
9. Exhaust buzz, groan, hum noise - Refer to «Exhaust Noise»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__exhaust-noise) .

Diagnostic Aids

System diagnosis includes reviewing the system Exhaust Tail Pipe Flow Control System Description and Operation . Reviewing the information will help determine when a malfunction exists. It will also help to determine if the condition described by the customer is a normal system operation. Refer to Symptoms - Engine Exhaust in order to identify the correct procedure for diagnosing the system.

A scan tool can be used to command the vacuum solenoid On or Off.

1. Vacuum solenoid commanded OFF: Engine vacuum is blocked to the exhaust flow control valves mechanically by the position of the solenoid valve. Exhaust flow control valve vacuum diagrams are vented to the atmosphere mechanically due to the position of the solenoid valve. Exhaust flow control valves are OPEN. Exhaust gases flow through the least restrictive passage in the mufflers. Exhaust gases exit all muffler tail pipes.
2. Vacuum solenoid commanded ON: Engine vacuum is sent to the exhaust flow control valve. Both exhaust flow control valves CLOSE. Exhaust gases must flow through a more restrictive passage within the mufflers. Exhaust gases exit only the outboard tail pipe of each muffler.

Exhaust Tail Pipe Flow Valve Mechanical System Diagnosis

For dual exhaust systems a quick check of exhaust flow will help determine which side of the exhaust system is restricted. The side that has less exhaust flow is the side that will be suspect, and diagnosis should begin there.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 4: The exhaust system has very low back pressure under normal conditions. If the exhaust system is restricted, a significant increase in the exhaust pressure is noticed on the J 35314-A . See «Special Tools»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system__special-tools) . Removing the HO2S sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
2. 5: This step will isolate the catalytic converter from the remainder of the exhaust system.
3. 8: Confirming that the condition has been fixed is essential. If the symptom still exists and the vehicle has a dual exhaust system, proceed to Step 2 and repeat diagnostic procedure on the opposite exhaust pipe.

Restricted Exhaust

Exhaust Leakage

Exhaust Leakage

Exhaust Noise

Exhaust Noise

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/xlr/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Exhaust Vibration/Noise - Exhaust Flow Control System Malfunction

Exhaust tail pipe flow valve control module receives throttle position sensor and RPM information via serial data from powertrain control module (PCM). The exhaust tail pipe flow valve control module uses this information to determine if to command exhaust tail pipe flow control valve solenoid ON or OFF. When commanded OFF the exhaust tail pipe flow control valve solenoid allows vacuum to flow to close exhaust valve.

Schematic Reference

Exhaust System Schematics

Connector End View Reference

Exhaust System Connector End Views

Electrical Information Reference

1. «Circuit Testing»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Scan Tool Reference

Scan Tool Data List for exhaust tail pipe flow valve control module

1. Ignition OFF, disconnect the exhaust tail pipe flow control valve solenoid connector.
2. Ignition ON, use scan tool to command exhaust flow control relay ON, measure for 10 volts or above between the exhaust tail pipe flow control valve solenoid supply voltage circuit and ground. If under 10 volts, test for open/high resistance in exhaust tail pipe flow control valve solenoid supply voltage circuit. If circuit test normal replace the exhaust tail pipe flow valve control module.
3. Connect a test lamp between the exhaust tail pipe flow control valve solenoid supply voltage circuit and ground circuit. Verify that the test lamp illuminates. If the test lamp does not illuminate, test the ground circuit for open or high resistance.
4. If all circuits test normal replace the exhaust tail pipe flow control valve solenoid.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Exhaust Tail Pipe Flow Control Valve Solenoid Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system)
2. «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for exhaust tail pipe flow valve control module replacement, setup, and programming

Removal Procedure

1. Remove the powertrain. Refer to «Powertrain Removal and Installation»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-46l-lh2-2-of-5) .
2. Remove the exhaust manifold and catalytic converter assembly bolt (1) securing the pipe to the bell housing.
3. Remove the oxygen sensors. Refer to «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) and «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
4. Remove the left exhaust manifold heat shield bolts (2).
5. Remove the left exhaust manifold heat shield (1).
6. Remove the exhaust manifold bolts and nuts.
7. Remove the exhaust manifold.
8. Remove the left exhaust manifold gasket.
9. Discard the gasket.

