[KY.BORN]

I'm pretty sure the water pump works because water that kept filling up the port where the sensor goes, I changed it back and forth with the old one a couple of times while I was investigating and water gushed out each time. I'm going to go ver the wiring harness really closely today to see if I catch anything out of the ordinary.
Could another sensor be triggering that code? Like a coolant level sensor or idk something else?
And the fuel is on E because I got home late and didnt want to stop at a gas station that late. Never imagined the car would be sitting this long I guess.

Why is your fuel tank empty...????

 

[KY.BORN]

Why is your fuel tank empty...????

Add a few gallons,,, so it doesn't add to the problem,,Fill your gas can ...

 

[14theroad]

Lol we are a bunch of squirrels...first thing we notice is the fuel gauge. Anyone notice the temp gauge is pegged?

I did a quick search to confirm my suspicions. There are two sensors actually on this vehicle. One for the cylinder head temp that sends its signal to the PCM and a coolant temp sensor. My mustang has the same setup as do most newer cars.

A Cylinder head sensor is typically used for PCM input and controls because it's considered more accurate about real-time engine temps that are critical to timing events and A/F ratios.. I've never seen it used for a dash gauge reading. That's what the Coolant temp sensor is for most likely in this case. .

I dug a little bit more and it turns out the cooling fans are controlled by the ECM which means it's more than likely the Cylinder head temp sensor is what controls the fans.

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The coolant temp sensor is most likely just for the gauge. It's a two wire sensor so it's really easy to test. At room temp it should have a very low resistance. That resistance goes up as the sensor heats up. That increase in resistance is what is translated as an increase in temp on the gauge. So, in theory, if the sensor is bad and pegged the gauge as it is, the sensor will have a very high resistance and not change as the engine warms up.

If you remove the sensor you can test it just like you would a thermostat. Take a volt/ohm meter, Test the sensor at room temp, then drop it in some very hot water or boiling water and watch the Ohm reading on your meter meter, it should go up. If it doesn't budge then you have found a bad sensor.

Another way is if you have access to a handheld OBDII scanner with Live data, you can view the engine PID for the engine coolant temp. The PID will use the Head temp sensor for that reading,so if the guage is pegged but the temp in the handheld says otherwise, you will can investigate the coolant temp sensor and circuit closer.

 

[Josep velder]

Lol we are a bunch of squirrels...first thing we notice is the fuel gauge. Anyone notice the temp gauge is pegged?

I did a quick search to confirm my suspicions. There are two sensors actually on this vehicle. One for the cylinder head temp that sends its signal to the PCM and a coolant temp sensor. My mustang has the same setup as do most newer cars.

A Cylinder head sensor is typically used for PCM input and controls because it's considered more accurate about real-time engine temps that are critical to timing events and A/F ratios.. I've never seen it used for a dash gauge reading. That's what the Coolant temp sensor is for most likely in this case. .

I dug a little bit more and it turns out the cooling fans are controlled by the ECM which means it's more than likely the Cylinder head temp sensor is what controls the fans.

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Welcome to the BBB Industries, Inc. Technical Service Bulletin and Wiring Diagram tool. This page is currently restricted to registered members. If you would like to become a member, please click here to register for an account. If you have an account already and are...

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The coolant temp sensor is most likely just for the gauge. It's a two wire sensor so it's really easy to test. At room temp it should have a very low resistance. That resistance goes up as the sensor heats up. That increase in resistance is what is translated as an increase in temp on the gauge. So, in theory, if the sensor is bad and pegged the gauge as it is, the sensor will have a very high resistance and not change as the engine warms up.

If you remove the sensor you can test it just like you would a thermostat. Take a volt/ohm meter, Test the sensor at room temp, then drop it in some very hot water or boiling water and watch the Ohm reading on your meter meter, it should go up. If it doesn't budge then you have found a bad sensor.

Another way is if you have access to a handheld OBDII scanner with Live data, you can view the engine PID for the engine coolant temp. The PID will use the Head temp sensor for that reading,so if the guage is pegged but the temp in the handheld says otherwise, you will can investigate the coolant temp sensor and circuit closer.

Its a brand new sensor straight from the dealer. How can I check the wiring to see if theres a bad spot in it?

 

[KY.BORN]

Lol we are a bunch of squirrels...first thing we notice is the fuel gauge. Anyone notice the temp gauge is pegged?

I did a quick search to confirm my suspicions. There are two sensors actually on this vehicle. One for the cylinder head temp that sends its signal to the PCM and a coolant temp sensor. My mustang has the same setup as do most newer cars.

