Kadorja

So on the way to work this morning my car displayed a message about coolant temp being to high and that the A/C was disabled. I felt the air coming out of the vent (A/C was never actually on) and it was ice cold. I took a glance at the coolant temp expecting it to be pegged and it was actually all the way down. The DIC also displayed "XXX."

Anyone have any ideas why? I figured the sensor is going bad or something happened to the wring. Car was driving normally and there was no way anything overheated. Coolant felt normal and the overflow reservoir was at the normal level.

USAF

Check the fluid level.

USAF

Kadorja

Fluid level was perfect after shutting the car down. The shop it was at prior used a purge kit to fill and purge all the air out of the system so I have no doubt it's good.

ls1wolf

Had same problem when I did my cam last year. There's a small 18 gage wire that is behind the alternator. I bet ya it has been split or pulled. It's a small enough wire that it happened and you didn't even mean to.

Kadorja

So I reseated the connector and started the car up with the same issue. Pulled out the code reader and had some old codes in the history. 0 new ones. I cleared the old codes and immediately the gauge and DIC display worked. Started the car up and it worked fine.

Possibly have air in the system so I may pull the cap and let it run for a minute to purge any air.

subfloor@centurytrans

The gauge is bad, don't waste your time looking for non-existent air in the system.

2k Cobra

Your car is doing ****..

I would go with the rest. Bad sensor or wiring. 2k

Kadorja

I can see possibly the sensor going bad. Resetting electronics does interesting things but usually if a sensor is bad its not going to change the result.

From what I understand about C6s is that the signal is split to the DIC and to the gauge cluster so if the gauge went out the DIC would still work.

I got plenty of miles to put on the new engine before taking it back to the shop so if the sensor is bad ill just order one and swap it out before hitting the dyno again.

6Speeder

Are you running a 160 degree thermostat? It can cause the coolant temp to not come up to temp as fast as the ECM predicts. Your symptoms match what the ECM does.

tennblkc6

i know there are many ppl that have installed 160* stats so is it common for this to happen for those that have installed them?

0Anthony @ LGMotorsports

There is either a cut in the wire, or the sensor is bad...

Could be the dash but I would check the above two first.

ls1wolf

Apparently no one read my post. Go figure.

Kadorja

Yes but the car has been tuned for the new thermostat (among other things) and it has run like that for quite a few months with no issues.

I read it but I didn't notice anything wrong with the wiring. That was my first guess considering how close it sits to the long tube headers.

ls1wolf

The wire runs along the wrapped "loom". Take the tape off. My wire was split under the tape.

6Speeder

It's the thermostat. Usually happens when it's cold outside and you get up to highway speed quickly. Have your tuner turn off the engine undertemp code, all is well.

Code P0128:
When is the code detected?
If the Powertrain Control Module (PCM) detects the calibrated amount of air flow and engine run time have been met, and the Engine Coolant Temperature (ECT) has not met the minimum thermostat regulating temperature, the code P0128 will set.

Read more: http://engine-codes.com/p0128_chevro...#ixzz2yPd4PkIg