Installation Procedure

1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953489), or equivalent to the threads of the exhaust manifold bolts and studs.
2. Position the exhaust manifold and a NEW gasket into place.
3. Install the exhaust manifold bolts and nuts. Tighten: Tighten the exhaust manifold bolts and nuts to 25 N.m (18 lb ft). Tighten the exhaust manifold bolts and nuts beginning with the center two nuts. Alternate from side-to-side, working toward the outside bolts and nuts.
4. Install the exhaust manifold catalytic converter hanger bolt (1) to the bell housing. Tighten: Tighten the exhaust hanger bolt to 50 N.m (37 lb ft).
5. Install the left exhaust manifold heat shield (1) and bolts (2). Tighten: Tighten the exhaust manifold heat shield bolts to 10 N.m (89 lb in).
6. Install the oxygen sensors. Refer to «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) and «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
7. Install the powertrain. Refer to «Powertrain Removal and Installation»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-46l-lh2-2-of-5) .

1. Remove the powertrain. Refer to «Powertrain Removal and Installation»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-46l-lh2-2-of-5) .
2. Remove the bolt (1) securing the catalytic converter pipe to the bell housing.
3. Remove the oxygen sensors. Refer to «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) and «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
4. Remove the right exhaust manifold heat shield bolts (2).
5. Remove the right exhaust manifold heat shield (1).
6. Remove the exhaust manifold bolts and nuts (2).
7. Remove the exhaust manifold, and old gasket. Discard the gasket.

1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts and studs.
2. Position the exhaust manifold and a NEW gasket into place.
3. Install the exhaust manifold bolts and nuts. Tighten: Tighten the exhaust manifold bolts and nuts to 25 N.m (18 lb ft). Tighten the exhaust manifold bolts and nuts beginning with the center two nuts. Alternate from side-to-side, working toward the outside bolts and nuts.
4. Install the exhaust manifold and catalytic converter bolt (1) securing the pipe to the bell housing. Tighten: Tighten the exhaust hanger bolt to 50 N.m (37 lb ft).
5. Install the oxygen sensors. Refer to «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) and «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
6. Install the right exhaust manifold heat shield and bolts. Tighten: Tighten the exhaust manifold heat shield bolts to 10 N.m (89 lb in).
7. Install the powertrain. Refer to «Powertrain Removal and Installation»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-46l-lh2-2-of-5) .

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Remove the intermediate exhaust pipe hanger lower bolts (3).
3. Remove the left and right exhaust manifold nuts (2).
4. Lower the front of the intermediate exhaust pipe (1).
5. Remove the exhaust seal (3).

1. Install a NEW exhaust seal (3).
2. Raise the front of the intermediate exhaust pipe (1).
3. Install the left and right exhaust manifold nuts (2). Tighten: Tighten the exhaust manifold nuts to 20 N.m (15 lb ft).
4. Install the exhaust pipe hanger lower bolts (3). Tighten: Tighten the exhaust pipe hanger bolts to 50 N.m (37 lb ft).
5. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Install adjustable jack stands under the front and rear of the intermediate pipe.
3. Loosen the exhaust muffler band clamps (2, 5).
4. Separate the left and right tailpipe/muffler assemblies from the intermediate pipe.
5. Remove the exhaust pipe hanger lower bolts (3).
6. Remove the exhaust manifold nuts (2).
7. Lower the jack stands.
8. Remove the intermediate pipe from the jack stands.

Note. Refer to Exhaust System Inspection Notice .

