Jul 4, 2025
Оfftopic Community
Оfftopic Community
Forums
New posts
Search forums
What's new
Featured content
New posts
New media
New media comments
New resources
New profile posts
Latest activity
Media
New media
New comments
Search media
Resources
Latest reviews
Search resources
Members
Current visitors
New profile posts
Search profile posts
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
iHav to Drive
European Imports
I don't know why my check engine light is on... Audi 1997 A4 Quattro (see details)?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="hondaguy" data-source="post: 1298658" data-attributes="member: 222331"><p>The On-Board Diagnosis (OBD II) is required to monitor engine temperature as part of the emissions monitoring. when a problem is detected that can lead to excessive emissions then by law the OBD II system has to turn on th check engine light.</p><p></p><p>The problem that is being detected on your car is that the engine temperature is running higher than it should. Hot engines produce more tailpipe emissions of an exhaust gas known as NOx (Oxides of Nitrogen). So the check engine light is on because the engine is running hotter than it should and more than likely producing excessive emissions.</p><p></p><p>The original term for this particular diagnosis was "thermostat monitoring" where the on-board diagnosis system monitored the opening and closing of the engine thermostat to regulate engine temperature. Different manufacturers use different terminology but essentially the check engine light is telling you that the engine thermostat isn't regulating the engine temperature as it should.</p><p></p><p>the problem is most likely with the thermostat for the cooling system but the conditon can also be caused by a low coolant level or restrictions in the cooling system. The odds say its the thermostat that's bad</p><p></p><p>hope that helps</p></blockquote><p></p>
[QUOTE="hondaguy, post: 1298658, member: 222331"] The On-Board Diagnosis (OBD II) is required to monitor engine temperature as part of the emissions monitoring. when a problem is detected that can lead to excessive emissions then by law the OBD II system has to turn on th check engine light. The problem that is being detected on your car is that the engine temperature is running higher than it should. Hot engines produce more tailpipe emissions of an exhaust gas known as NOx (Oxides of Nitrogen). So the check engine light is on because the engine is running hotter than it should and more than likely producing excessive emissions. The original term for this particular diagnosis was "thermostat monitoring" where the on-board diagnosis system monitored the opening and closing of the engine thermostat to regulate engine temperature. Different manufacturers use different terminology but essentially the check engine light is telling you that the engine thermostat isn't regulating the engine temperature as it should. the problem is most likely with the thermostat for the cooling system but the conditon can also be caused by a low coolant level or restrictions in the cooling system. The odds say its the thermostat that's bad hope that helps [/QUOTE]
Insert quotes…
Name
Verification
Please enable JavaScript to continue.
Loading…
Post reply
Top