P0128 - Powertrain

[WY-Dave]

Second time getting this, 1st time went away after about 10 starts

Back again and so far not resetting

From online "Error code P0128 indicates that your engine coolant temperature is below the thermostat regulating temperature. This means that your Engine Control Module (ECM) or Powertrain Control Module (PCM) has recognized that your engine is running cooler than it's supposed to."

Stays on even after a warmup, stop and restart
Can't find anywhere to reset/clear in AlphaOBD, ODBLink or Torque Pro

 

[mtofell]

I had a similar code (maybe even the same on) on my 6.4 Hemi a few years back and it needed a new thermostat. IIRC, mine said something about not reaching operating temperature in a normal amount of time.

 

[2003F350]

Judging from the code and the picture you sent, you are WELL below the operating temperature the computer wants to see - it probably wants to see 180+ since you're a diesel. If you're not getting there, your thermostat is likely stuck open and needs to be replaced. OR it's been really cold and you aren't letting it warm up at least a little bit before you go out driving. When it's less than 30 degrees out I let mine idle for at least 5 minutes before I head out to scrape it off, it'll have been sitting at high idle for at least 3 of them, plus the 3-5 minutes it takes to clear it off, and away I go.

 

[62Blazer]

As already mentioned, I would suspect the thermostat is stuck open and basically allowing over-cooling of the system. In normal conditions the thermostat would close/partially close and restrict how much cooling it has. Guessing the factory thermostat is probably closer to 200F rated? The fact that both the trans and oil temps are also low makes me think thermostat also. If the coolant temp sensor was giving a bad signal it wouldn't cause the engine oil and trans to read cool also.
The picture also shows it's not that cold outside (41F) either.

 

[WY-Dave]

this morning the ruck went nutso when I started it, ding ding ding service brake system I think (flashed so fast) pulled it out of the way of the garage so not to block it if the truck became immobile. Stopped it, used Torque Pro to snoop the codes and did a reset and not going to say it (shh so it don't hear us) but it all clear up and the check engine light went out




Code U0121 stands for Lost Communication with Anti-lock Brake System Module. Anti-lock brakes are required on all modern vehicles.
U0212 is defined as a Lost Communication With Steering Column Control Module.
U0415 indicates “Invalid Data Received From Anti-Lock Brake System (ABS) Control.” For The Car Owner.
U11B9 The Diagnostic Trouble Code (DTC) sets when the Bus messages not received from the Radio Frequency (RF) Hub Module for approximately two to five seconds
U1412 Set when the PCM gets an implausible signal over the CAN-C circuit from the ABS Module

 

[2003F350]

As already mentioned, I would suspect the thermostat is stuck open and basically allowing over-cooling of the system. In normal conditions the thermostat would close/partially close and restrict how much cooling it has. Guessing the factory thermostat is probably closer to 200F rated? The fact that both the trans and oil temps are also low makes me think thermostat also. If the coolant temp sensor was giving a bad signal it wouldn't cause the engine oil and trans to read cool also.
The picture also shows it's not that cold outside (41F) either.

If it were a gasser yes he'd be closer to 200, but he's got a 6.7, and mine keeps a pretty steady 190 within a couple degrees plus or minus.

 

[62Blazer]

this morning the ruck went nutso when I started it, ding ding ding service brake system I think (flashed so fast) pulled it out of the way of the garage so not to block it if the truck became immobile. Stopped it, used Torque Pro to snoop the codes and did a reset and not going to say it (shh so it don't hear us) but it all clear up and the check engine light went out

View attachment 538416


Code U0121 stands for Lost Communication with Anti-lock Brake System Module. Anti-lock brakes are required on all modern vehicles.
U0212 is defined as a Lost Communication With Steering Column Control Module.
U0415 indicates “Invalid Data Received From Anti-Lock Brake System (ABS) Control.” For The Car Owner.
U11B9 The Diagnostic Trouble Code (DTC) sets when the Bus messages not received from the Radio Frequency (RF) Hub Module for approximately two to five seconds
U1412 Set when the PCM gets an implausible signal over the CAN-C circuit from the ABS Module

With that variety of different random codes, and a lot of "loss communication" to various systems, my first suspicion would be a low battery. When you started it, and assuming it's cold outside, it took everything the battery had left to start the vehicle which caused a momentary low voltage condition until the alternator could take over. Modern vehicles can act real goofy with low voltages.