1. Install the intermediate pipe to the jack stands.
2. Raise the jack stands in order to position the intermediate pipe.
3. Install ALL exhaust clamps and bolts until snug to ensure correct alignment of the intermediate pipe.
4. Remove the adjustable jack stands.
5. Tighten the exhaust muffler clamps (2, 5). Tighten: Tighten the exhaust clamps bolts to 44 N.m (32 lb ft).
6. Tighten the exhaust manifold nuts (2). Tighten: Tighten the exhaust manifold nuts to 20 N.m (15 lb ft).
7. Tighten the exhaust pipe hanger lower bolts (3). Tighten: Tighten the exhaust pipe hanger bolts to 50 N.m (37 lb ft).
8. Lower the vehicle.

1. Remove the intermediate exhaust pipe. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
2. Remove the upper exhaust pipe hanger bolts (1).
3. Remove the exhaust pipe hanger.

1. Install the exhaust pipe hanger.
2. Install the upper exhaust pipe hanger bolts (1). Tighten: Tighten the exhaust pipe hanger bolts to 50 N.m (37 lb ft).
3. Install the intermediate exhaust pipe. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Loosen the left exhaust muffler clamp (5).
3. Slide the muffler out from the hanger (1).
4. Remove the left muffler.

Note. Refer to Exhaust System Inspection Notice .

1. Mark the position of the muffler band clamp (5) on the intermediate exhaust pipe.
2. Remove the muffler band clamp from the intermediate exhaust pipe by grinding the weld.
3. Install a new muffler band clamp on the intermediate exhaust pipe.
4. Install the left muffler.
5. Slide the muffler into the hanger (1).
6. Position the new muffler band clamp (5) on the intermediate exhaust pipe using the alignment mark created previously. The muffler band clamp bolt must not be positioned below the exhaust pipe.
7. Tighten the right side exhaust muffler clamp. Tighten: Tighten the exhaust muffler clamp to 44 N.m (32 lb ft).
8. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Loosen the right side exhaust muffler clamp (2).
3. Slide the muffler out from the hanger (1).
4. Remove the right muffler.

Note. Refer to Exhaust System Inspection Notice .

1. Mark the position of the muffler band clamp (2) on the intermediate exhaust pipe.
2. Remove the muffler band clamp from the intermediate exhaust pipe by grinding the weld.
3. Install a new muffler band clamp on the intermediate exhaust pipe.
4. Install the right muffler.
5. Slide the muffler into the hanger.
6. Position the new muffler band clamp (2) on the intermediate exhaust pipe using the alignment mark created previously. The muffler band clamp bolt must not be positioned below the exhaust pipe.
7. Tighten the right side exhaust muffler clamp. Tighten: Tighten the exhaust muffler clamp to 44 N.m (32 lb ft).
8. Lower the vehicle.

1. Disconnect the quick connect fitting (2) at the front of dash. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
2. Disconnect the vacuum line fitting (1) from the rear of the supercharger.
3. Remove the vacuum line from the retainer (3).
4. Remove the exhaust flow control vacuum check valve and engine compartment vacuum line from the vehicle.

1. Install the exhaust flow control vacuum check valve and engine compartment vacuum line to the vehicle.
2. Install the vacuum line to the retainer (3).
3. connect the vacuum line fitting (1) to the rear of the supercharger.
4. Connect the quick connect fitting (2) at the front of dash. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Disconnect the vacuum line (1) from the vacuum tank located behind the right rear quarter panel.
3. Remove the right rear tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/xlr/i-2003-2009/remont/wheel-tire-system/#tires-and-wheels) .
4. Remove the right rear wheel house liner. Refer to «Rear Wheelhouse Liner Panel Replacement»(/cadillac/xlr/i-2003-2009/remont/exterior-body-panels/#body-rear-end) .
5. If the vacuum tank is not damaged, grasp the vacuum tank and break it free from the rear compartment panel. If the vacuum tank is broken, use suitable tools for removal.
6. Remove the vacuum tank from the rear compartment panel.

