verter, muffler, and a resonator with connecting pipes
in-between (Fig. 1). The system is serviced in two
sections; the catalytic converter and pipe, and the
muffler and resonator with connecting pipe. A band
clamp is used to connect the joint between the two

components. Three support hanger rods with rubber
isolators are used to support and isolate the exhaust
system. A flexible joint, integral to the catalytic con-
verter, allows for engine movement. On vehicles
equipped with AWD, an additional heat shield is
mounted to the catalytic converter. The exhaust sys-
tem is tuned for each vehicle/powertrain combination.

Fig. 1 Exhaust System - Typical (All Vehicles)

1 - CATALYTIC CONVERTER

4 - SUPPORT - RESONATOR

2 - BAND CLAMP

5 - RESONATOR

3 - SUPPORTS - MUFFLER

6 - MUFFLER

EXHAUST SYSTEM

11 - 1

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - EXCESSIVE
EXHAUST SYSTEM NOISE

CONDITION

POSSIBLE CAUSES

CORRECTION

EXCESSIVE EXHAUST NOISE

(UNDER HOOD)

1. Exhaust manifold cracked or
broken.

1. Replace manifold.

2. Manifold to cylinder head leak.

2. Tighten manifold and/or replace
gasket.

3. EGR Valve to manifold gasket
leakage.

3. Tighten fasteners or replace
gasket.

4. EGR Valve to EGR tube gasket
leakage.

4. Tighten fasteners or replace
gasket.

5. EGR tube to manifold tube
leakage.

5. Tighten tube nut.

6. Exhaust flex-joint to manifold
leak.

6. Tighten joint fasteners and/or
replace gasket.

7. Exhaust flex-joint.

7. Replace catalytic converter
assembly.

8. Pipe and shell noise from front
exhaust pipe.

8. Characteristic of single wall pipe.

EXCESSIVE EXHAUST NOISE

1. Leak at exhaust pipe joints.

1. Tighten clamps at leaking joints.

2. Burned or rusted out muffler
assembly or exhaust pipe.

2. Replace muffler resonator tailpipe
assembly or exhaust pipe with
catalytic converter assembly.

3. Burned or rusted out resonator.

3. Replace muffler resonator tailpipe
assembly.

4. Restriction in exhaust system.

4. Perform Exhaust System
Restriction Check. Replace
component as necessary.

5. Converter material in muffler.

5. Replace muffler and converter
assemblies. Check fuel injection and
ignition systems for proper
operation.

DIAGNOSIS AND TESTING - EXHAUST SYSTEM
RESTRICTION CHECK

Exhaust system restriction can be checked by mea-

suring back pressure using the DRB III

t and PEP

module pressure tester.

WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-

VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.

NOTE: For Special Tool identification, (Refer to 11 -
EXHAUST SYSTEM - SPECIAL TOOLS).

(1) Disconnect and remove the upstream (before

catalytic converter) oxygen sensor. (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/O2 SENSOR -
REMOVAL)

(2) Install the Exhaust Back Pressure Fitting

Adaptor CH8519.

(3) Connect the Low Pressure Sensor (15 psi)

CH7063 to the back pressure fitting.

11 - 2

EXHAUST SYSTEM

EXHAUST SYSTEM (Continued)

(4) Following the PEP module instruction manual,

connect all required cables to the DRB III

t and PEP

module. Select the available menu options on the
DRBIII

t display screen for using the digital pressure

gauge function.

(5) Apply the park brake and start the engine.
(6) With transmission in Park or Neutral, raise

engine speed to 2000 RPM. Monitor the pressure
readings on the DRBIII

t. Back pressure should not

exceed specified limit. Refer to specification in table
below EXHAUST BACK PRESSURE LIMITS .

(7) If pressure exceeds maximum limits, inspect

exhaust system for restricted component. For further
catalytic converter inspection procedures, (Refer to 11
- EXHAUST SYSTEM/CATALYTIC CONVERTER -
INSPECTION). Replace component(s) as necessary.

EXHAUST BACK PRESSURE LIMITS

Exhaust Back Pressure Limit (Max)

Vehicle in Park/Neutral

(no load) @2000 RPM

3.45 Kpa (0.5 psi)

INSPECTION

Inspect the exhaust pipes, catalytic converters,

muffler, and resonators for cracked joints, broken
welds and corrosion damage that would result in a
leaking exhaust system. Inspect the clamps, support
brackets, and insulators for cracks and corrosion
damage.

NOTE: Slip joint band clamps are spot welded to
exhaust system. If a band clamp must be replaced,
the spot weld must be ground off.

ADJUSTMENTS

A misaligned exhaust system is usually indicated

by a vibration, rattling noise, or binding of exhaust
system components. These noises are sometimes hard
to distinguish from other chassis noises. Inspect
exhaust system for broken, damaged or loose compo-
nents such as; clamps, heat shields, isolators, and
hanger brackets. Replace or tighten as necessary. It
is important that exhaust system clearances and
alignment be maintained.

Perform the following procedures to align the

exhaust system:

(1) Loosen band clamp at catalytic converter pipe

to muffler/resonator assembly.

(2) Align the exhaust system by inserting pipe

inward or outward until specification is achieved as
shown in (Fig. 2).

(3) Tighten band clamp to 54 N·m (40 ft. lbs.).

SPECIFICATIONS

TORQUE

DESCRIPTION

N·m

Ft.

Lbs.

In.

Lbs.

Band Clamp

—

Cross-over Pipe—Fastener

—

Exhaust Manifold Flange—Fastener

—

325

Heat Shield (Muffler)—Fastener

2.6

—

Heat Shield (Toe Board)—Fastener

2.6

—

Heat Shield (Resonator Pipe)—
Fastener

2.6

—

Insulator Mounting Bracket—Bolts

—

250

Fig. 2 Exhaust System Alignment

1 - HANGER BRACKET TO BODY
2 - ISOLATOR
3 - HANGER - MUFFLER/RESONATOR SUPPORT
4 - 6 mm (0.25 in.)

EXHAUST SYSTEM

11 - 3

EXHAUST SYSTEM (Continued)

Content .. 333 334 335 336 ..