# Service Engine Light **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [October 9, 2007, 12:42am UTC](https://community.cartalk.com/t/service-engine-light/5686 "2007-10-09T00:42:07Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![dmoore](https://avatars.discourse-cdn.com/v4/letter/d/35a633/32.png) [@dmoore](https://community.cartalk.com/u/dmoore)\ **Post date:** [October 9, 2007, 12:42am UTC](https://community.cartalk.com/t/service-engine-light/5686/1 "2007-10-09T00:42:07Z")
I just purchased a 96 Nissan Sentra GXE from a private seller. Took it to get safety and emission test and it failed. The service engine light had been pulled and the car registered the P0400 EGR Flow malfunction. After talking to the dealership, they said it was common that a vacuum tube is broken or plugged. I checked all tubes and one tube that is about 4inches long with a 90 degree bend was crumbling. The guy at the dealership suspected that that is most likely the problem. He also said that the service engine light will go off after a few days of sitting. I let the car sit, and the light still comes on. Is there a way to reset the light to see if it comes back on? It should if another problem exists. I would like to try and save money from getting it reset at the dealership and Autozone will not reset it. Someone Help Please!! ---
**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\ **Post date:** [October 9, 2007, 1:04am UTC](https://community.cartalk.com/t/service-engine-light/5686/2 "2007-10-09T01:04:18Z")
Did the person at Auto Zone say why they would’t erase the code? With the scan tool connected, it’s just a press of the ERASE button. This is not too difficult. ---
**Author:** ![taoyuanming](https://avatars.discourse-cdn.com/v4/letter/t/2acd7d/32.png) [@taoyuanming](https://community.cartalk.com/u/taoyuanming)\ **Post date:** [October 9, 2007, 1:09am UTC](https://community.cartalk.com/t/service-engine-light/5686/3 "2007-10-09T01:09:14Z")
Try disconnecting the negative battery terminal for a minute or two, then re-connect. This will allow the computer to re-boot and the light should go off. ---
**Author:** ![dmoore](https://avatars.discourse-cdn.com/v4/letter/d/35a633/32.png) [@dmoore](https://community.cartalk.com/u/dmoore)\ **Post date:** [October 9, 2007, 3:17pm UTC](https://community.cartalk.com/t/service-engine-light/5686/4 "2007-10-09T15:17:44Z")
The guy at Autozone is a jerk!! He said they cannot erase the code.