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High idle and no temp reading

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Old May 11, 2025 | 02:22 PM
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Verify the wiring between the sensor, and PCM.
 
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Old Jun 10, 2025 | 06:34 PM
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Originally Posted by HeyYou
Verify the wiring between the sensor, and PCM.
would you happen to know what pin I am looking for?
 
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Old Jun 10, 2025 | 07:55 PM
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Originally Posted by Nkirby2002
would you happen to know what pin I am looking for?
Download the service manual for your truck from here. Wiring diagrams are in section 8W. Two wire sensor, one is five volt feed FROM the pcm, the other will be return signal TO the PCM.
 
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Old Apr 11, 2026 | 09:55 AM
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Originally Posted by HeyYou
Download the service manual for your truck from here. Wiring diagrams are in section 8W. Two wire sensor, one is five volt feed FROM the pcm, the other will be return signal TO the PCM.
I’ve checked the wiring going up to the connector I’m getting 4.86signal and 0.1-0 to the ground side as far as I can see I have no breaks I have put a new pigtail connector on it to rule out wiring close to the engine by temp sensor and the trucks still reading 145
 
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Old Apr 11, 2026 | 08:15 PM
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Bad sensor?
 
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Old Apr 12, 2026 | 01:51 AM
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Check the resistance across the pins of the ECT sensor, it should be ballpark in this table:

99 should be a 24V with an ECM so check resistance across pins 14 and 11 at the ECM if the above checks out.
 
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Old Apr 12, 2026 | 11:02 AM
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Originally Posted by HeyYou
Bad sensor?
not sure as I have replaced it already but I will test again to make sure
 
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Old Apr 13, 2026 | 06:04 PM
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Originally Posted by DerTruck
Check the resistance across the pins of the ECT sensor, it should be ballpark in this table:

99 should be a 24V with an ECM so check resistance across pins 14 and 11 at the ECM if the above checks out.
everything on the sensor seems to add up and I checked the resistance which I believe is good at 2.36 when truck is cold
 
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Old Apr 13, 2026 | 06:09 PM
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Originally Posted by HeyYou
Bad sensor?
sensor is testing good still
 
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Old Apr 14, 2026 | 07:30 AM
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Have a scanner? Is the PCM seeing a temp reading?
 
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