Restricted Exhaust System Check

Restricted Exhaust System Check




System Description
Proper diagnosis for a restricted exhaust system is essential before any components are replaced. Using the Restricted Exhaust System Check table should determine if the exhaust system is restricted. The best place for checking the exhaust system is at the O2S 1 location. Once the test is completed, coat threads with anti-seize compound prior to O2S re-installation.

Step 1:

Steps 2 - 5:

Steps 6 - 7:

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored on the scan tool for later reference.
3. The exhaust system under normal conditions has very low back pressure. If the exhaust system is restricted, a noticeable increase in exhaust pressure is noticed on the gauge.
4. If no high back pressure is found at idle, increasing the engine speed to 3000 RPM may find a slight restriction. The added engine speed increases the exhaust flow which will help determine if there is a slight restriction.