2004 honda civic, temp gauge and tachometer stopped working, green key light came on, throttle not right?

You'll need to have the fault codes read out on the Gauge Control Module (PCU), ECM, the HVAC and the MICU. A scanner capable of reading into these controllers. Those "Code readers" or the ones at the auto part stores will not work, specially for Chassis code Cxxxx or Body code Bxxxx left alone the U codes.. The sub-model on the Civic determines in getting the right wiring diagram with the right colored wiring ..What's yours?

(Hybrid, Dx, Gx, Ex, Hx, Lx, Si or Hatch back?) You can do the "Hard reset" like you said by remove both battery cables and touch the cable's terminal ends together for about 30 minutes (Use one cable lead of the jump start cable set if you prefer to do) and see. But by doing so, the stored fault code(s) if any could be erased and make it harder for any technician to diagnose into the matter. So don't do it or do it AFTER all of the codes are scanned and recorded.

All gauges, indicators and dash illumination controlled by the CPU built-in the gauge assembly. The CPU receives the information and signals from the ECM via the multiplex control unit. Any light at all lit up on the dash cluster?

I would check the fuses first: Fuse # 2 (15A), Fuse # 3 (10A) and # 10 (7.5A). The fuses number might be differ as the sub-model was not indicate in your description. Make yourself a "Fist" and tap/ bump lightly on top of the IPC (instrument panel cluster) and see if the matter changing, if so, you may have a loose connection behind the dash.

When you have the codes read out. Let me know, depend on how many codes or if there is no communication between the scanner and the IPC's CPU or the Multiplex controllers: Most likely, the IPC has to be sent out for repair or replace. My Email: [email protected] Otherwise: Don't forget to close the question.

Thank you.

Hi what you need is a honda dealer to sort this out.