Check Engine Light - OBD-II codes - NO LONGER CONFUSED!
 

2004 F150 SCREW, 4x4, Lariat, 5.4L

The computer threw these codes and my check engine light is on causing the motor to only run on 1/2 the injectors every 32 cycles.

Symptoms:
Engine studders at low RPM's opon acceleration and when going up hills at constant speed (cruise control.) - Feels like torque converter shudder though. Temp gauge on dash works intermittenly. The AC stops working when the temp gauge on the dash stops working - leads me to believe a sensor is workin intermittenly, when it doesn't, it throw a code to the pcm, the pcm goes into safe mode shutting down unneccessary auxiliary components.

This is what the code reader said:
P0119
Engine Coolant Temp
P1289
Manufacturer Control Fuel Air Metering

Now, when I look them up online, P0119 says just what the code reader said, but the P1289 says "Cylinder Head Temperature Sensor Signal Greater Than Self-Test Range."

So I went back to the auto parts store and got a coolant temp sensor, but the guy says theres no such thing as a cylinder head temp sensor. We pull out the haynes manual and boom, there it is, cylinder head temperature sensor replacement. Then I read into it and it involves removing the INTAKE MANIFOLD to R&R it! ... I was like wtf, so I read about changing out the coolant temperature sensor, it says go to the emmisions control section on changing the CHT sensor and follow the steps. WTF!! This leads me to believe that the coolant temperature sensor and the CHT sensor are the same thing... BUT STILL, YOU HAVE TO REMOVE THE INTAKE MANIFOLD TO REPLACE IT.

So, does anyone know if this assumption is correct?? I looked up the parts on a few different web sites and the pictures on all are different - go figure, but I know i shouldn't follow the picture anyway.

Now, I'm pretty pissed that they couldn't put the CTS / CHT sensor in a more accessible location but do I try to go about replacing it myself or take it to the stealership? As you can assume on an '04, I have no more warranty, so I'd get raped there. Although I am a mechaincal engineer and have rebuilt plenty of motors, but all were HEI chevrolets that were in mud trucks, not my daily driver. So it wasn't a big deal if it didn't start up right away. I need this to get to work on monday, you know?
Sorry for the long post, but I just wanted to make sure it was detailed.

How old is your battery ?

I wonder if the wire to the Cylinder Head Temperature Sensor is shorted, broken or not making a good connection.

My Haynes for a 1999 5.4 says to remove the harness and remove the sensor. The 2004 engine does not sound very friendly to work on.

Does the engine runs fine for a few minutes when first started up and then starts to shudder when the coolant heats up?

battery is about 6 months old. I'll have to find the reciept to be sure but definately no older than 8 months.

------------------------------------------------------

no, the motor doesn't run fine and then shudder when the coolant heats up...


basically, the way i see it, when the temp gauge isn't registering anything, thats when what ever sensor is either shorting or not working isn't doing it's job thus putting the pcm into safe mode and stopping all unneccessary auxiliary components (ac and what not.) The gauge working and not working is COMPLETELY RANDOM. I drove all the way home from work today under normal opperation (no noticeable problems, ac working, no shuddering, gauge working) and then when I got off the exit it stopped working = shuddering, no ac. By the time I got to the end of the exit ramp to the light, it was registering the temp again and ac was working....This morning I started the truck and the gauge wasn't working, as soon as i got on the high way the gauge started working and so did the ac, about 1/2 to work, the engine check light started flashing and the motor was misfiring bad, had to pull over on the highway, stop the motor and restart it.

When the temp gauge is registering, the truck will runs fine in normal opperating conditions up until it gets to overdrive. The rpms go up smoothly, it shifts smoothly and then when it gets to overdrive, i don't know if it's the low gear reduction or what but the rpms drop really low (like normal) and it shudders it's way up to about 1900 - 2000 rpms (about 70 mph.)

Now, in safe mode, the manual says to not try to accellerate hard, but even if I try to accelerate moderately, it shudders. This I can assume is due to only 1/2 the injectors working every 32 cycles.

