I have a 2002 ford f150 4x4. Recently my engine would rev up while driving in overdrive. After doing this for a while, the check engine light came on and I was told it was a defective TPS. I replaced the TPS and the truck drove fine for about a month. Then it started doing the same thing again. Thinking that autozone gave me a faulty TPS I replaced it again. This changed nothing. The trouble codes that come up are P1125, P0122, and P1121. I was told my connector could be bad so I cut the connector off and soldered the wires directly to the sensor. This also changed nothing. I don't know what else to do.

 

Here is a list of the codes. Makes me wonder if there is not something wrong with the MAF. I'm assuming you have a 5.4?
http://www.svtlightnings.com/scantoo...tc%20codes.htm

 

Did you re-boot. I would with that. Clear the KAM completely and let go thru it adaptive strategy default.

Not saying that will fix it, but the PCM/Comps do get buggy sometimes. A fresh re-boot is worth a shot, since it costs nothing.

 

Goos point, jbrew.

 

Check the PCV system especially the rubber hose that comes out of the intake. The PCM is basically telling you that the engine is getting air it can't account for. Also check the intake system from the air box to the throttle body for any leaks. Hopefully you don't have an after market CAI.

 

I was thinking that also. I took the MAF sensor off and cleaned it with eletrical contact cleaner. The little wires in the sensor were very dirty looking at first, but after cleaning they are shiny. This didn't change anything either and I didn't know if I should replace the sensor since it is over a $100 part. It is a 5.4L V8

 

Jbrew,
I have cleared the trouble codes and after a few minutes of driving they will all return again. I don't know much so are you talking about doing something else when you say clearing the KAM?

 

Yea, you always have to disconnect the battery for 20 minutes or so. That clears the KeepAliveMemory (KAM) , specially after cleaning the MAF. When cleaning the MAF, the very first thing you do is disconnect the battery, -then clean. Just give a 1/2 hour or so, then reconnect the battery. That reboots the program.

BTW- I recall some guys getting those codes in the Mustang Forums with the Drive by wire systems. All they had to do is reboot. Like I said, it may work and it may not.

Blue, Labnerd have covered other good possibilities. Simple stuff first, if that don't work,-go from there.

Wait, - You have a 2002 5.4L. I don't know why, but I was thinking you had a 3 valve. This isn't common with a 2 valve 5.4L, but you still have to reboot after cleaning the MAF. Revving up and shifting funny at highway speeds is usually a TPS problem. It goes MAF~TPS~Transmission as far as communication.

!! You soldered right to the sensor ? Yea, you can't do that with the TPS. Inside the TPS housing is ribbon wire, you most likley know what that is and yes you melted the ribbon soldering. The ribbon starts right after the terminal, then coils into a circle. So yea, it's right there.!! Replace that sensor for sure, -if you need a Pigtail, you can get those here http://www.fordparts.com/Default.aspx and order from this Pigtail PDF catalog -

http://www.fordtechservice.dealercon...torcatalog.pdf

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P0122 Throttle/Pedal Position Sensor A Circuit Low
P1122 Throttle Position (TP) Sensor Inconsistent With MAF Sensor Low Voltage
P1125 TPS Intermittant

So yea, something is wrong, -be it sensor, wiring or both. I think the sensor is wasted from soldering, because it wouldn't take that much heat to melt the ribbon and you still have an initial wiring problem within the MAF and TPS circuits. Check the MAF wires themselves/then circuit wiring. Check continuity, those damn wires can separate inside the insulation. Keep going, the problems there, you'll find it.

Keep us updated and feel free to keep asking questions.

Good Luck

 

OK, replaced TPS, connector, and MAF sensor. Also rebooted the KAM but the problem is still not fixed. Although it does seem to be more responsive to pedal position, it still revs up while driving in overdrive. Now it is giving me P0122, P0123, and P01125 trouble codes. I don't know what to do now.

 

Researched a little for yuh. Check the harness for a short/rubbing somewhere. Check right above the AC accumulator. Here's a few links for reference on your (VRef) meter.

http://www.obd-codes.com/p0122

http://www.obd-codes.com/p0121

Every wire needs to be gone thru I'm afraid. I know, -a PITA, but I would do that before I take it in.

Worst case scenario = Water has found it's way into the dash and is leaking on top or your PCM.

Search "F150 P1125" for other info as well.

Good Luck, -keep us updated and feel free to ask anything.

 

One more thing. Check your grounds on the firewall. You should have 3 visible. Special attention to the one over by the battery box next to the fender well.