Help!! Coolant Temp xxx F

[DGVETTE]

I have had my 2004 Coupe for about 10 months without any problems. It had 13000 mi. when I bought it and it has 15075 mi. on it today. Since it is a 6sp manual transmission I installed the CAGS Skip Shift kit today. I disconnected the battery per the instructions. Installation was simple with no problems until I took car for short test drive to check 1 to 4 shift function. After short time I noticed the coolant temp gauge was pegged and the DIC readout was "COOLANT TEMP xxx F". I stopped car and could see no indication of coolant loss or engine overheat. I suspected a gauge problem. After letting car sit with motor off for a few minutes the temp gauge reads normal and the DIC reads 195-205 degree range. But soon after starting engine the temp would go to maxx on both gauges.
The only "C" code I have is a P0116 C. There are several other H codes which decode to Defogger Relay, Rh and Lh DRL, Backup Lamp, Loss of Comm. with BCM, etc. I have not cleared the codes, this is first time I have pulled codes on this car.
I can't find the P0116 code in my list but other searchs seem to indicate a coolant sensor problem. Does any one have more info on this code? Did I ruin a sensor?
Did disconnecting the battery create this situation? Did I not get the cable back on battery properly and tight enough? I only disconnected the neg/black cable. I can't see how installing the CAGS Skip Shift kit could cause this and I have not removed it yet. Should I put the 1 to 4 shift back to normal?

Any ideas???

 

[DRTH VTR]

Someone with better knowledge than I have will come along soon. Failure of the coolant temperature sending unit is a common problem. I do not know whether that is what is wrong with your car, but it would not surprise me. I did find a DTC that matches yours:

DTC P0116 Engine Coolant Temperature (ECT) Sensor Performance.

The "C" means it is a current problem, rather than a historical code.

You did not cause this problem.

 

[gmjunkie]

Someone with better knowledge than I have will come along soon. Failure of the coolant temperature sending unit is a common problem. I do not know whether that is what is wrong with your car, but it would not surprise me. I did find a DTC that matches yours:

DTC P0116 Engine Coolant Temperature (ECT) Sensor Performance.

The "C" means it is a current problem, rather than a historical code.

You did not cause this problem.

I agree!!!!

 

[DGVETTE]

Battery Condition???

I find reference to a lot of battery problems while searching, so I checked mine. It appears to be the original battery, about 4 yrs old now. The DIC will read 11.9 Volt with motor not running where my multimeter will read 12.2 volts at battery posts. This seems low for a battery that had car running within last 5 to 6 hours. The DIC will read 13+ volts with engine running.

The temp after couple hours was 154 degrees but maxxed the gauge and readout within seconds after starting motor. Something is definitely giving a false reading.

 

[DRTH VTR]

I think that you have two unrelated issues.

My Corvette starts having electronic gremlins when my battery gets below 12.3-12.4 volts. I am on my third battery on a 2002 Corvette.

But I think that you also have a bad temperature sending unit.

 

[DGVETTE]

Update: Day 2

I took car for 3 short trips today and the temp was normal. It was steady 194-196 degrees at 45 mph with outside temp of 80 degrees. Don't know what happened yesterday so I'll watch temp closely and keep my fingers crossed?? I hope it was only gauge malfunction and the engine did not actually reach those temperatures.
:confused

 

[zagger]

Check inside the radiator shroud for any trash. You might have sucked in a bag or something and it fell out or shifted allowing airflow again.

 

[LT4man]

Any time you disconnect the battery, disconnect the negative cable first and then disconnect the positive cable. When you reattach them, connect the positive one first, then the negative.

This had nothing to do with your problem. Just the proper way to disconnect and reconnect the cables.

SAVE THE

 

[c4c5specialist]

HI there,
Your cluster can be recalibrated for the correct voltage readings.
Sometimes they are a little off.
As for the sensor, this is located drivers side front of the cylinder head, directly below your alternator.
Its a 2 pin connector.
Disconnect it just to make sure the sensor isnt leaking coolant into the connector.
If so, replace the sensor, but personally, it would be recommended to replace it anyway.
Make sure the connector terminals are NOT spread apart, creating a shorted sensor reading.
Allthebest, c4c5

 

[Mr. Lucky]

Here is some further information on that code for your 2004.

GL!

 

[DGVETTE]

Here is some further information on that code for your 2004.

GL!

Mr. Lucky. Thanks for the link.

That was good info on operation of the Engine Coolant Sensor and the P0116 code. In my situation the hot engine temp vs the intake air temp and disconnecting the battery may have confused the PCM. The temps would be outside the 27 degree difference. The overnight 10hr cooldown/reset period allowed the PCM to resynch actual and expected engine temp values with intake air/ambient temp value.
The temperature is functioning normally now, even during stop/go traffic and extended idling periods.


Thanks to everyone.