hello fellow members this is my 1st post and in need of help i have a 03 navigator 5.4 3v im getting a check engine light code p0117 i changed thermostat and 2 sensors one in back of pass hed and the other one next to the themostat . cooling gauge goes half way and then it just dies auto zone gave me this sensor part number # SU8781 its lite brown with 2 wire clip i been looking and just cant find nothing thx for ur help in advance

 

I'm not sure changing the thermostat will fix your check engine light. The P0117 is the computers way of telling you that the voltage on the ECT (Engine Coolant Temperature) sensor circuit was too low (i.e, less than 0.2V) for normal operation. That would indicate a temp of over 250 degrees F. Did your Navigator overheat at some time?

Sounds like you changed both the CHT (Cylinder Head Temperature) sensor as well as the ECT (Engine Coolant Temperture) sensor.

Could you elaborate on what you mean that it 'just dies'?

Did auto zone say what kind of a sensor it was?

 

AZ
Duralast/Oil Temperature Switch (SU8781) | AutoZone.com

What was the other switch's part number?

Also, did you disconnect the negative battery cable before

Replacing switches/sensors?

 

the needle for the temp goes half ways and just dies goes down and i get check engine light on with the coolant light on and code p0117

 

http://www.autozone.com/autozone/par...631220_0_18589_

 

thats the sensor they gave me and from what i heard from my friend that coolant sensor goes inside the oil pan and from what i been googling the cooling sensor 2 wire harnest gets messt up thx guy for all ur help

 

Are you sure its a 3-valve engine? What is the eighth digit of the VIN?

 

How is the coolant sensor going to sense the coolant temp if the sensor is located in the oil pan

 

Sounds to me then that the PCM is indicating that it is not receiving a valid voltage from the ECT sensor. Normally the PCM sends coolant information over the SCP (Standard Corporate Protocol) network and would be picked up by the HEC (Hybrid Electronic Cluster, aka Instrument Cluster), processor. If the HEC doesn't receive coolant info every so many seconds from the PCM, it doesn't know where to command the temp gauge needle to point.

The Navigator runs three different networks to support communication between the various electronic modules. All three networks are accessable through the DLC. I think your gonna need a scan tool that can read U codes to see if you are having an issue with network communications and/or run a self test on the HEC to see if it is having issues controling the virtual temp gauge.

I'm afraid that this is beyond my pay grade