When the gauge isn't working and I go through the system diagnostics ( pressing reset and info on the dash buttons) the first message to pop up is "Engine Data Sensor Error" then goes through the normal "oil pressure ok" "wiper fluid ok" etc BUT if the temp gauge IS working, it says all the normal stuff, Oil pressure ok, engine temp ok, wiper fluid ok...

As far as fuel air mixture sensors - It's basically the MAF and O2 sensor right? are there any others??

It sure sounds like some bad wiring somewhere, UCF, but what are the changes of wires going bad for both the CHT and the ECT sensors at the same time? Have you done any power washing under the hood lately?

If I were going to try to diagnose the problem I think I would get the normal resistance that the ECT and CHT are supposed to be at when the engine is all warmed up and buy a couple of resisters with those values. I would then use those resisters to fake out the computer.

Larry.

nope, no pressure washing under the hood...

The only thing that has changed was my commute. 2 weeks ago I worked 22 miles away and it was stop and go / lights traffic to get to work. Then i went on vacation out of the state for a week, so the truck wasn't driven for 6 days. Got back and drove home from tampa to orlando and it ran like normal.. and then started my new job this weeek. The commute for the new job is 44 miles each way (oddly enough exactly double the mileage) but it's all highway miles so it takes the same amount of time to get to work as my last job did.

haveing 2 sensors / wiring fault at the same time is very unlikely, but when it rains.... it pours (esp in florida)

Diagnostic and discussion
 

Straight from the 2004 PCED:

The 04 5.4L uses only a CHT sensor. ECT values are inferred.

You have an intermittent open circuit either in the CHT sensor or between the sensor and the PCM.

Here is the diagnostic procedure:

Now, chances are, you don't have a scan tool that can read PIDs directly. However, you can still use the HEC or message center to "see" the output of the CHT (via the PCM and the SCP bus). This will enable you to do the tap and wiggle tests to check for intermittents.

Yes, the intake manifold does have to be removed in order to replace the sensor. An ME probably specified its location based on available space and its requisite positioning for correct data acquisition.

If you need the procedure, let me know.

Steve

Steve --- THANKS, that is awesome info.

Now, today on my way to work, i had some more observations. Going down the road to get to the highway is extremely bumpy. From the time i left my driveway until getting onto the highway, the temp gauge worked, as well as my ac. I drove on the highway, which is really smooth for a while and then slowed to through a toll booth. as I slowed, I looked down at my temp gauge and it SLOWLY went down. Normally, when it intermittenly fails, it drops to below "C" like your turning off the truck. As I went through the toll booth, lilke I said, it slowly went down, it went to the 1/4 mark between the 1/2 and the "C" , stayed there for a few minutes and then slowly went down to the "C"... still working, it stayed there for a few minutes, then it dropped like you turn off the truck. That was kinda odd... Now, it stayed off, i got off the hughway, it was still off, I rounded a turn by a light about 1 mile from my office and it worked until I parked it in my parking lot.

On the way home, the temp gauge worked pretty much the whole way home. There were a few times that it shot down below the "c" but a minute or so later it started working again and this was on the highway.

To me, it sounds like the wiring / connection fault might not be it. If it didn't at least stop and start working a few times on the rought county roads, I dont thinks it's due to the wires giggling. I'm thinking sensor failure.

Now, when I got home, I poked around the engine compartment giggling some wires and looking to see where the sensor is. From what I see, It looks like I will be able to take just the air intake tube off and the alternator off and that I would be able to get to the CHT. Now, I'm not sure if I'll be able to get a socket with a swivel or a open end wrench in there and be able to get it to loosen enough, but I can see where it is and that I might be able to get to it.

Steve, no, I don't have the diagnostic equipment but what do you mean by this " However, you can still use the HEC or message center to "see" the output of the CHT (via the PCM and the SCP bus)." ?

You mean, wiggle the wires and check the gauge on the dash??

this may be a stupid question but have you checked to coolant level?

-----

thats a good one, but the coolant is withing acceptable range in the over flow container.


