Hi all,

I have a 2003 Ford Ranger, recently I had the heater core fail. One thing that happened during the heater core starting to leak is the "THEFT" light came on brighter than normal and no longer flashes when the truck is off. Also when the theft light started acting up the O/D OFF light came on and would not shut off. If I pushed the O/D off button the Theft light will go out and then come back on after the button is released.

After the heater core was replaced the lights stayed on as described above. Every once in a while the O/D off light would stay off but then come on later. No really problem besides the lights and O/D off button not working. Now today the O/D off light started flashing and the truck kept shifting in and out of O/D.

I'm leaning towards a speed sensor issue but open for any suggestions. I'm going to check and see if there is any codes tonight and will post my results. One other thing that happen with the heater core leaking is the "CHECK ENGINE" light came on because the O2 sensor was shorted out. Have the O2 sensor now and plan on replacing it while I trouble shoot the erratic shifting in and out of O/D.

Any help or ideas would be greatly appreciated. Thanks in advance.

 

If the speed sensor on an '03 is on top of the rear axle, its easy to change and fairly cheap.

When mine went out on my 2000, the CEL came on, OD light flashed and the truck wouldn't shift unless you nearly red lined it, or if you shifted it manually through the gears and then the shifts were really harsh.

Was the dash fully removed to do the heater core? Maybe a pinched wire or loose connection in the dash? I haven't had to battle that project.

 

Yes removed dash to replace the heater core. The issues with the lights never changed with the heater core replacement. I was pretty careful with the wiring so I don't think its a pinched wire, but I will look.

The issues with the shifting in and out of O/D just started today along with the O/D off light flashing and I replaced the heater core a month ago. I do believe it is electrical or speed sensor because if your driving at interstate speeds and hit a bump it felt like the cruise would go off and back on. That is one reason I was thinking speed sensor.

 

Pull codes to see what the computer has to say.

 

The O/D button it not connected to the theft light except in that they may share a ground. Should that ground be 'missing', as in loose, corroded, or an unseated connector, one light may use the other as its ground, being closer, electrically, to ground than the 'normal' ground. I would check that wires are good, connections are tight, and grounds un-corroded.
The shifting in and out of O/D would be more likely un-related to the heater core replacement. I'd check the VSS, and if you have cruise, check that it works or doesn't. I had a VSS fail, and cruise didn't work, and the transmission shifted in and out of O/D, and I think the torque converter was left 'unlocked' until I replaced it.
tom

 

Welcome to FTE.
Good idea to scan for trouble code clues, but most code readers, or low end scan tools will only have access to the engine computer/controller, so to also query the tranny computer/controller for clues, you'll need a high end scan tool that's able to access it. If you don't have, or can't come by one, consider investing in a low cost ELM scan tool running FORScan or the like software on the viewing device of your choice, as that combo can access All of the vehicle computer/controllers, then post up All set, or pending code number clues found.

If the rear ABS speed sensor is the problem, you may also be having problems with the ABS, cruise control, speed-o & tranny shifting, as all those systems also use the rear ABS speed sensors PID output to do their thing & the ELM can access those systems controllers.

More thoughts for consideration, let us know what you find.

 

Thanks for the welcome, enjoying the information packed forums.
I pulled the code and nothing related to the transmission or speed pickup. Code was P2196 - O2 Sensor Signal Stuck Rich Bank 1 Sensor 1.

pawpaw, definitely interested in a better reader. Any recommendations? The reader I have now is a Innova 3100a.

No ABS issues, cruise works but seems to cut in and out like you would hit the coast button but then comes back and controls speed as it should. The transmission shifts normally except when the O/D OFF light starts flashing and then it shifts in and out of O/D. If you press the "O/D OFF" button the THEFT light goes from being dimly lit to brighter. The Theft light does this all the time doesn't matter if your driving down the road, sitting still, even if the truck is off.


tomw, Would you be able to tell me where the ground, and connector may be located?

I agree it seems very odd to me that the O/D OFF button is effecting the brightness of the theft light. When the heater core failed it failed slowly and soaked the insulation under the rubber floor mat.

Recommendations for checking the VSS? Cruise works but cuts in and out with hard bumps in the road. There is a certain bump it cuts out on every time I drive over it.

I would agree that the torque converter locks and unlocks with the flashing of the O/D OFF light. Engine RPMs change.

Will be looking for the ground and checking its connection and for corrosion. Also will be checking VSS connections and any connections leading to the VSS. If no smoking guns found thinking of changing the VSS to see if and how things react.

Any ideas or recommendations will be appreciated. Thanks.

 

Here is a thread I started 3 years ago about the ELM scan tool & FORScan freeware that's tweaked for Fords. https://www.ford-trucks.com/forums/1...-scantool.html
The ELM is way more sophisticated than my Actron CP9145, or your Innova 3100a.
I don't believe the Amazon LYL vendor I bought mine from is selling the ELM anymore, but vendor BAFX I believe is still selling a Bluetooth ELM if your interested in that form of coupling.
WiFi can transfer data at a higher rate & longer diatance as I understand, but if data rate & distance isn't a concern, then a Bluetooth model would likely be fine for a wireless connection.
Visit the FORScan site to see what the latest version has to offer, as the software is constantly being up dated.
Seeing as how the OD light has been blinking, the tranny controller has likely stored a trouble code/s & the ELM running FORScan can query the tranny controller for clues.

 

Pawpaw, unless things have changed, I believe that the transmission codes are not stored.
I would bet a donut they for sure were not stored in 2003 MY transmission controllers.

Therefor, if you get a blinking OD light, it behooves to get the code retrieved before the ignition switch is turned to OFF.
tom

 

I guarantee that you're wrong. Transmission codes have always been stored. They stay in memory for about a month after the last time the light flashed, unless there is a problem with the power to the KAM (Keep Alive Memory) feed to the PCM.

 

You need to run down the cause of the P2196 O2 sensor signal stuck rich code & put that right.

 

O2 sensor I have and will be replacing Saturday. I will update thread after that is done and code is clear.

 

O2 sensor isn't likely the root cause of the problem, maybe a fuel injector with a runny nose is, or maybe you have a fuel pressure problem, or a spark plug misfiring?
In any case the O2 sensor is just reporting what it's seeing & what it's seeing is too much fuel in the exhaust, so that suggests an up stream problem, maybe not a problem with the O2 sensor.
Since we seem to be talking about one O2 sensor, does it follow that we're talking about a 4cyl engine?

 

Only reason I'm wanting to change the O2 sensor is that when the heater core let go it flooded the sensor with antifreeze/water. I just want to make sure that I have a working O2 sensor before I go any further. Also ordered a elm327 adapter so I can see a little more information while trouble shooting things.

 

Ok, that sounds reasonable as coolant can take out the O2 sensor.
If it's been driven for a length of time with the fuel trim corrupt rich, it can cause the cat converter to over heat from having to process the excess fuel in the exhaust & that can cause the converter matrix to melt & raise exhaust back pressure & mess with how the engine runs & is cooled, all a vicious circle.
So when you get the ELM & load FORScan, have it take a look at fuel trim, along with the O2 sensor switching range & speed & let us know what you find.