Hello all, I have an '04 F350 6.0 and the temp gauge is intermittent. I have an Edge CTS monitor that shows temps for the coolant and oil temps still. So my question is, does anyone know how the wiring is routed to feed to the guage cluster from the temp guage. I assume the feed goes from the guage to the PCM and then to the guage cluster ( and the FICM ). I don't know where to look. The guage fails and then my fan comes on full and a/c stops working, I assume it's a failsafe to keep the motor cool. I am thinking of replacing some of the wiring harnessed. I found the harness going down th frame rail just by the PCM to have rubbed through making my reverse lights come on all the time and my truck stall. There were two wires in there that were shorting. I know there are issues with chaffing. Any help would be appreciated :-) Still trying to solve the mystery. Thank you in advance for any ideas.

 

All sensors are read by pcm. The pcm then outputs a signal to control dash. It sounds like your ect sensor or wiring is suspect. PCM infers a value, if the input isn't working, thus there is always a value so the computations by the PCM can be done, and thus it provides a value when requested by the odb monitor.

 

Hi, thank you for the information, so if I am getting this right, the CTS monitor is getting a value, not necessarily a real value from the PCM because it will essentially generate one if there is a failure right ? Therefore as you said, my sensor may be malfunctioning or the wiring may be at fault. I'll need to see how to test that sensor to see if it's the culprit. As I understand it, it should be a 5volt signal or less depending on what it's reading, so when it's cold it should either be +5 or 0 volts, not sure which is correct cold and then it'll ramp as the temperature changes, sound about right ? Again thanks for taking the time to respond.

 

Moved to 6.0L PSD forum.

 

I normaly do not respond much on tuner or aftermarket monitors because I have no hands on experience with them.
However I read every post about them trying to learn.
One thing I have noticed on the 6.0 all seem to have trouble reading the generic codes/values and work better with the Ford specific values. Altho some have troubles entering some of the pid values to change to spectfic.
Rusty AxleRod and Money pit have both posted extensive list of values available for Scan Gauge II and Tourque pro.
Other wise it appears to be trial and error to determin which works best. That and a few calls direct to the product developer.

 

Not sure this is an issue with the setup of the PID. The pcm (computer) has inputs from all the engine's sensors. We use the odb2 port to ask the pcm, "what is the value of something" and the computer gives back a value.
For some sensors, the pcm "has" to have a value in order to decide how to do something, for example how much fuel to deliver. The ford programmers ecide what 'default' value is safe to use if it can't get a real value to be able to make reasonable judgements for calculations.
For example, use the coolant temp in place of oil temp when necessary.
In the next 6.7, there are a lot more sensor inputs. In the first few years, in real cold places, the 6.7 had issues. Turns out, nobody thought the temps could go below -40 so they didn't have sensor data at that cold temp and lots up angry owners until sw changes and new sensors came out.
All this from other threads here on fte.

 

As I understand it the monitors and apps use some differnt values to interpret what the PCM is saying. My scanner reads directly from the pcm and I have noticed some times the monitors and phone apps do not always agree with what my scanner shows.
I may be wrong on this like I said no first hand experience with this cause I dont do tuners, monitors or phone apps. Just scan tools Computer based or hand held.