*Important Note-Before starting the diagnosis process, verify that the ECM calibration is up to date. An outdated ECM calibration can lead to issues with sensors and modules.
- If both 1922 and 1921 are active at the same time, troubleshoot 1922 first.
- Repair any codes from the following list before 1922: Aftertreatment regeneration
- Aftertreatment differential pressure, Aftertreatment DPF, Aftertreatment DOC, Fuel, Engine misfire, EGR, Turbocharger, Intake manifold, Intake throttle, EGR differential pressure.
- Check air filter. If plugged replace.
- Inspect EGR pressure sensor ports for build-up. If plugged, clean ports.
- Inspect DPF pressure sensor and tubes. Verify tubes are not plugged. Verify that sensor is functioning correctly by verifying the signal volage with a scanner. If it doesn’t read 0.5 volts, or a bit higher, then sensor is at fault.
- Damaged DPF is suspected if all previous steps were completed, and no issues were found.
TROUBLESHOOTING SHACK 