Hard reboot for ECU needed possibly?

Tiny
JESSS
  • MEMBER
  • 1998 NISSAN ALTIMA
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 120,000 MILES
Installed used engine, changed spark plugs, wires, dist cap, rotor, air filter, fuel filter, Mass Airflow Sensor, EGR, O2 Sensor

No vacuum leaks.

Check engine light still comes on intermittently reading lean bank one.

Is there a hard reset for the ECU I should perform specific to my car to stop this so I can pass smog?
Monday, January 19th, 2026 AT 4:52 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,601 POSTS
Yep, you can try a hard reboot, here is a video to show you how.

https://www.youtube.com/watch?v=INiDRO5A5MY

Is there any intake or exhaust leaks, these both can cause a lean mixture, here is a guide to help.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

This video will show you how to check for vacuum leaks.

https://www.youtube.com/watch?v=LRKWV4Are5c&pp=0gcJCYcKAYcqIYzv

Please upload a short video with the engine running in your response, so I can see what's going on. Please go over these guides and get back to us.

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Tuesday, January 20th, 2026 AT 9:44 AM

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