I have a 2006 Honda Civic Hybrid. About 6 weeks ago my check engine light came on and the thermostat code came up. Ok, no problem, my mechanic changed my thermostat. Since then, it has been back no less than 8 times because the codes keep coming back after 2 days. The car has never overheated and the temp always reads fine. All hoses have been changed. The second thermostat has been changed. The radiator has been checked for leaks. The head gasket is not blown. The thermostats have been checked for voltage compatibility. The engine block is reading within 1 degree of what the thermostats read with two different spot thermometers. My mechanic took it to a Honda Dealership after hours as one of his friends works there, and they couldnt find anything wrong with the car, other than the light still being on and giving out thermostat codes.

The car is a bit jumpy from stop with the AC on, but that has always been the case. Otherwise, everything is normal.

I have to have my inspection in less than 3 weeks, so any ideas about what this could be would be really appreciated. I absolutely cannot afford to replace my car for not passing inspection, especially as it is not actually giving me any problems outside of the ****ed light.

The codes given are P2183 ECT 2 Range and P0111 IAT Sensor 1 Circuit.

Thanks!

 

Not sure what you're talking about. Neither code indicates "thermostat code"

From the Honda service manual:

"If DTC P0111 is stored at the same time as DTC P2183, troubleshoot DTC P0111 first, then recheck for DTC P0111"

P0111:
Check for poor connections or loose terminals at ECT sensor 1/2 and the MAF sensor/IAT sensor
Follow a procedure to check for MAF/IAT sensor accurate operation with HDS
it fails to meet functional criteria, replace
Reset PCM
do the PCM idle learn procedure.
If P0111 returns, check for poor connections at the MAF/IAT sensor and PCM. repeat diags.

P2183 describes a similar procedure to establish ECT 2 sensor function and replace if it fails (but only AFTER P0111 has been resolved).

At no time does either code indicate the thermostat is an option.

P0125 is the ECT Sensor 1 Malfunctino/Slow Response code, and it can be tripped by a bad thermostat.

Sounds like either you have been given bad information, both your mechanic and his dealer friend are incompetent, or I'm just a code-reading idiot monkey RTFM.