The temperature gauge is not working and the check engine light is on?

HEATHER7885

MEMBER
2008 PONTIAC G6
3.5L
V6
AUTOMATIC
205,000 MILES

For the past 4 years, the temperature gauge will only work in the warm months that I use my A/C. It will not work in the winter months while I run my heat. Just a few days ago, the temperature gauge quit working. I replaced the CTS thinking that was the problem. My temperature gauge is still not working, and the check engine light is on. Can someone guide me in the right direction of what it could be?

Monday, July 17th, 2023 AT 2:46 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,101 POSTS

Hi,

What you should do is scan the can-bus. CAN stands for controller area network. Basically, the different modules are tied together via a few wires. This will retrieve codes regardless of the module storing them.

Here is a link showing how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

If you look below, I attached a pic from the wiring schematic. Note there are two wires to the sensor you replaced. One is a 5v reference signal and the other is a low reference or ground. If possible, check the yellow wire with a multimeter to see if there is power to it. If there is, check for a ground on the opposite wire. The key will need to be in the run position when you do this.

Let me know the results.

Take care,

Joe

See pic below. Note: Make sure to check the connector and connector pins and wiring for damage.

Image (Click to make bigger)