SPN 411/FMI 0
This diagnosis is typically EGR differential pressure failed high (Low Box).
Check as follows:
- Disconnect the EGR Delta P Sensor.
- Inspect the EGR Delta P Sensor harness connector for bent, spread or corroded pins.
- If connector damage is found, repair as necessary. Refer to “39.1.1 Verify Repairs” .
- If no damage is found, go to the next step.
- Check EGR function to ensure it closes (key OFF).
- Remove the EGR Delta P Sensor.
- Inspect the sensor tubes for plugging.
- If no EGR tube obstructions are found, replace the EGR Delta P Sensor. Refer to “39.1.1 Verify Repairs” .
- If EGR tube obstructions are found clean or replace tubes as necessary. Refer to “39.1.1 Verify Repairs” .
Verify repairs as follows:
- Turn ignition OFF.
- Reconnect any electrical connections that were disconnected to perform the diagnosis.
- Clear codes with DDDL 7.0 or latest version.
ENGINE EXHAUST To avoid injury from inhaling engine exhaust, always operate the engine in a well-ventilated area. Engine exhaust is toxic.
- Start and bring engine up to operating temperature (over 140°F/60°C).
- Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes.