I recently bought a used 2001 EX Coupe. It has several issues that I have to fix. The guage cluster backlights do not work ( I assume because of a bad aftermarket stereo install). I believe the guages themselves are working though. Because of this I have been monitoring the engine using the live data function of my OBD reader. The car has a slight head gasket leak that I am going to try and tackle this week. Because of the leak I have been watching my ETC temps closely. It made me nervous yesterday as I was in some traffic and noticed 230 degrees. The guage was mid range and no check engine light. The temps went down once I got moving. My questions are at what temp would the computer trigger a check engine light and what is the danger zone for ECT temps? Thank for any help. The car runs great even with these issues.

Ed

 

Have you checked the fuse for the cluster backlights?

What makes you believe the head gasket is blown?

Have you checked whether the radiator and condenser fans run? If not, this would cause the engine temp to rise only when the car is not moving. Also check the coolant levels in both the radiator and reservoir and then bleed the cooling system.

230F can be classified as overheating. Here are the temp specs for your cooling system controls:

 

Ron J

All fuses are good. On the head gasket, I smelled coolant leaking and had to keep adding some. Could not find any external leaks anywhere. Expansion tank would not flow back into the radiator. Ran pressure test on radiator and checked good. Ran chemical gas test on radiator and it checked good. Was told to hook up shop air to each cylinder at TDC and watch coolant level at radiator cap opening. Second cylinder tested, the water started coming up. Forget about all those other tests for Head Gasket failure and test it this way. Wasted a lot of time and got false results the other ways.

Ed

 

Have you voltage tested the backlight fuse with the light switch on to ensure that the fuse receives voltage and has voltage on both test tabs?

Nice diagnostics. Replace HG and go from there.

 

Also check whether the gauge cluster receives voltage from 15A dash fuse 2.

Do other dash lights outside the cluster work?

 

Ron,

Thanks, light problem will have to wait. Trying to work through the list of things that need tending to on this used car in order of importance. Had more issues than I thought (LOL). I still would like to find out at what tempeture the computer sets a fault code and turns on the Check Engine Light. I have seen some posts on the internet that said they have seen temps up to 260 degrees. That seems high and I think it would boil even with antifreeze in it at that temp.

Ed

 

Ron,

I have also been told that the temp guage is not a true guage. It is more of a on/off type guage. It reads normal (1/2 way) until it reaches a certain limit and then goes Full hot. It would not have cost anymore for them to put in a true guage that rose with the temp. That way you would notice that you were starting to run hot before it got too bad. Do you agree?

Ed

 

Based on the diagram below, I presume that CEL code P0116 would be set if the coolant temp rises above 212F.

I can't verify your statements about the cluster temp gauge, but it doesn't make much sense to me that it would work that way. My 97 and 00 Civic gauges work continuously from low to high. However, the 7th and 6th generation Civic temp gauges could operate differently.

Have you run the self diagnosis tests on your gauge cluster?

 

Ron,
The cluster works ok in self test. I believe someone has been into it though because the speedometer needle doesn't go to zero it stays at 15 mph when stopped and reads about that throught out its range. The Tach is about the same way and reads about 1500 high. It is like the needles were not put on right. We have a Shop in town that can repair and calibrate the cluster so I may go that route. The info on my OBD scanner reads correctly so it must be the cluster.

 

Had some bad wather so I switched over to working on the dash lights. I discovered the previous owner was not quite truthful (imagine that). I called him and asked if anybody had ever been into it and he said no. I pulled the cluster and half of the screws were missing. Made the job easier though. Took it apart and found burnt runs on the circuit board. Just like others have put on the forums. Cleaned it up and replaced the burnt runs with jumpers. Pulled out the aftermaket head unit and plugged in the cluster. Lights work fine now. I looked at the wiring for the radio and have not found the problem yet. There are two wires on the jumper plug for installing the stereo. one orange and the other orange / white. One is marked illumination. and one is marked dimmer. they are not connected to anything. I don't know if this was before the cluster burned up or someone went back in there and cut the wires after the cluster burnt. I want to make sure I don't re-burn my cluster now that I have it working. Any ideas? I have the radio wiring and the car wiring but I get a little confused when looking at it.