1. Clean the area of the rear compartment panel where the vacuum tank mounts (4). Use an abrasive wheel if necessary.
2. Clean the rear compartment panel and the vacuum tank mounting surface with an alcohol based cleaner.
3. Apply two part epoxy GM P/N 89020330 (Canadian P/N 89020332) or equivalent to the mounting surface of the vacuum tank.
4. Install the vacuum tank to the vehicle in the location shown (4). Ensure that the vacuum line will reach the vacuum tank.
5. Hold the tank in position with masking tape while the epoxy dries.
6. Allow the epoxy to dry for thirty minutes before removing the masking tape.
7. Connect the vacuum line (1) to the vacuum tank.
8. Install the wheel house liner. Refer to «Rear Wheelhouse Liner Panel Replacement»(/cadillac/xlr/i-2003-2009/remont/exterior-body-panels/#body-rear-end) .
9. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/xlr/i-2003-2009/remont/wheel-tire-system/#tires-and-wheels) .
10. Lower the vehicle.

1. Remove the engine sight shield. Refer to «Intake Manifold Sight Shield Replacement»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-1-of-5) .
2. Disconnect the quick connect fitting (4) at the front of dash. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
3. Disconnect the chassis fuel bundle retainer (1) from the upper front of dash mounting stud.
4. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
5. Remove the exhaust intermediate pipe. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
6. Remove the driveline closeout panel. Refer to «Driveline Tunnel Closeout Panel Replacement»(/cadillac/xlr/i-2003-2009/remont/driveshaft-universal-joints/#propeller-shaft) .
7. Disconnect the front chassis vacuum line from the underbody retainers (3,5,6 and 7).
8. Disconnect the front chassis vacuum line quick connect fitting (2) located on the left side of the vehicle, forward of the rear drive module. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
9. Remove the front chassis vacuum line from the vehicle.

1. Install the front chassis vacuum line to the vehicle.
2. Connect the front chassis vacuum line quick connect fitting (2). Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
3. Install the front chassis vacuum line to the underbody retainers (3,5,6 and 7).
4. Install the driveline closeout panel. Refer to «Driveline Tunnel Closeout Panel Replacement»(/cadillac/xlr/i-2003-2009/remont/driveshaft-universal-joints/#propeller-shaft) .
5. Install the exhaust intermediate pipe. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
6. Lower the vehicle.
7. Connect the chassis fuel bundle retainer (1) to the upper front of dash mounting stud.
8. Connect the quick connect fitting (4) at the front of dash. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
9. Install the engine sight shield. Refer to «Intake Manifold Sight Shield Replacement»(/cadillac/xlr/i-2003-2009/remont/mechanical/#engine-mechanical-44l-1-of-5) .

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Remove the right side muffler assembly. Refer to «Exhaust Muffler Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
3. Remove the intermediate exhaust pipe assembly. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
4. Disconnect the vacuum line quick connect fitting (2) located on the left side of the vehicle forward of the rear drive module. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
5. Remove the bolts from the retainer straps (1, 3) along the length of the rear chassis vacuum line.
6. Disconnect the rear chassis vacuum line quick connect fitting (4). Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
7. Remove the rear chassis vacuum line (2) from the vehicle.

1. Install the vacuum line (2) to the vehicle.
2. Connect the rear chassis vacuum line quick connect fitting (4). Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
3. Install the bolts to the retainer straps (1,3) along the length of the rear chassis vacuum line. Tighten: Tighten the vacuum line strap bolts to 10 N.m (89 lb in).
4. Connect the vacuum line quick connect fitting (2) located on the left side of the vehicle forward of the rear drive module. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
5. Install the intermediate exhaust pipe assembly. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
6. Install the right side muffler assembly. Refer to «Exhaust Muffler Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
7. Lower the vehicle.

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Disconnect the vacuum line fitting (1) from the flow control valve vacuum tank.
3. Disconnect the vacuum line fitting (1) from the flow control valve solenoid.
4. Disconnect the vacuum line fitting (1) from the rear chassis vacuum line. Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
5. Remove the vacuum line from the vehicle.

