Pinpoint Test A: Restricted Exhaust System Test
- A1 EXHAUST SYSTEM INSPECTION
- With the vehicle in NEUTRAL, position it on a hoist. For additional information, refer to JACKING & LIFTING .
- Inspect the exhaust system for damage or deterioration. Look for cracks, punctures, leaks, loose connections, dents or unusual bending.
- Is the exhaust system OK?
WARNING: If equipped with fire suppression system, depower the system. For important safety warnings and procedures, refer to FIRE SUPPRESSION SYSTEM .Yes : GO to A2.
No : REPAIR or INSTALL any damaged or deteriorated exhaust components. Test the system for normal operation. If equipped with fire suppression system, GO to A4.
- A2 BACK PRESSURE TEST
- Connect a tachometer.
- Using the special tool, remove the upstream heated oxygen sensor (HO2S).
- Install the back pressure gauge.
- Start the engine and gradually increase the engine speed to 2,000 rpm with the transmission in NEUTRAL.
- Is the back pressure greater than 27.6 kPa (4 psi)?
Yes : GO to A3.
No : No indications of a restriction have been detected. CONDUCT a diagnosis on other suspect systems. CLEAR the DTCs. If equipped with fire suppression system, GO to A4.
- A3 BACK PRESSURE TEST - CATALYTIC CONVERTER(S) ON, MUFFLER(S) OFF
- Turn the engine OFF.
- Disconnect the muffler assembly from the catalytic converter.
- Repeat the back pressure test.
- Is the back pressure greater than 27 kPa (4 psi)?
Yes : The restriction is in the catalytic converter. INSTALL a new catalytic converter. INSPECT the muffler to be sure the catalytic converter foreign material has not entered the muffler. CLEAR the DTCs. TEST the system for normal operation. If equipped with fire suppression system, GO to A4.
No : The restriction is in the muffler assembly. INSTALL a new muffler. CLEAR the DTCs. TEST the system for normal operation. If equipped with fire suppression system, GO to A4.
- A4 REPOWER THE FIRE SUPPRESSION SYSTEM
- Verify that the fire suppression system is repowered. For additional information, refer to FIRE SUPPRESSION SYSTEM .
- Is the fire suppression system repowered?
WARNING: If equipped with fire suppression system, depower the system. For important safety warnings and procedures, refer to FIRE SUPPRESSION SYSTEM .Yes : Fire suppression system repowering is complete.
No : Refer to FIRE SUPPRESSION SYSTEM for fire suppression system depowering and repowering procedure.