Just as the title says, my engine temperature is reading "--- F". Is this a thermostat issue? Would it be covered under the 5 year powertrain warranty?

 

Do you also have a CEL?

Either thermostat or coolant temp sensor.

 

i had that problem like 2 months ago....for me it was the thermostat

 

Thermostat or coolant temp senosr. Call the dealer and see if either is covered under warranty.

 

funny thing is, I dont. I only noticed it last night.

 

afireinside7710,

I've included below a list of included and excluded components for the engine under the 5 year/100,000 mile powertrain warranty.

Best,
Sarah
GM Customer Service

Engine Coverage Includes: All internally lubricated parts, the entire pressurized fuel system (in-tank fuel pump, pressure lines, fuel rail(s), regulator, injectors and return line). Also included are all actuators and electrical components internal to the engine (i.e.: Active Fuel Management Valve Lifter Oil Manifold, etc.) as well as the Engine/Powertrain Control Module, module programming, cylinder head, block, timing gears, timing chain, timing cover, oil pump/oil pump housing, OHC carriers, valve covers, oil pan, seals, gaskets, manifolds, flywheel, water pump, harmonic balancer, engine mount, starter motor, turbocharger and supercharger. Timing belts are covered until the first scheduled maintenance interval.



Exclusions: Excluded from the powertrain coverage are sensors, wiring, connectors, engine radiator, coolant hoses, fans, coolant and heater core. Coverage on the engine cooling system begins at the inlet to the water pump and ends with the thermostat housing and/or outlet that attaches to the return hose. Also excluded are engine oil cooling hoses and radiators.

 

well guys, it magically 'fixed' itself this afternoon, so we will see how long it lasts. When it finally turned on, the temp was at 176 which I know is well within normal operating temperature so thats good, maybe it was just a short in the system (as I seem to be getting shocked by the car all the sudden)

 

spoke too soon. got a CEL with P0128 code. Looks like I will be getting the tstat replaced

 

Pretty easy replacement

 

I got another question. I currently still have the CEL (have not gotten the tstat replaced yet), however the temp gauge is working, and the AC also works. The temp reaches 171-176 instead of 190 after driving around for 10-15 minutes. Still think its the tstat or am I looking at something else

 

Everything might be working fine now. Eventually the CEL may go off if after so many drive cycles the reported fault doesnt-reoccoure. Id have to look up that fault in my manual to say for sure. Could be a Tstat sticking. I think its dumb that when the PCM detects a faulty Tsat that it sends a --- for coolant temp instead of whatever the temp is. but I didnt program it.

 

mine did the same came back on the went off again it was my thermostat got that fixed now new problem my fan dosen't kick on until i hit 220 and in the 7 years ive owned the car its never been above 200 what could that be

 

Here is what the GM Service Manual says about Code P128 for the 2.2L (L61) Engine.

An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the engine control module (ECM) for engine control and as an enabling criteria for some diagnostics.
The air flow coming into the engine is accumulated and used to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. if the coolant temperature does not increase normally or does not reach the regulating temperature of the tehermostat, the diagnostics that use ECT as enabling criteria may not run when expected.
This DTC will only run once per ignition cycle within the enabling conditions. If the ECM detects the calibrated amount ofairflow, vehicle speed and distance, and engine run time have been met, and the ECT has no met the minimum thermostat regulating temperature, DTC P0128 Sets.

Conditions for running the DTC:
DCSs P0101, P0102, P0103, P0112, P0113, Po117, P0118, P0502, P0503 are not set.
Startup ECT is less then 176F
IAT is more then 19F
Engine run time between 30 seconds and 30 minutes
Vehicle is driven more then 1/2 mile at more then 5mph
MAF is between 20-75 g/s, with average more then 30 g/s.

Conditions for setting the DTC:
The ECM Detects that
Calibrated amount of engine run time has been met
Calibrated amount of engine airflow has been met
Calibrated vehicle speed and distance have been met
Calibrated ECT of 176 has not been met.

Conditions for Clearing MIL/DTC
-3 Consecutive ignition cycles that the diagnostic runs and does not fail. (See conditions for running)
-A Current DTC last test failed clears when diagnostic runs and passes.
-A History DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
-Clear the MIL and DTC with scan tool.

Since your getting 171-176 your CEL will probably remain illumiated. Most likly your thermostat is faulty.

 

Sounds like your bad thermostat was preventing your engine from ever reaching 200F somehow.
According to my GM service manual for the 2.0L LSJ the fans come on at low speed at 223F and high speed at 230F.

Note: Custom tunes may change this.