1. Install the vacuum line to the vehicle.
2. Connect the vacuum line quick connect fitting (1). Refer to «Plastic Collar Quick Connect Fitting Service»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-44l-introduction-2-of-2) .
3. Connect the vacuum line fitting (1) to the flow control valve solenoid.
4. Connect the vacuum line fitting (1) to the flow control valve vacuum tank.
5. Lower the vehicle.

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Disconnect the vacuum line fitting (4) from the flow control valve solenoid. The graphic shows the rear fascia removed for clarity.
3. Disconnect the vacuum line fittings (1 and 3) from the flow control valves.
4. Disengage the retainer clips along the length of the vacuum line (2).
5. Remove the vacuum line from the vehicle.

1. Install the vacuum line to the vehicle.
2. Install the retainer clips along the length of the vacuum line (2).
3. Connect the vacuum line fittings (1 and 3) to the flow control valves.
4. Connect the vacuum line fitting (4) to the flow control valve solenoid.
5. Lower the vehicle.

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/xlr/i-2003-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) .
2. Disconnect the solenoid electrical connector (3).
3. Disconnect the vacuum line fittings (1 and 5) from the solenoid.
4. Remove the solenoid (2) from the solenoid bracket.

1. Install the solenoid (2) to the solenoid bracket.
2. Connect the vacuum line fittings (1 and 5) to the solenoid.
3. Connect the solenoid electrical connector (3).
4. Lower the vehicle.

1. Remove the battery.
2. Disconnect both electrical connectors.
3. Detach the exhaust tail pipe flow valve control module by pulling off two-sided tape.
4. Remove the exhaust tail pipe flow valve control module.

1. Install the exhaust tail pipe flow valve control module.
2. Attach the exhaust tail pipe flow valve control module using a new piece of two-sided tape.
3. Connect both electrical connectors.
4. Install the battery.
5. Refer to «Control Module References»(/cadillac/xlr/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for programming and setup information.

1. Remove the muffler. Refer to «Exhaust Muffler Replacement - Left Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) or «Exhaust Muffler Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
2. Remove the muffler hanger bolt (1) and hanger.
3. Remove the hanger (2).

1. Install the hanger (2).
2. Install the muffler hanger and bolt (1). Tighten: Tighten the muffler hanger nuts to 16 N.m (12 lb ft).
3. Install the muffler. Refer to «Exhaust Muffler Replacement - Left Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) or «Exhaust Muffler Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .

1. Remove the intermediate pipe. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
2. Drill out the exhaust heat shield rivets.
3. Remove the exhaust heat shield.

1. Install the exhaust heat shield.
2. Install new exhaust heat shield rivets.
3. Install the intermediate pipe. Refer to «Intermediate Pipe Replacement»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .

1. Remove the left and right muffler. Refer to «Exhaust Muffler Replacement - Left Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) and «Exhaust Muffler Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .
2. Drill out the muffler heat shield rivets.
3. Remove the heat shield washers and shield.

1. Install the heat shield and washers.
2. Install new heat shield rivets.
3. Install the left and right muffler. Refer to «Exhaust Muffler Replacement - Left Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) and «Exhaust Muffler Replacement - Right Side»(/cadillac/xlr/i-2003-2009/remont/exhaust/#engine-exhaust-system) .

Exhaust System Description

The exhaust system carries exhaust gases, treated by the catalytic converter, through a resonator, if applicable and into the exhaust muffler where exhaust noise is less.

In order to secure the exhaust pipe to the exhaust manifold, a flange and seal-joint coupling is utilized. The exhaust system may utilize a slip-joint coupling design with a clamp and a U-bolt or a flange connection with a gasket.

Exhaust hangers and rubber insulators help to support the weight of the exhaust pipe along with insulating any exhaust system vibration, rattle, or noise.

Exhaust hangers also space the exhaust system away from the underbody of the vehicle and allows the exhaust system to expand as the exhaust system warms up.

Exhaust heat shields are used to protect the body and other components from damage due to the heat from the exhaust system.

