Help. My temperature gauge is not working. I don't have any trouble codes or warning lights; the gauge is just not working. Stuck in the below cold position. I believe this is causing the engine to idle very high between 1500 rpm and 2000 rpm. I've looked, but cannot find this sensor. Does anyone know where I can find this sensor. I've looked around the thermostat housing by cylinder #5 (top drivers side) but I didn't see it.

Also does anyone think that maybe the throttle position sensor is also the culprit?

Thanks,
Fred

 

Run the HEC Dealer Test to see if there are any cluster-related faults.

Engine temp is sensed by the CHT (Cylinder Head Temp) sensor by the PCM. The PCM sends this data via the SCP network to the HEC. The HEC then takes this data and drives the analog guage.

I wouldn't think the TPS as very likely. Typically, high idle is due to a faulty/sticky IAC valve. However, since you have a failure in either the measurement or the display of the engine temp, more diagnostics are going to be needed, likely with equipment you do not have at your disposal ( a scan tool that can read PIDs). You can try cleaning the IAC valve, but, given the other complicating fault, it may not have any effect.

Steve

 

Thanks for the quick response Steve. I can get a scan tool, but I thought nothing would be displayed unless the MIL light(s) were lit.

The IAC valve is in the plastic intake housing right? I could give that a shot and clean it with some sort of straight alcohol or carb cleaner.

Thanks again,
Fred

09/24/06 update.

I replaced the Idle Air Control valve. Helped a little bit, but I'm still having the high idle. I found the cylinder head temp sensor underneath the alternator by cylinder #5. The part number needed is either Niehoff #TS85221 or Ford OEM F65Z 6G004AB. The problem is some people I've talked to still claim that this sensor doesn't send a signal to the temperature gauge. I also pulled the codes P0125 - Insufficient coolant for closed loop fuel control. P0171 - System too lean (Bank 1). P0174 - System too lean (Bank 2).

I'm assuming that as soon as I solve the P0125 code then the other two codes should disappear.

Any Ideas?

Thanks,
Fred

 

Installed a new cylinder head temp sensor. All codes were cleared and the high idle vanished. The temperature gauge started to work like usual.

Just for good measure, I had the cooling system flushed.

A couple of things to know if you plan on replacing this sensor. 1st it is not the coolant temp sensor. 2nd you will need a 19mm open end wrench.

Keep on posting.

Thanks,
Fred