Non-Trouble Code Procedures

DIAGNOSIS AND TESTING - EXHAUST SYSTEM RESTRICTION
Exhaust system restriction can be checked by measuring back pressure using the DRB III and PEP module pressure tester.

WARNING: THE NORMAL OPERATING TEMPERATURE 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 CONVERTER RISES TO A HIGH LEVEL AFTER A SHORT PERIOD OF ENGINE OPERATION TIME.

1. Disconnect and remove the upstream (before catalytic converter) oxygen sensor.
2. Install the Exhaust Back Pressure Fitting Adapter CH8519.
3. Connect the Low Pressure Sensor (15 psi) CH7063 to the back pressure fitting.
4. Following the PEP module instruction manual, connect all required cables to the DRB III and PEP module. Select the available menu options on the DRB III display screen for using the digital pressure gauge function.
5. Start engine and monitor pressure readings.
6. Raise engine speed to 2000 RPM. Back pressure should not exceed specified limit. Refer to specification.

NOTE: For applications with dual catalytic converters, repeat test on opposite converter using the previous steps.





7. If pressure exceeds maximum limits, inspect exhaust system for restricted component. Replace component(s) as necessary.