Trouble codes offer detailed info, glossing over the exact description leads to random changing of parts. Below is what I typed in another thread. The goal of all of this is to give people diagnostic tools that will help in solving future problems.


https://www.peachparts.com/shopforum/tech-help/396616-reving-up-down-code-p-1580-p0100.html

Detailed trouble code descriptions give information as to what the computer is seeing that it does not like. This is critical in forming a diagnostic strategy. Also, some trouble codes are caused by a failure of a part not listed in the trouble code.

Here are 7 generic OBD2 trouble codes related to the coolant temp sensor. Not all codes are used on every car.

Quote:

P0115 Engine Coolant Temperature Sensor Circuit 1 Malfunction P0116 Engine Coolant Temperature Sensor Circuit 1 Range/Performance Problem P0117 Engine Coolant Temperature Sensor Circuit 1 Low Input P0118 Engine Coolant Temperature Sensor Circuit 1 High Input P0119 Engine Coolant Temperature Sensor Circuit 1 Intermittent P011A Engine Coolant Temperature Sensor 1/2 Correlation P011B Engine Coolant Temperature/Intake Air Temperature Correlation Read more at: https://www.obd-codes.com/p01-codes Copyright OBD-Codes.com

P0116 could be caused by a stuck open thermostat or low coolant.

P0117 could be caused by the sensing wire being pinched to ground

P0118 could be caused by the sensing wire being broken , tied to power or bad plug contact.

P011B could be caused by an intake air sensor problem or someone leaving a trouble light next to the battery to keep it warm ( if the intake air temp sensor / intake duct is near by it will see a temp above engine temp. )

Somewhere in a factory shop manual there will be a detailed code description. This gives clues as what to test to perform. For coolant temp I'd be hanging a volt meter or scope on the coolant temp sensor wire and watching it.