strange message on driver display
Thread Starter
Intermediate
Joined: Nov 2010
Posts: 46
Likes: 0
From: Southlake Texas
strange message on driver display
Ok here is a strange one. 2011 ZR1, getting a message : Engine Hot A/C off- I have checked the engine temp with a temp gauge and all is normal. Tried clearing message with battery disconnect but it comes back. Dealer (ha!) claims never seen this message before. No trouble codes are thrown. Any ideas??
Thread Starter
Intermediate
Joined: Nov 2010
Posts: 46
Likes: 0
From: Southlake Texas
When this message appears, the temp gauge on the dash goes to zero, as if the car were off. The A/C indeed does not work when this message appears. Using an infrared temp tester the engine shows 199-200 degrees and very little difference in pre thermostat and post thermostat readings. The closest dealer, Classic Chevrolet as I said does not have a clue but wants to charge me $100 plus to do a "diagnostic test". My fear is that they will simply disconnect the battery like I did and the message will go away and tell me it is "fixed". Then as I said, after a couple of start/stop cycles, the message will come back! I bought this car new and this is the ONLY issue I have ever had. Driving me crazy. As you may know, the ZR1 does not use a coolant sensor so a simple replacement is a no go. Thanks for your insight.
Thread Starter
Intermediate
Joined: Nov 2010
Posts: 46
Likes: 0
From: Southlake Texas
Thanks for your response. The ZR1 does not have a temperature sensor in the traditional sense. It uses a variety of inputs to determine the engine coolant temperature (according to factory service manual). No codes are set when this message shows up. I found one other member who reported this same message in 2017 so I am hoping to hear back from him.
Instructor
Joined: Sep 2015
Posts: 167
Likes: 33
From: TN
I was curious about your comment that the LS9 doesn't have an engine coolant temp sensor.
i think it does, I think it should be in the head, above cylinder 1. kind of seems like it should be a few inches above the cylinder 1 spark plug. personally i would start by replacing that sensor, or at least checking the connector and wiring for problems.
EDIT: read diagnostic trouble codes, even if the check engine light is off, that doesn't mean that it didn't log something in history.
i think it does, I think it should be in the head, above cylinder 1. kind of seems like it should be a few inches above the cylinder 1 spark plug. personally i would start by replacing that sensor, or at least checking the connector and wiring for problems.
EDIT: read diagnostic trouble codes, even if the check engine light is off, that doesn't mean that it didn't log something in history.
Last edited by luka2sb; Oct 23, 2019 at 11:00 AM.
Safety Car
Joined: May 2011
Posts: 3,807
Likes: 508
From: Oshawa, Ontario
I believe that message is related to data received from your HVAC control module.I had the message appear on DIC at least once but it cleared on its own.I have never had an issue with my HVAC control module but I think I may have read on here where others on here have had this issue when HVAC module was failing
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