Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
EGR Monitor and Readiness Code: Procedure
2008 Honda Civic Si, 4D SedanSECTION Procedure
WARNING: This page is about a different variant/trim than selected.
- Connect the HDS to the DLC.
- Start the engine.
- Drive at a steady speed with the A/T in D or M/T in 4th, at 50-62 mph (80-100 km/h) or above for more than 10 seconds.
- With the A/T in D or M/T in 4th, decelerate from 62 mph (100 km/h) or above by completely releasing the throttle for at least 5 seconds. If the engine is stopped during this procedure, go to step 3 and do the procedure again.
- Check the OBD status screen for DTC P0401 in the DTCs MENU with the HDS.
- If it is PASSED, readiness is complete.
- If it is not PASSED, go to step 3 and retest.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.