thecca

Honda Civic 2004 LX automatic (coupe)

Hi there, this fall my alternator's voltage regulator gave up and the car ran on 17-18V for about 30 minutes (the time I got back to home...)

So I changed it for a new one + a new battery. Everything was fine, but then I realized my temperature gauge wasn't working...

Here's the thing : After a few minutes of riding, if I turn the key to off and turn if back to on, the gauge gets to it's actual temperature. If I don't, it stays down even if my car warms up. I'm thinking the signal from the ECT to the gauge isn't working ''constantly''?

Now, I've tried to put another ECT (temp sensor) and it didn't work. I read it could be the MCU (Multiplex Control Unit) OR the whole ECU. Someone told me that the ECT was sending the signal to the MCU and then transferring it to the temperature gauge, so my guess is that the MCU blew when the car was running on 17-18V? (well, the temperature part, because everything else is working on the car except this)

Can somebody help me with this? I'm trying to solve my issue without spending a fortune...

No one?

?

meandino

Having the same issue...

martpav

pickup a bluetooth ELM 327 from ebay for about $10, connect it to smartphone with free version of Torque or other program, check sensor output .. Done

thecca

What do you mean check sensor output?

The coolant temp sensor is fine... The problem is the MCU or the whole ECU... The signal isn't constant because the temperature gauge and the idle doesn't move when the engine warms. The signal is probably blocked in the MCU or something like that.

eviee1973

There is a link in the FAQ's to perform a self diagnostic check for your instrument cluster, try that and see if it is in your cluster, or a signal to cluster issue.