A Cylinder head sensor is typically used for PCM input and controls because it's considered more accurate about real-time engine temps that are critical to timing events and A/F ratios.. I've never seen it used for a dash gauge reading. That's what the Coolant temp sensor is for most likely in this case. .

I dug a little bit more and it turns out the cooling fans are controlled by the ECM which means it's more than likely the Cylinder head temp sensor is what controls the fans.

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Welcome to the BBB Industries, Inc. Technical Service Bulletin and Wiring Diagram tool. This page is currently restricted to registered members. If you would like to become a member, please click here to register for an account. If you have an account already and are...

www.bbbind.com

The coolant temp sensor is most likely just for the gauge. It's a two wire sensor so it's really easy to test. At room temp it should have a very low resistance. That resistance goes up as the sensor heats up. That increase in resistance is what is translated as an increase in temp on the gauge. So, in theory, if the sensor is bad and pegged the gauge as it is, the sensor will have a very high resistance and not change as the engine warms up.

If you remove the sensor you can test it just like you would a thermostat. Take a volt/ohm meter, Test the sensor at room temp, then drop it in some very hot water or boiling water and watch the Ohm reading on your meter meter, it should go up. If it doesn't budge then you have found a bad sensor.

Another way is if you have access to a handheld OBDII scanner with Live data, you can view the engine PID for the engine coolant temp. The PID will use the Head temp sensor for that reading,so if the guage is pegged but the temp in the handheld says otherwise, you will can investigate the coolant temp sensor and circuit closer.

AH, Us squirrels already new of the temp. gauge being pinned..Thats his problem, just you shouldnt let the tank get down that low period...can lead to other problems...why open another can of worms...

 

[14theroad]

To be clear, which sensor did you replace? You mention a coolant temp sensor in one instance (aka ECT) then mention a HTC (should be CHT) sensor in later on. Engine Coolant temp and Coolant Head Temp sensor are not the same.

The ECT is located on the engine near the high pressure fuel pump on the drivers side of the engine.
The CHT is located on top of the motor /valve cover area or on the backside of the head.under the valve cover area.

If you go to Rock Auto you can see the physical difference between them. The CHT is much longer and narrower than the ECT.

Found this in my search. Interesting, it's counter to how I'm familiar with these sensors working on most cars but this guy is a ex Ford master tech so it's worth checking out. It's a 2.5L non turbo motor but false overheat issue is identical to what you are experiencing.

 

[KY.BORN]

Nice find...But how is water getting to the top of the engine to corrode the sensor connector??

 

[centex]

More just FYI, limited excerpts from the WSM ….

"A strategy called Fail Safe Cooling is built into the PCM that will control the engine if it starts to overheat.

Fail Safe Cooling has two modes: A ‘Closed Loop’ mode that relies on CHT sensor and an ‘Open Loop’ mode that relies on ECT sensor. When the engine starts to overheat, the decision to go into closed loop or open loop mode is made based on sensor availability and sensor failures. Closed loop mode takes priority over open loop. The reason is that a good CHT sensor is able to reliably track engine block temperature at all times, while the ECT sensor will fail to do so when the engine coolant is dumped."

…..

"Closed Loop Mode

Stage 1 of the strategy commences if the engine starts to overheat. The CHT sensor transmits a signal to the PCM , which moves the temperature gauge pointer into the red zone.

If the engine is not switched off and the temperature continues to rise, the Powertrain Check Lamp is illuminated. This indicates to the driver that the engine is approaching critical limits and should be stopped. At this point DTC P1285 is set in the PCM which can be retrieved using a scan tool."

…...

"Open Loop Mode

This mode is entered when the ECT sensor indicates a high engine temperature that is rising at a dangerously high rate, much faster than expected based on current engine running conditions. This mode can also be entered when all sensors used in Fail Safe Cooling determination are failed.

When this mode is activated, the PCM will restrict load, and restrict engine speed to below 3000 RPM, then start ramping engine speed down slowly to as low as 800 RPM and hold the speed there.

At the same time, the PCM will also move the temperature gauge pointer into the red zone and the P1285 code is set."

>>>

So, among other things, we see that the PCM may move the dash temp gauge based on input from either the ECT or CHT sensors.

>>

Heaven forbid, given the free availability of youtube, that anyone hell-bent on DIY problem solving would spend $25 to access the extensive 1.6 engine cooling diagnostic and testing section 303-03A in the WSM, which covers many more aspects of the system than have been broached here (ever think there might be an issue with the solenoid-controlled coolant bypass system, among the many other things potentially pertinent to the symptoms reported?)

..... following with popcorn in hand ..... it's at least as good as a 3-stooges replay .....

