Help please! Electrical Gremlins Invade Elvis...
Platinum Member
Joined: 04-09-2006
Posts: 7,043
From: Vancouver, BC, Canada
I don't think it is as bad as you think - read my comments interspersed with your notes. I think you are looking at a single cause of the problem - ie: the thermostat - read on:
As noted above, many of the problem symptoms I suspect are inter-related - and are generated by a faulty engine termostat. See some of the other threads where the thermostat replacement has been covered:
https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/
https://www.chevyhhr.net/forums/problems-service-repairs-42/heat-gauge-ac-not-working-all-sudden-30481/ (don't get sidetracked with the discussion about diodes!!!)
then again, I may be wrong
but that is where I would start.
Best of luck.
1 – Temp Gauge/Readout – Twice, the Engine Coolant Temperature gauge reads zero after the car was fully warmed. I checked the DIC display below the speedo, and under Temp it read “ ----“. This lasts for about a day (and overnight), and several starts, before it begins reading again like normal.
First step - Check the thermostat - sounds like it is stuck open causing it to run too cool (does not warm up fully) - the gauge will drop to the bottom ("zero" as you call it), and the digital display will show "----"
Dependant on the outside temp, driving cycles etc., as well as how badly the thermostat is broken, the condition may clear for a day or even a week or more, but will return. It may or maynot generate an ECL condition, and it may or maynot shutdown the A/C.
2 – Tire Pressure Warning - At the same time as the temp gauge going flat, the tire pressure sensor warning message appears on the multifunction display saying “SVC Tire Monitor” and the orange tire shaped Tire Pressure Light warning (lower right instrument panel) flashes and then stays on steady. When I check the display readout for tire pressure, it reads (all or multiples) “---- PSI“, though it will usually later go back to reading pressure again, though the orange Tire Pressure Light light stays illuminated. Yesterday all four read “----“ at once. If I stop and shut the car off and back on, it will clear. The actual tire pressure is just fine when I check.
Perhaps ChevyMgr can comment on this - I'd suspect it is triggered by the thermostat condition, but I have been wrong before
3- A/C - A few miles after the temp gauge goes flat, the A/C stops blowing cold. The system works fine, except obviously the compressor is not running. My service guy at the dealer says that makes sense, as when the temp gauge stops reading, the computer tells to A/C to shut down as the car might possibly be overheating (since it cannot tell). The A/C comes back on normally after the temp gauge rebounds. It has happened twice now, just like the service guys said.
as above - Check the thermostat - sounds like it is stuck open causing it to run too cool (does not warm up fully) - and it then prevents the A/C from operating during certain operating conditions
4 – ESC Warning Light – The stability control light came on twice yesterday, and then went off on its own.
5 - OBD II Check Engine Light – The check engine light came on yesterday, and is still illuminated today. No, I have changed nothing on the car any time recently, and the air filter is of a non-oiled variety in the GMPP intake (in the car for a year).
You need to download the code - I suspect it likely will indicate that the engine is running too cool (code 128) due to the thermostat
6 – A/C Compressor shudder – I noticed today after the A/C came back on, that if I cycle the A/C button, the car shudders hard at idle when I cut on the compressor with the A/C switch. It didn’t seem to do that before to this degree.
see above reference to the A/C - I suspect they are related.
7- Remote Start – My remote start will not start Elvis today. It acknowledges that I have asked it start by flashing the light, but it refuses to crank the engine. This is a new issue today.
Do y’all remember the wartime Bugs Bunny episode where the “gremlin” is in the airplane? I think the gremlin has moved on to Elvis now. Uh-oh! I could really use some advice here. The dealer thinks it may be a bad ground somewhere, but cannot find it if everything is working. Of course, the car is now working again before Monday morning when the service department opens. I am wondering about a bad battery as well. I have had two friends (one Mustang and one BMW) with really whacky electrical problems, that were eventually traced to “traveling shorts” in a battery. I am also wondering about the fuse box. Any help would be greatly appreciated and happily acknowledged here on the boards.
God Bless and Best wishes, Marc
First step - Check the thermostat - sounds like it is stuck open causing it to run too cool (does not warm up fully) - the gauge will drop to the bottom ("zero" as you call it), and the digital display will show "----"
Dependant on the outside temp, driving cycles etc., as well as how badly the thermostat is broken, the condition may clear for a day or even a week or more, but will return. It may or maynot generate an ECL condition, and it may or maynot shutdown the A/C.
2 – Tire Pressure Warning - At the same time as the temp gauge going flat, the tire pressure sensor warning message appears on the multifunction display saying “SVC Tire Monitor” and the orange tire shaped Tire Pressure Light warning (lower right instrument panel) flashes and then stays on steady. When I check the display readout for tire pressure, it reads (all or multiples) “---- PSI“, though it will usually later go back to reading pressure again, though the orange Tire Pressure Light light stays illuminated. Yesterday all four read “----“ at once. If I stop and shut the car off and back on, it will clear. The actual tire pressure is just fine when I check.
Perhaps ChevyMgr can comment on this - I'd suspect it is triggered by the thermostat condition, but I have been wrong before
3- A/C - A few miles after the temp gauge goes flat, the A/C stops blowing cold. The system works fine, except obviously the compressor is not running. My service guy at the dealer says that makes sense, as when the temp gauge stops reading, the computer tells to A/C to shut down as the car might possibly be overheating (since it cannot tell). The A/C comes back on normally after the temp gauge rebounds. It has happened twice now, just like the service guys said.
as above - Check the thermostat - sounds like it is stuck open causing it to run too cool (does not warm up fully) - and it then prevents the A/C from operating during certain operating conditions
4 – ESC Warning Light – The stability control light came on twice yesterday, and then went off on its own.