The exhaust system may be comprised of the following components

1. Exhaust manifold
2. Exhaust pipes
3. Catalytic converters
4. Exhaust muffler
5. Exhaust resonator, if equipped
6. Exhaust tail pipe, if equipped
7. Exhaust hangers
8. Exhaust heat shields

Resonator

Some exhaust systems are equipped with a resonator. The resonator, located either before or after the muffler, allows the use of mufflers with less back pressure. Resonators are used when vehicle characteristics require specific exhaust tuning.

Catalytic Converter

The catalytic converter is an emission control device added to the engine exhaust system in order to reduce hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) pollutants from the exhaust gas.

The catalytic converter is comprised of a ceramic monolith substrate, supported in insulation and housed within a sheet metal shell. The substrate may be washcoated with 3 noble metals

1. Platinum (Pt)
2. Palladium (Pd)
3. Rhodium (Rh)

The catalyst in the converter is not serviceable.

Muffler

The exhaust muffler reduces the noise levels of the engine exhaust by the use of tuning tubes. The tuning tubes create channels inside the exhaust muffler that lower the sound levels created by the combustion of the engine.

Exhaust Tail Pipe Flow Control System Description and Operation

The Exhaust Flow Control (EFC) System enhances engine performance. The system has 2 modes of operation

1. Normal
2. Competition

Normal Mode

When the vehicle is stationary with the engine running the exhaust flow control module (EFCM) commands the vacuum solenoid On, which supplies engine vacuum to both exhaust flow control valves. This causes the valves to close, diverting exhaust flow through a baffled path inside the mufflers. As vehicle speed increases, throttle position reaches 25 percent or greater and engine speed reaches 3500 RPM, the EFCM commands the vacuum solenoid off. This causes the valves to open, diverting exhaust flow through an un-baffled path inside the mufflers, thus enhancing engine performance.

Competition Mode

When traction control is driver disabled, vehicle speed increases, throttle position reaches 25 percent or greater and engine speed reaches 3000 RPM, the EFCM commands the vacuum solenoid off. This causes the valves to open; diverting exhaust flow through an un-baffled path inside the mufflers more frequently and at lower engine speeds.

The system also delays exhaust valve activity during wide-open throttle acceleration to inhibit exhaust valve actuation when the accelerator pedal is released and reapplied while shifting gears.

The EFCM has the ability to detect electrical malfunctions within the system. Any electrical malfunction detected will cause the system to be disabled and increased exhaust audibility.

The system uses the engine control module (ECM), body control module (BCM), electronic brake control module (EBCM), EFCM, exhaust flow control valve vacuum solenoid, vacuum reservoir, vacuum lines, 2 exhaust flow control valves and the serial data circuit to perform the system functions.

Special Tools

Special Tools Illustration Tool Number/ Description J 35314-A Exhaust Back Pressure Gage J 35555 Metal Mityvac

Scheme 7

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Scan Tool Data List
• Diagnostic Repair Verification
• Control Module References
• Exhaust Service Caution
• Diagnostic Starting Point - Engine Mechanical
• Diagnostic Starting Point - Engine Mechanical
• Hot Exhaust System Caution
• Heated Oxygen Sensor Replacement - Bank 1 Sensor 1
• Powertrain Removal and Installation
• Heated Oxygen Sensor Replacement - Bank 2 Sensor 1
• Fastener Notice
• Lifting and Jacking the Vehicle
• Protective Goggles and Glove Caution
• Exhaust System Inspection Notice
• Tire and Wheel Removal and Installation
• Rear Wheelhouse Liner Panel Replacement
• Intake Manifold Sight Shield Replacement
• Driveline Tunnel Closeout Panel Replacement
• Symptoms - Engine Exhaust
• Exhaust System Schematics
• Exhaust System Description
• Exhaust Leakage
• Exhaust Noise
• Exhaust Tail Pipe Flow Control System Description and Operation
• Diagnostic Starting Point - Engine Exhaust
• Special Tools
• Fastener Tightening Specifications