Section 12.8
Faulty Exhaust System

To determine if a faulty exhaust system is causing lack of power, perform the following steps:‪

1. Monitor the exhaust pressure using DDDL 7.0. Connect the scan tool and check the pressure on the DPF sensor.

   To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

   ENGINE EXHAUST ‪
   To avoid injury from inhaling engine exhaust, always operate the engine in a well-ventilated area. Engine exhaust is toxic.‪

2. Start and run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
3. Install the vehicle on a chassis dynamometer and run the engine speed to full load.
   1. If the exhaust back pressure at full load is less than 10.1 kPa (3.0 in.Hg), check for high inlet air temperature; refer to "12.9 High Inlet Air Temperature" .
   2. If the exhaust back pressure at full load is 10.1 kPa (3.0 in.Hg) or greater, refer to "12.8.1 Engine Exhaust System Resolution" .

Section 12.8.1
Engine Exhaust System Resolution

Perform the following steps to resolve the engine exhaust system:‪

1. Visually inspect the engine exhaust system; refer to OEM guidelines.
2. Remove the Aftertreatment Device (ATD), refer to the Aftertreatment System Technician's Guide (7SE63).
3. Install the aftertreatment test pipes (J-48388-1) for 5 inch exhaust, or aftertreatment test pipes (J-48388-2) for 4 inch exhaust. Deactivate the pressure and temperature sensors using DDDL 7.0.
4. Verify exhaust system resolution; refer to "12.8.1.1 Test the Engine with Replaced Exhaust System" .

Section 12.8.1.1
Test the Engine with Replaced Exhaust System

Perform the following steps to determine if replaced engine exhaust system components resolved lack of power condition:‪

1. Start and run the engine.
2. Test drive the vehicle to ensure lack of power has been resolved.
   1. If the lack of power has been resolved refer Aftertreatment System Technician's Guide (7SE63) for aftertreatment diagnostics.
   2. If lack of power occurred during the test drive, shut down the engine. Reinstall the aftertreatmnet. Check for high inlet air temperature; refer to "12.9 High Inlet Air Temperature" .