System Check - Restricted Exhaust

Diagnostic Chart:

Diagram:

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 Front Oxygen Sensor (O2S 1) location. Once the test is completed, coat threads with anti-seize compound P/N 5613695 or equivalent prior to O2S re-installation.


TEST DESCRIPTION

The number(s) below refer(s) to the step number(s) on the Diagnostic Table.

1. The OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when the malfunction occurred. The scan tool stores this data 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.