 

[Josep velder]

To be clear, which sensor did you replace? You mention a coolant temp sensor in one instance (aka ECT) then mention a HTC (should be CHT) sensor in later on. Engine Coolant temp and Coolant Head Temp sensor are not the same.

The ECT is located on the engine near the high pressure fuel pump on the drivers side of the engine.
The CHT is located on top of the motor /valve cover area or on the backside of the head.under the valve cover area.

If you go to Rock Auto you can see the physical difference between them. The CHT is much longer and narrower than the ECT.

Found this in my search. Interesting, it's counter to how I'm familiar with these sensors working on most cars but this guy is a ex Ford master tech so it's worth checking out. It's a 2.5L non turbo motor but false overheat issue is identical to what you are experiencing.

Awesome, I didnt know there were two sensors, I changed out the one on the side that pops in with an o-ring and a retainer clip. Going to look for the other one.
Thank you ?

 

[Josep velder]

I didnt see a spot for another temp sensor on top of the engine by the coils. The one circled in red is the new one I installed.

 

[KY.BORN]

I didnt see a spot for another temp sensor on top of the engine by the coils. The one circled in red is the new one I installed.

Was reading the CHT sensor will throw it into that mode with a P1299 code.. Will limit the engine running RPM'S down to 800.....I'm trying to locate it on mine but cant find it either..Mine is a 2.0....Not on top in between plugs.....Breaking News.....Just discovered it on my 2.0 ..Saw a top view of an open head..Its in the back , fire wall side.. Have to remove the wiper cowl and air intake to see it, around the 1st and 2nd spark plug but angled down and back,,its hidden well..Dont know about your 1.6 location , hope better than that bugger,,,,,,,,..One of the stooges...

 

[Josep velder]

Was reading the CHT sensor will throw it into that mode with a P1299 code.. Will limit the engine running RPM'S down to 800.....I'm trying to locate it on mine but cant find it either..Mine is a 2.0....Not on top in between plugs.....Breaking News.....Just discovered it on my 2.0 ..Saw a top view of an open head..Its in the back , fire wall side.. Have to remove the wiper cowl and air intake to see it, around the 1st and 2nd spark plug but angled down and back,,its hidden well..Dont know about your 1.6 location , hope better than that bugger,,,,,,,,..One of the stooges...

I found this yesterday, it seems that the recall "fix" to the overheating issues the 1.6 had was adding a coolant level sensor. Its behind the passenger side headlight. It will also throw a p1299 code and kick it into high temp mode if it fails.
Freaking thing cost $640 online ??‍♂

 

[KY.BORN]

I found this yesterday, it seems that the recall "fix" to the overheating issues the 1.6 had was adding a coolant level sensor. Its behind the passenger side headlight. It will also throw a p1299 code and kick it into high temp mode if it fails.
Freaking thing cost $640 online ??‍♂

If a recall, shouldnt you qualify if it wasn't performed before??

 

[Josep velder]

If a recall, shouldnt you qualify if it wasn't performed before??

Mine was done, that's how I have the $640 coolant level sensor on my car. The tube is full if gunk, I'm going to soak it a while and clean it out to see if it fixes it I guess.

 

[KY.BORN]

Mine was done, that's how I have the $640 coolant level sensor on my car. The tube is full if gunk, I'm going to soak it a while and clean it out to see if it fixes it I guess.

Hard to believe $640 coolant sensor..you sure , not a typo error....???

 

[Josep velder]

Hard to believe $640 coolant sensor..you sure , not a typo error....???

Cheapest one I found was $629

 

[KY.BORN]

Cheapest one I found was $629

Thats some crazy *** design...Were you able to clean it out?? Looks like it comes right off the overflow tank..Did you Google the part number just to see if any are made in after market??

 

[Josep velder]

I cleaned it but been working all weekend so haven been home to install it, I looked all over for an alternative, they're very rare, haven't tried the junkyards yet, hoping mine still works, wish I knew how to test it.

 

[Josep velder]

I cleaned it, hooked the hoses back up to it, left it unplugged, connected the obd reader to the car, erased the codes, plugged the sensor back in, turned the car on, in two seconds it went back into p1299 mode. read the obd codes and they're back.
The sensor has no moving parts and it wasnt an issue before I changed out the temp sensor.
I'm really thinking I fried the computer when i used the jumper wire on the coolant sensor pigtail. That's when it went into P1299

 

[Josep velder]

I just spoke with a junkyard that sells alot of escape body parts on Ebay and the guy said he gets a ton of calls for the coolant level sensor. Said it's a bad part and they wont sell them. Tells people to get it from the dealer ??‍♂