No AC!

[TNHellion]

I just picked up a 2000 explorer and all was good until the A/C cut out and check engine light came on. I'm not much of a mechanic, so please dumb it down for me. I had the auto place check codes and it came back with

P0118 engine coolant temperature sensor circuit high input
1 open of sort circuit
2 electrical connection
3 faulty ect sensor

P1117engine coolant temperature sensor circuit intermittent condition
1 poor electrical connection
2 failed ect sensor

(They couldn't find a Ford code for the last one, so the printout is for a volkswagon
p1118 sensor heat circuit open bank 1 sensor 2
1 failed heated oxygen sensor bank 1 sensor 2

*edit
Found the ford p1118 code on the forum

P1118 Manifold Absolute Temperature Circuit Low Input

Like I said, I'm new to fixing my vehicles and can replace anything that I know needs to be replaced, its getting to that point that I'm usually stuck on. Should I just replace the ect sensor? The truck seems to be running fine aside from not having any A/C

 

[drdoom]

I would test them first... Might be the wiring. Get a shop manual it tells you how to do the tests.

 

[TNHellion]

I would test them first... Might be the wiring. Get a shop manual it tells you how to do the tests.

Thanks drdoom. I have a Haynes manual that I'm looking up now to check how to test it but its a little confusing. It says to disconnect the sensor and use a ohmmeter to check the resistance, I guess I unplug the connection and test the sensor while its still installed? It seems to be a pain to disconnect lol

thanks for the help!

 

[JimMadsen]

First, make sure you know how to use the ohmmeter: http://www.ehow.com/how_2282412_use-ohmmeter.html

Then onto testing:

http://www.carrepairpro.com/2012/02/how-to-test-engine-coolant-temperature.html


How to test Engine coolant temperature sensor?
Engine coolant temperature sensor is also called as ECT.

The details to test CT sensor is a follows :---


TESTING


There are a few items you should check before beginning more extensive testing.


Check for poor connection at the PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections.
Look for a damaged harness or damaged wiring going to the ECT sensor, especially if heavy work has recently been done where the connector could have been damaged.

Sensor Installed in Vehicle


Click image to see an enlarged view (image/chart is at the link above)
Fig. ECT sensor resistance value chart

Disconnect the engine wiring harness from the ECT sensor.
Connect an ohmmeter between the ECT sensor terminals.
With the engine cold and the ignition switch in the OFF position, measure and note the ECT sensor resistance.
Connect the engine wiring harness to the sensor.
Start the engine and allow the engine to reach normal operating temperature.
Once the engine has reached normal operating temperature, turn the engine OFF .
Once again, disconnect the engine wiring harness from the ECT sensor.
Measure and note the ECT sensor resistance with the engine hot.
Compare the cold and hot ECT sensor resistance measurements with the accompanying chart.
If readings do not approximate those in the chart, the sensor may be faulty.

Sensor Removed from Vehicle

Remove the ECT sensor from the vehicle.
Immerse the tip of the sensor in a container of water.

 

[TNHellion]

Update (in case anyone on the information superhighway has the same problem) I tried to test the sensor but it's a PITA to reach and couldn't get a reading. I was going to hit up the junkyard and try to get a connector to make it a lot easier, just connect it to the spare and use the wires to test.

In the meantime more problems came up! Truck wont start after it gets warmed up. It will start fine to go to the store but after it heats up i'll be walking home! If im lucky I can get it to run by holding down the gas and having it sputter and run like crap. Once it cools down it will start okay again. I read on the interwebs that this can also be related to a bad ect. no trip to the junkyard for me. battery guage is also showing low but battery is fine, seems like no gas but there is plenty and fuel pump is turning on.

I picked up the sensor at the auto place for $15, but again its a PITA to reach. I'll let ya know how many curse words it takes to change and if it helps any. Ordered an OBDII sensor online that should show the coolant temp, hopefully it'll be fixed before it gets here but still excited to play around with it when I get it.

 

[bobflood]

Would help to know which engine you have. I assume that your temp guage is still working, as you did not mention that it wasn't. The temp sensor for engine management and the sender for the temp gauge are right next to each other in the thermostat housing. IIRC, the gauge sender has one wire; the ECT sensor two wires. Very likely your problem WRT starting, engine is hot but computer thinks it's cold and dumps in too much fuel. Good luck.

 

[TNHellion]

Would help to know which engine you have. I assume that your temp guage is still working, as you did not mention that it wasn't. The temp sensor for engine management and the sender for the temp gauge are right next to each other in the thermostat housing. IIRC, the gauge sender has one wire; the ECT sensor two wires. Very likely your problem WRT starting, engine is hot but computer thinks it's cold and dumps in too much fuel. Good luck.

Thanks bob! I think so too, but I'm no mechanic, it just makes sense. Though I've heard it could be the starter or the fuel pump (fuel pump is turning on fine) from a couple guys who haven't looked at it but say it wouldn't be the sensor. Anyway, it's a 4.0 SOHC. The connector on the ect is grey (and has two wires), I think the sender next to it is brownish orangish.

Anyway, I work 12 hour shifts 5/6 days a week so haven't had time to just get right into it but tonight I got a start. Sorry if I'm off a bit ( don't know all the proper part names), but Removed the hose that was connected to the MAF sensor, and the throttle body as well as a cable going to the alternator to make some room to attack the ect, tomorrow I plan on draining the coolant so I can take off the thermostat housing and that should give me enough room I hope. Any suggestions always appreciated! I got a new ect sensor so I guess I'll test the old vs new to make sure its not working, if its working I guess I can assume the wiring is bad.

yes, temp gauge seems to work fine, stays in the middle and it hasn't overheated or anything.

 

[TNHellion]

Took off the thermostat housing and had plenty of room to take out the ect, only stabbed myself once trying to get the hose off the thermo housing. Old sensor is useless, new sensor is fun to play with! Gotta throw the new one in tomorrow after work and hopefully alleviate a few problems, assuming everything goes back together lol

 

[TNHellion]

Well, I have AC! The truck is like the arctic. The ect sensor went in nice and easy. The upper thermostat housing was a little brittle/chewed on where it fits into the lower and it was spitting out coolant after everything was put back together. Also managed to strip one of the bolts on the housing, it took out the jacket the bolt screws into. Cleaned the housing and slapped some gasket sealer before tightening back up and it seems to be holding for now. Truck starts with no problems, ac is cold and I might even take it for a spin to the auto place to have 'em check things out.

Next step ... new upper thermostat housing and try to put the bolt threw to hold it on. The stripped bolt is in the back. Assuming I can put a bolt all the way through it looks like another pain, but maybe not as big a pain as replacing the entire housing.