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Discussion Starter · #1 ·
2007 Cobalt with 2.2 liter. I was having a coolant temp not indicating in the DIC (-------) issue, i replaced the sensor and it cured it for a few days. I then replaced the sensor, coolant and thermostat. Its still not indicating in the DIC but now its also throwing a "POWER STEERING" and "ICE POSSIBLE" message in the DIC as well as no longer showing fuel economy, or any other information aside from mileage. Any ideas were to start? Im assumimg some kind of break in a data wire to the DIC??
 

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Seems you may have some,dirty connectors on your BCM. The DIC gets its info via the GM- lan from the BCM.

Try unplugging each connector on the BCM times to wipe any potential owing off of the connectors and let’s us know what you find out
 

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Discussion Starter · #3 ·
Seems you may have some,dirty connectors on your BCM. The DIC gets its info via the GM- lan from the BCM.

Try unplugging each connector on the BCM times to wipe any potential owing off of the connectors and let’s us know what you find out
I cycled all the connectors multiple times on BCM with no change. I assume the BCM gets its engine info from the ECM so i cycled the two connectors on the ECM and what i assume is the TCM (directy behind ecm) multiple times. Engine coolant temp is now indicating in my DIC. However im still getting the "POWER STEERING" message(appears to feel fine), none of the fuel economy or trip meters indicate anything besides dots (...........), Speedometer does not indicate. Odometer is still indicating.
 

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Discussion Starter · #4 ·
im going to check the TCM ground as it appears the TCM also tells the EPS information as well as the VSS for the speedo. And if im reading correctly the ground for the TCM is under on the transmission which did have a bunch of coolant run over it if thats the case perhaps excerbating a poor ground? Ill post my results.

"Circuit Description
The power steering control module (PSCM) receives a vehicle speed message via the serial data circuit from the powertrain control module (PCM), if equipped with a 2.0L engine (LSJ), or from the engine control module (ECM), if equipped with a 2.2L engine (L61). The ECM receives the vehicle speed message from the transmission control module (TCM), if equipped with an automatic transmission (MN5). The PSCM uses this vehicle speed message, and other inputs, to determine the desired amount of steering assist. At lower speeds, more assist is provided for easy turning during parking maneuvers. At higher speeds, less assist is provided for improved road feel and directional stability."
 

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Discussion Starter · #5 ·
I jumped the TCM case to good ground and all indicators resumed working, "POWER STEERING" message went away. I disconnected to verify and issues came back. Im going to investigate the ground and/or run a new ground. This appears to be the issue.
 

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Do a quick search for ground location images

 

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You may need to check the pesky grounds. I have seen where some people have found the ground wire clusters to be completely corroded. Basically rotting out the wires. The G105 ground seems to be a problem in many Cobalts, HHRs, and G5s. It may be because it’s location is exposed to moisture and road debris. It’s one I’ll be having a look at on my own car which may or may not be causing some transmission problems with my car.
 
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