: The dreaded weekly P0741 engine code & a fix



1BAD4CAM
01-19-11, 12:23 AM
I will try to deep this post short, but for 5 yrs I never had any type of DTC other than the ocassional Knock Sensor (p0327) due to a heavy right foot on my 2000 ETC. Over the last couple of yrs the dreaded P0741 (TCC stuck on) code would pop up every few weeks, & during the last yr. it was at least weekly, sometimes twice a week. As this car has less than 100k & is in factory condition I didn't want to have to pull the engine & trans assy. to repair the faulty solenoid. About two months ago I decided to put in a new throttle position sensor (tps) as in most cars the tps provides input to the ECU which controls transmission shifting. As others have stated in the forum, they get the 741 code and the car seems to perform & shift into OD as it should. All I can attest to is that after I replaced that $40 tps sensor I have not gotten another p0741 in the past two months. For those of you that have had that recurr:cool2:ing code with no other symtoms it might be a fix for you. Maybe the more Tech Savy guys in the forum (Submariner & Ranger) can comment on that fix, but for me it was a "lights out" dash from that point on.

Ranger
01-19-11, 12:08 PM
Over the last couple of yrs the dreaded P0741 (TCC stuck on) code would pop up every few weeks,
P0741 is actually TCC stuck OFF. If it where stuck on, you'd stall every time you came to a stop.

I see no relationship between the TPS and the DTC. What made you change the TPS? My guess is that the code will rear it's ugly head again, but keep us posted. Your results so far are interesting to say the least.

1BAD4CAM
01-19-11, 12:34 PM
Thanks for the comment Ranger, I replaced the TPS for 2 reasons----1 I have a jeep cherokee that would shift down a gear at cruising speed (70mph) on the freeway, and at times not downshift properly when climbing hills under load. I thought it was the control body in the trans & took it in for diagnosis. End result was a faulty TPS providing bad input to the PCM causing all the problems. Replaced the TPS & that cured the irreverent shifting. 2 At times when running about 60 the ETC would hesitate a little before disengaging the lockup when accelerating. With the viscuous coupling it is difficult sometimes to notice the disengagement. Knowing that the TPS provides input to trans control I thought it would be a cheap attempt to provide a solution. And it has been 2 months since I have had any DTC's.
Thanks again

Submariner409
01-19-11, 01:20 PM
Interesting set of findings. The TPS does send part of the load/power signal to the PCM, so I guess it's possible that there might be some interaction with TCC control: that HAS to drop out upon power demand. The TCC itself will not handle full engine power into the transmission.

Ranger
01-19-11, 02:06 PM
Interesting indeed, and no TPS codes?

1BAD4CAM
01-19-11, 02:36 PM
Nope----Never got any TPS codes----just the TCC. Only difference that I noted after I replaced the TPS was as I said, a little smoother when unlocking and accelerating in the 50-60 mph range.

Submariner409
01-19-11, 03:00 PM
This is a stretch, but this problem occurs in many types of variable resistors: Say you have a volume control, light dimmer, fan control, fuel level sensor, TPS - all variable resistors. Say you always keep the control set at some nominal (habitual) position - like using Cruise Control at 60-63 mph all the time. That variable resistor develops oxidation, corrosion, "tracking" or some other electrical problem because it's always hunting within a narrow band. Like on a radio volume control that gets "scratchy" - you twizzle it back and forth a few times to clean the contacts. .......Might apply here, too.

You can use TECHRON to clean a fuel level sensor (sometimes), but a TPS is sealed. I wonder if operating the gas pedal, therefore the TPS, throughout its full travel several times a week with the key OFF would tend to clean the wiper and resistor strip ??

1BAD4CAM
01-19-11, 06:20 PM
Everything that is mechanical is subject to wearing out. I assume that the linearity of the resistance is affected by the rheostat operating in the same 2-5 degrees of rotation for long periods of time while commuting, and maybe a "resistance flat spot" is created in the output.

tateos
01-19-11, 09:42 PM
Everything that is mechanical is subject to wearing out. I assume that the linearity of the resistance is affected by the rheostat operating in the same 2-5 degrees of rotation for long periods of time while commuting, and maybe a "resistance flat spot" is created in the output.


Yet another excuse for WOTs!

Ranger
01-19-11, 10:10 PM
This is a stretch, but this problem occurs in many types of variable resistors: Say you have a volume control, light dimmer, fan control, fuel level sensor, TPS - all variable resistors. Say you always keep the control set at some nominal (habitual) position - like using Cruise Control at 60-63 mph all the time. That variable resistor develops oxidation, corrosion, "tracking" or some other electrical problem because it's always hunting within a narrow band. Like on a radio volume control that gets "scratchy" - you twizzle it back and forth a few times to clean the contacts. .......Might apply here, too.

You can use TECHRON to clean a fuel level sensor (sometimes), but a TPS is sealed. I wonder if operating the gas pedal, therefore the TPS, throughout its full travel several times a week with the key OFF would tend to clean the wiper and resistor strip ??
My guess (and it is just that) is yes.

MBombace
01-20-11, 08:27 AM
I am glad to hear you fixed your problem! I have same problem and was wondering if you can send the step you took to make the repair by yourself.

Ranger
01-20-11, 12:15 PM
Mbombace, let us know what your outcome is. Inquiring minds want to know.