# 2000 Altima Coolant Temp Sensor Error



## Mlstrass (Apr 21, 2006)

I get a random SES light for the coolant temp sensor. I've replaced it 3 times now as the code comes back after a few weeks. It will also clear after a week or so, then come back a few weeks later. 

Car hesitates when cold and is hard to start when hot, only when the SES light is on. 

How do I troubleshoot the wiring for the CTS and ECM as it seems to be the CTS circuit, but not the actual sensor as I can't believe 3 in a row would be defective. 

Thanks for any help...


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## SPEEDO (Jun 9, 2003)

there 2 coolant temp sensors, one feeds the gauge and one feeds the ecu, are you sure you are replacing the correct one? Any more codes?


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## Mlstrass (Apr 21, 2006)

SPEEDO said:


> there 2 coolant temp sensors, one feeds the gauge and one feeds the ecu, are you sure you are replacing the correct one? Any more codes?


Yes the coolant temp sensor for the ecu located on back of the engine, not the temp sender for the gauge which is up front. 

That's the only code it throws...


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## rogoman (Dec 16, 2004)

Mlstrass said:


> How do I troubleshoot the wiring for the CTS and ECM as it seems to be the CTS circuit, but not the actual sensor as I can't believe 3 in a row would be defective.


You may have an intermittent harness connection or possibly a bad ground. Download an FSM from the following site:

Nissan and Infiniti Service Manuals


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## Mlstrass (Apr 21, 2006)

Thanks, just sent an email request for ID/password to download the manual.


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## 2000one (Aug 1, 2007)

My Altima's temperature reads normal when driving on the streets, but when I hit highways speeds (on the highway of course) my temperature drops like the engine somehow is cooler. The needle bounces up and down, which I know isn't right. Does yours do the same?


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## smj999smj (Jan 1, 2006)

One or both of you could have a stuck open thermostat.


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## Mlstrass (Apr 21, 2006)

The temp sender feeds the gauge. The temp sensor provides feedback to the ECU.


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