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Hey guys I'm back again I'm trying to get some help with this problem that I'm having. My Radiator fan keeps coming on even with the engine cold, it eventually turns off few minutes later after ignition off... but I can't understand why it keeps coming on I thought It was my coolant temperature sensor and I replace that, but, keeps still coming on it didn't fix the problem. I tried to to switch around to relay to see if any difference, but that didn't solve it so I'm just confused right now just need to get some help thanks
 

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P0117 means the Engine Coolant Temp (ECT) sensor is providing an out of spec voltage back to the PCM.
This could be the sensor itself or a wiring fault.
The resistance in the sensor is inversely proportional to the temperature... high ohms is low temp low ohms is high temp.
Check the ECT reading on your scan tool vs an infrared thermometer.
ECT temp from the PCM should drop to extremely cold when you unplug the sensor.
You can check for intermittent connection at the sensor by wiggling the wiring at the ECT sensor. Visual checks are still a valid step... unplug the connector and look for green or white corrosion on the terminals.
 

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Discussion Starter #3
P0117 means the Engine Coolant Temp (ECT) sensor is providing an out of spec voltage back to the PCM.
This could be the sensor itself or a wiring fault.
The resistance in the sensor is inversely proportional to the temperature... high ohms is low temp low ohms is high temp.
Check the ECT reading on your scan tool vs an infrared thermometer.
ECT temp from the PCM should drop to extremely cold when you unplug the sensor.
You can check for intermittent connection at the sensor by wiggling the wiring at the ECT sensor. Visual checks are still a valid step... unplug the connector and look for green or white corrosion on the terminals.
I have checked the Coolant temp Sensor Resistance and Continuity and it Checks Out, but ordered a new one anyway, Just to be on the safe side, I have tested the other side (Dash/PCM) and got the 5V that should be there. My next quest is to find a way to test the Dash Coolant Temp gauge, I think that might be the culprit, from what I've gathered so far, It also mimics the symptom of bad ECT Sensor and probably the reason why it keeps thinking that its overheating and keeps keeping the fan on a little longer that it should.

Anyway, can You/anyone please point Me to any info about testing the dash Coolant temp sensor on this cars?
Thanks.
 

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what up pimp...if you already changed the ECT you got a wiring issue somewhere. Check your PCM in the air intake box...clean all dust out...mice tend to live in these small compartments and mess the impala all up. Having experienced this right at home bruh. especially in the winter...check all of your PCM wiring. I changed a whole fuel injector...due to a bad pcm wiring and i had to do was re wire the corroded part. Also, your ECT ground shares a ground with your MAP sensor. Fans continuously run only due to ECT malfunction which controls the fan HIGH speed. if the ECT is always grounding out then the fan relay switch will always click on. Now you know the relays are good. experienced this as well. even if your gauge move the ECT can issue a wrong reading back to the PCM then goes back to the gauge to reflecting the variable when it should be a slow fixed rise. A OBD 2 will pinpoint temps differences
 

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what up pimp...if you already changed the ECT you got a wiring issue somewhere. Check your PCM in the air intake box...clean all dust out...mice tend to live in these small compartments and mess the impala all up. Having experienced this right at home bruh. especially in the winter...check all of your PCM wiring. I changed a whole fuel injector...due to a bad pcm wiring and i had to do was re wire the corroded part. Also, your ECT ground shares a ground with your MAP sensor. Fans continuously run only due to ECT malfunction which controls the fan HIGH speed. if the ECT is always grounding out then the fan relay switch will always click on. Now you know the relays are good. experienced this as well. even if your gauge move the ECT can issue a wrong reading back to the PCM then goes back to the gauge to reflecting the variable when it should be a slow fixed rise. A OBD 2 will pinpoint temps differences
Bruh, I suspected that too and I have done all that, I have removed the PCM, Cleaned and Checked all the wires for wear/corrosion, everything is nice and tidy there, just a lot of dust and dirt, but, nothing seemed out of place. I'm just tired of battling with this thing, I have changed the ECT multiple times, No Change, and Just today, I tried replacing the map sensor still no change.
But, I see You do some electrical wiring, and You're in My area, Can You help? Are You an Electrician?
 

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Bruh, I suspected that too and I have done all that, I have removed the PCM, Cleaned and Checked all the wires for wear/corrosion, everything is nice and tidy there, just a lot of dust and dirt, but, nothing seemed out of place. I'm just tired of battling with this thing, I have changed the ECT multiple times, No Change, and Just today, I tried replacing the map sensor still no change.
But, I see You do some electrical wiring, and You're in My area, Can You help? Are You an Electrician?
 

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If you're getting an "engine overheating" or "engine overheating power reduced" message or the like on your DIC in the cluster it's not the instrument cluster.
These vehicles aren't your fathers 1980 Buick with completely analog gauges.
In most of the GM vehicles of the 2005 vintage the instrument cluster is completely digital. The processor in the cluster gets the temperature info from the ECM/PCM via the serial or CAN databuss and decodes it into a position to drive the stepper motor in the gauge. If the gauge stepper motor is sticky the gauge will be out of whack. The DIC will only show a complaint message if the ECM/PCM is sending it a request over the databuss for that message to be displayed.

If you have access to a scope you can view the CTS ground and signal lines as you're driving to see whether there's an issue with the wiring.
Since overheating is usually low ohmage from the temp sensor a slight intermittent short in the wires to and from the ECM/PCM could cause your troubles.
 
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