Ok, so heres the update:

I was able to swap out the sensor today with a new one. I unhooked the battery, took think intake tube off, the filter box off, the alternator off, and was able to reach inside the hump of the intake manifold and unplug the sensor. Then was able to get a 3/4 wrench in there to loosen the sensor and then replace it with the new. I giggled the sensor side of the pig tail, the harness side of the pig tail, and I unplugged and replugged the 3 harness connections on the silver metal box on the passenger side firewall. (Is that the PCM?)

Heres what happens now:
When I turn the key on engine off, the sensor works for as long as it's like that. As soon as I start the engine, it works for at least 6-1000 (1-1000, 2-1000, 3-1000, you get the drift) and sometimes up until 10-1000.

So, now I guess it's down to the PCM. Looks Like I'll either be taking it to the stealership or a shop.... ARG, I have been defeated!

You gave it the ole college try. good luck!

Larry

yea, but I hate going to the stealership. Bacause I'm a younger individual they treat me like I'm unversed in anything mechanical. It usually takes a while, and the last time (at that time I was an ME for a Ford QVM certified Body Builder) I had to threat them that I would go to my corportate contacts before they took me seriously. Thats why I try to exhaust every last resort doing it myself. This one really puzzles me though.... ARG! If it was only carbed...... All this new fangled electronic chit...

This one had me curios, I asked a few people about it.
Didn't get much back, just this -

jbrew, info found -

2005 Ford -

Verified Concern, then checked for codes with IDS, Codes P0119 and P1289, Performed Pinpoint test, found faulty CHT sensor, ordered one.

Once the CHT sensor was replaced, it has not had the same problem. I'm hoping this was the last problem... however, one cannot predict the future

__________________________________________________ ____

So you have tried running the vehicle with the new sensor ? Did you go ahead with replacing after testing failed ? Or did you re- install old sensor ?

I hope you installed the new -

Was there any change whatsoever ? Insure a good reboot -

Did you remove PCM fuses, BOTH sides of battery for a period of 20 minutes or longer ?

Did you switch headlights to the on position after battery diconnection?

PCM -

I would have to fully inspect the harness and any/all grounds. Specially around the PCM. O2' s Directly ground to the PCM.

Some things to look at if you haven't caved totally yet . :D

I hate going to the dealership as well, sometimes it's cheaper if you do tho. If you do , tell the service manager to put a sock in it and point out the tech that will be working on your vehicle. You'll most likley net better results if you do.

Good Luck :thumbsup:

Yea, I replaced the sensor, I didn't reuse the old one. But like I said, now when I start it, it works for about 6 - 10 seconds and then doesn't work at all where as it used to be intermitten, now I can tell you exactly when it will go off. But when i have key on engine off it shows the exact temp... CONFUSING!!!!

I took the negative off the batt but haven't taken both off nor have I turned the head lights on, I'm guessing this drains any power left in the PCM? I'm gonna leave them off to more than 20 like you said. When I took the negative off, it was for about 20-30 mins.

As soon as I read your post, i went out to my truck, disconnected both terminals on the battery, and turned the headlights on.

There are 2 grounds, 1 on each side of the PCM on the firewall, I'm not sure if they are O2's or not or if you mean the O2's actually ground to the PCM.

Yea, I most definately will talk to the tech over the service manager, they're always there as a "front" to talk to the customer vs the "greasy tech." Supposedly to make the customer feel more important. Shoot, I'd rather talk to the tech anyday. I'm going to print most of this post (with a little editing to clean my foul language) and explain to him exactly what I've already done and what the reactions the truck has had..

The cool thing, a buddy of mine is going out of town and is letting me borrow his beater yota to commute while I put the truck in the shop (if it comes to that.) I'm gonna see if I can get the dealer to diagnos any other things and try to fix / R&R them myself. Could they flash the PCM and reprogram it?
If worse comes to worse and i need a new PCM what does one cost - $1k ?

I'm thinking also that i might have to replace injectors, O2 sensors, a new Catalytic, or maybe new spark plug module cap things - - what are they called, it's slipping my mind...