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SVT P0125 code

18K views 16 replies 11 participants last post by  amc49 
#1 ·
Check engine light is on, code P0125-(Insufficient Coolant Temperature for Closed Loop fuel control). Not really sure what it means, have heard it could be just a sensor or that the thermostat could be stuck open. Any suggestions?

04 SVT, Black, 5door
(no mods)
 
#3 ·
Low coolant level, faulty coolant temperature sensor or stuck open thermostat are the likely causes.

The code is telling you that the ECU can't operate the fuel system in a closed loop fashion - where the air fuel ratio is "tweaked" for optimum efficiency using inputs from various engine sensors - because the engine is taking too long or never reaching its normal operating temperature, a prerequisite to entering closed loop functionality. Consequently, it's may be running rich all the time in an attempt to "warm up".
 
#7 ·
ok, well because of limited money and freakish snow in dallas i have not fix anything. I bought a new therm and looked at the old one, looked like it wasnt stuck in the open position, it was closed when i took it out. so thinking about buying and replacing sensor...idk
 
#11 ·
Has anyone else had this problem too? My 04 SVT just started throwing this code. Before this code I had the code for spark plug misfire in bank #1. Replaced plugs and wires. A week later, the p0125 code and engine light popped on. thermostat or temp sensor? or?????
 
#12 ·
This code means your car hasn't reached 180* or so in a specified time. It means your thermostat is stuck open 99% of the time. You could also have some resistance in the ECT sensor or wiring. More temp = less resistance with thermistors so more resistance would make the PCM think it was a lower temperature.

The sensors measure poorly in air as well so a low coolant level may cause an air bubble to form near the sensor...but these aren't difficult motors to "burp".

I only have luck with Ford thermostats. I've had two Autozone stats stick open on me. I find the oil temp runs cooler than the coolant temp when this happens. Unless I really rev the motor the oil temp always was a little lower on the gauge.
 
#13 ·
I just want to make sure I understand the system here. My 2003 SVT is giving me the P0125 code too. It is not running what I would call cold at just below the halfway point on the temp gauge. The thing I want to make sure of is that the sensor for the computer is the same as the one for the gauge. It appears the one on the thermostat housing is for the fan. I disconnected the sensor and the gauge did not change. I appreciate any help I can get with this. The car seems to run fine but that yellow light is something I can not deal with!
 
#14 ·
I no longer have a check engine light! I had the low coolant temp code (P0125) for the last month or so. I tried three different thermostats. The last one had the water temp gauge running just below half way and that was not good enough for the computer. As a last resort I bought a Ford thermostat from the dealer and the problem is gone. The aftermarket thermostas were rated at 195 F. They were Stant and Duralast. The Ford unit has 92 C stamped on it, which is just under 198 F. My suggestion to anyone changing a thermostat is to spend the extra money on the Ford one. It was $16 versus $8.
 
#15 ·
Light came back on

For 7 months after I changed to the Ford thermostat the light and P0125 code did not appear. It came on and the temp indication did seem lower than normal. I changed the coolant temp sensor and now everything is the way I remember it being and the temp levels are consistant. In my case the coolant sensor was the probably the issue all along.
 
#16 ·
P0125

I just got the P0125 code and i just replaced the ECT Sensor. About to change the thermostat and flush it really well and for the first time since i've bought it am going to put the dealer recommended GOLD Coolant from Ford and see what that does. Has anybody considered the coolant being the problem?
 
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