OBD follow up

[Roger in Iowa]

Purchased cheapest reader from Harbor Freight. Cen-Tech,$27 plus tax after 20% off. Included book with codes.

Less than fifteen minutes after hooking it up had the code P0128 something about thermostat not getting engine to
temperature. Was a really cold day when light came on. Erased code and will see if it happens again. (thermostat
seems to be working as engine comes up to temp)

Dealer wanted $99 for an hour of diagnostics.
Thanks for all the input. Roger

 

[Oliver 500 Wa]

Something to keep in mind is that many vehicles use different sensors for coolant temp gauge versus the signal to the computer. A bad sensor to the computer could trigger this code despite the thermostat working and the engine actually being up to temp. This is where the OBDII testers that can read live data come in handy. You can read what the sensor says the temperature is and verify it against actual.

 

[Roger in Iowa]

Oliver, good thought. I can go into vehicle info and get digital temps for engine water, oil and trans to compare!
Especially if it happens again..

 

[Steve@Advance]

If it happens again, try a new thermostat.

That is a common failure. The thermostat fails to fully seat closed, the temp doesn't get up in time, the ECM sets the code.

 

[Bob]

(quoted from post at 15:55:35 04/08/20) If it happens again, try a new thermostat.

That is a common failure. The thermostat fails to fully seat closed, the temp doesn't get up in time, the ECM sets the code.

"The thermostat fails to fully seat closed, the temp doesn't get up in time, the ECM sets the code."

X 2 to that.

The odds are probably over 90% it's time for a new T-stat.

Sometimes (often) it's the simple things!

 

[Mike M]

Didn't you just get a brand new truck ? I hope you don't need the code reader for it.

 

[Roger in Iowa]

Mike, the 2011 Charger was having the trouble. It only has 141,+++ miles and only service has been oil changes and spark plugs (at 137000).

 

[brooktre]

I would give it time before replacing anything. I've reset many codes on my vehicles that never came back or came back a year later only to be reset again. Unless the code comes right back or you notice a performance issue I would wait.