coolant temp sensor that talks to ecu part number location (1 Viewer)

Joined
Jul 20, 2014
Messages
445
For 1995.....

There are a couple of coolant sensors from my searching. I need to change the one that talks to the ecu and a part number would be awesome too.

Code p0125 and running rough no power under 3k rpm intermittently. Thanks!
 
Joined
Apr 5, 2006
Messages
791
Location
Canyon Lake, TX
The code may be a sign of a problem, but not the problem. If the engine does not warm up, it stays in open loop operation, and drives down the road as if you were driving it first thing in the morning. It ignores other sensors, and runs on a preset program for fuel trim until the temps come up. It should run fine. People who run around with their "check engine light" on are also running in this open loop mode all day long with out any power loss. It just doesn't get you very good gas milage.

Because yours is running poorly intermittently, it would seem there is another problem. Does the temp guage come up to normal? Can you get a scanner to read the temp as the ECU is seeing it?

I have had this code a few times when staying up in the mountains, and I basically coast down hill for 45 minutes to get back to pavement. I don't use hardly any gas pedal, and it is already cold from the morning temps. The CEL comes on, but goes out the next time I start the engine. Engine runs fine the entire time.
 
Joined
Jul 20, 2014
Messages
445
Thanks for the reply......Did you ever track down the problem?


I'm really frustrated with this situation at this point and the truck is running fine sometimes, and terrible especially after I disconnect the battery. I read in another thread that this sensor can actually shut the fuel pump down? It says it can cause misfire, rough idle, and general poor running.

I'm ready to get this thing fixed so I can enjoy it again. Does anyone know where that sensor is?
 
Joined
Jul 2, 2003
Messages
2,419
Location
Trumansburg, New York
You should do a search of this forum (80 series tech) for P0125. You most likely have a bad #1 O2 sensor or the harness/wiring may be damaged. It would be very helpful to know if your coolant temperature is registering on your dash gauge. Most likely your coolant temps are normal but the lack of input from the O2 sensor won't let it get out of closed loop; hence the P0125. If you have over 150K miles on your O2 sensors this might be a good place to start. That and purchasing an Ultragauge or Scangauge. Good luck.
 
Joined
Jul 20, 2014
Messages
445
The gauge on the dash shows right in the middle, except for one time over the weekend before this all started and it dropped to about a quarter of the gauge for a few minutes and rose back up.

I had code P0170 and cleaned up the check valves on the charcoal canister and replaced charcoal, new plugs, replaced a few vaccuum hoses. I had high tank pressure, after the job it was running fantastic, starting right back up, I was out doing my victory lap when I pulled in the gas station and unhooked the battery to clear the CEL. As soon as I fired it up, it started running terribly again!
 
Joined
Jul 20, 2014
Messages
445
You should do a search of this forum (80 series tech) for P0125. You most likely have a bad #1 O2 sensor or the harness/wiring may be damaged. It would be very helpful to know if your coolant temperature is registering on your dash gauge. Most likely your coolant temps are normal but the lack of input from the O2 sensor won't let it get out of closed loop; hence the P0125. If you have over 150K miles on your O2 sensors this might be a good place to start. That and purchasing an Ultragauge or Scangauge. Good luck.


Would the O2 sensor make it run like it was starving for fuel? That's what it feels like.
 
Joined
Jul 2, 2003
Messages
2,419
Location
Trumansburg, New York
diag_2bPgab.png
 
Joined
Jul 20, 2014
Messages
445
Solid, thank you.

I'm thinking about just switching them to see if the condition improves, the part numbers are the same.
 
Joined
Jul 20, 2014
Messages
445
The part numbers are not the same for a 1995-1997 1FZ



I was given bad information then....... glad I didn't go out there and try to switch them, haha.

would you mind providing them if you have handy?
 
Joined
Apr 5, 2006
Messages
791
Location
Canyon Lake, TX
Thanks for the reply......Did you ever track down the problem?

There is no "problem" for me. The reason it throws the code is because the outside air is so cold AND I am basically idling down a long cold hill for 45 minutes. The engine does not produce enough heat to warm up and the computer times out. It must (I guess) have an internal clock inside that says the engine should have come up to operating temp in "X" amount of minutes. I must go over that time.

Once I start driving, it comes up to temp, but the CEL stays on until it is resets itself by way of a off/on cycle.

My modified temp gauge stays low every time I have the code pop up. Seeing how yours moves up to normal range, should indicate a different problem. If you have a friend with a scanner, invite him over for some beer and be sure the computer is reading a good temp. Check the wire harness real close at the O2 sensor. It would suck to buy a new sensor only to find out it was only a broken/chaffed wire on the harness.

My buddy had a stick take out his O2 harness wire before. Stupid cedar trees......
 

Users who are viewing this thread

Top Bottom