5 - OBD II Check Engine Light – The check engine light came on yesterday, and is still illuminated today. No, I have changed nothing on the car any time recently, and the air filter is of a non-oiled variety in the GMPP intake (in the car for a year).
You need to download the code - I suspect it likely will indicate that the engine is running too cool (code 128) due to the thermostat
6 – A/C Compressor shudder – I noticed today after the A/C came back on, that if I cycle the A/C button, the car shudders hard at idle when I cut on the compressor with the A/C switch. It didn’t seem to do that before to this degree.
see above reference to the A/C - I suspect they are related.
7- Remote Start – My remote start will not start Elvis today. It acknowledges that I have asked it start by flashing the light, but it refuses to crank the engine. This is a new issue today.
Do y’all remember the wartime Bugs Bunny episode where the “gremlin” is in the airplane? I think the gremlin has moved on to Elvis now. Uh-oh! I could really use some advice here. The dealer thinks it may be a bad ground somewhere, but cannot find it if everything is working. Of course, the car is now working again before Monday morning when the service department opens. I am wondering about a bad battery as well. I have had two friends (one Mustang and one BMW) with really whacky electrical problems, that were eventually traced to “traveling shorts” in a battery. I am also wondering about the fuse box. Any help would be greatly appreciated and happily acknowledged here on the boards.
God Bless and Best wishes, MarcAs noted above, many of the problem symptoms I suspect are inter-related - and are generated by a faulty engine termostat. See some of the other threads where the thermostat replacement has been covered:
https://www.chevyhhr.net/forums/how-tutorial-library-21/how-save-%24350-00-thermostat-replacement-2-4l-p0128-24493/
https://www.chevyhhr.net/forums/problems-service-repairs-42/heat-gauge-ac-not-working-all-sudden-30481/ (don't get sidetracked with the discussion about diodes!!!)
then again, I may be wrong
but that is where I would start. Best of luck.
Platinum Member
Joined: 01-09-2007
Posts: 16,081
From: SE USA
"as above - Check the thermostat - sounds like it is stuck open causing it to run too cool (does not warm up fully) - and it then prevents the A/C from operating during certain operating conditions"
Actually the thermostat helps slow the coolant in the radiator, to allow air to cool it. Try it sometime with no thermostat, & you will see.
As far as the A/C, it could be freezing outside & if you switch it on, it should still work fine.
Actually the thermostat helps slow the coolant in the radiator, to allow air to cool it. Try it sometime with no thermostat, & you will see.
As far as the A/C, it could be freezing outside & if you switch it on, it should still work fine.
Platinum Member
Joined: 04-09-2006
Posts: 7,043
From: Vancouver, BC, Canada
"as above - Check the thermostat - sounds like it is stuck open causing it to run too cool (does not warm up fully) - and it then prevents the A/C from operating during certain operating conditions"
"Actually the thermostat helps slow the coolant in the radiator, to allow air to cool it. Try it sometime with no thermostat, & you will see. "
Exactly - that's what I was saying (sort of) - with the thermostat stuck open, the vehicle will be slow to warm up. The computer detects that it is not coming up to temperature fast enough, and triggers the ECL if conditions are right. However, if it doen't meet the exact conditions to trigger the ECL, the temp gauge drops to the bottom ("zero") and the digital display reads "----" and no ECL is triggered. This has been covered in other posts better than I can explain here.
"As far as the A/C, it could be freezing outside & if you switch it on, it should still work fine.
"Actually the thermostat helps slow the coolant in the radiator, to allow air to cool it. Try it sometime with no thermostat, & you will see. "
Exactly - that's what I was saying (sort of) - with the thermostat stuck open, the vehicle will be slow to warm up. The computer detects that it is not coming up to temperature fast enough, and triggers the ECL if conditions are right. However, if it doen't meet the exact conditions to trigger the ECL, the temp gauge drops to the bottom ("zero") and the digital display reads "----" and no ECL is triggered. This has been covered in other posts better than I can explain here.
"As far as the A/C, it could be freezing outside & if you switch it on, it should still work fine.
You totally missed what I was saying - the fact the A/C doesn't come on in this situation is nothing to do with the outside temperature - it is due to the computer disabling the A/C because the car is running in an under temperature condition in the cooling system (thermostat stuck open).
I'm saying this from experience with my 2.4L - periodically my temp gauge would bottom out, the digital display would read "----", sometimes accompanied with an ECL being triggered, and sometimes accompanied with the A/C being disabled. The problem was traced to the coolant thermostat being stuck partly open causing the vehicle to be slow to warm up. Replacing the thermostat addressed all the problems and no problem reoccurred since (a good 15K miles ago).
Note: as some other posts noted, my dealer wanted $350 to replace the thermostat - one of the links I posted above describes how to do it yourself and save a few $'s.
cheers
Platinum Member
Joined: 04-09-2006
Posts: 7,043
From: Vancouver, BC, Canada
Founding Member
Joined: 11-23-2007
Posts: 8,210
From: Texas
Whopper has gotten you on the right trail for the fix. A thermostat should fixe everything except the TPMS light and the remote start, unless the TPMS light goes away, then the remote start will go back to working.
Platinum Member
Joined: 04-09-2006
Posts: 7,043
From: Vancouver, BC, Canada
I don't know. But it would make sense. Bet you are right.