Home Forums Articles How To's FAQ Register
Go Back   Xoutpost.com > BMW SAV Forums > X5 (E53) Forum
Bimmer Tool Rental
User Name
Password
Member List Premier Membership Search Today's Posts Mark Forums Read


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-16-2017, 10:02 AM
CleanIsFast's Avatar
Premier Member
 
Join Date: Jul 2009
Location: Arlington, VA
Posts: 483
CleanIsFast is on a distinguished road
Exclamation Informational: P0741 - Torque Converter Clutch Circuit Performance or Stuck Off

Background: I've seen this code pop up about 5 or 6 times over past 3-4 months. First time I ever saw it was going up a hill (light at the top of the hill), left off the gas to coast to the light prior to braking and it came on. This is the only time it's ever came on for me. I've driven hundreds of miles and the code is not there. On the other hand, my wife drives this vehicle daily (and puts on a lot of miles). Code has appeared a few times for her, but I haven't been in the vehicle to see what she is doing for the code to appear. So, I clear the codes and wait to see if it comes back on. Recently, she'll tell me in the morning the code is back, but in the afternoon it's gone without it being cleared

I've been doing a lot of research and see a ton of different things could be going on. Below will be complication of common symptoms, and possibly what to do. I can not afford to drop $4k+ on a new Transmission/TC, it's just not in the cards. I am hoping it's something simplier that can get me by for the next couple years. I've read that people were able to source reman TC for about $300.

Code: P0741 - Torque Converter Clutch Circuit Performance or Stuck Off

The P0741 fault code could be due to a problem within the lock-up clutch itself or the hydraulic control circuit within the transmission control valve body or the electrical control circuit or solenoid that operates the hydraulic circuit via the valve in the valve body. Additionally, the fault could be as simple as a corroded (or fluid soaked) harness connector plug at the transmission (where the vehicle electrical harness connects to the transmission)

Symptoms
- Check Engine Light will illuminate
- Vehicle will not shift into the highest gear at freeway speed
- Decrease in fuel economy
- In some cases, there may be performance problems, such as dying when coming to a stop after driving on the freeway and/or misfire-like symptoms

Common Problems That Trigger the P0741 Code
- Defective Torque Converter Lockup Solenoid
- Defective Engine Coolant Temperature Sensor
- Defective Torque Converter Clutch
- Defective Valve Body
- Dirty transmission fluid that restricts the hydraulic passages
- Battery that may need to be replaced


When the code P0741 is set in the Powertrain Computer, it means that the Powertrain Computer or PCM is seeing greater than a 200 RPM difference between the rotational speed of the Torque Converter and the Transmission Input Shaft. When the Torque Converter Lockup Clutch engages, there should be a 1 to 1 ratio between the Converter RPM and the Input Shaft RPM.

Before the converter locks, you can slightly vary the accelerator and you can see the engine RPM vary slightly, without the vehicle speed changing. Once the converter locks up, if you slightly vary the throttle, the RPM will not change as it does with the converter unlocked.* It will act like a manual transmission.* If you press the throttle a bit more, the converter will unlock and you will see the RPM jump up a couple to a few hundred RPM. The P0741 fault code could be due to a problem within the lock-up clutch itself or the hydraulic control circuit within the transmission control valve body or the electrical control circuit or solenoid that operates the hydraulic circuit via the valve in the valve body.*Additionally, the fault could be as simple as a corroded (or fluid soaked) harness connector plug at the transmission (where the vehicle electrical harness connects to the transmission)

Note: The 4.4i and 4.6is E53s use different torque converters (260mm ‘F38’ & 280mm ‘L51’ respectively). ZF manufactured over 85k 4.4i transmissions but less than 11k transmissions for the 4.6is, so the L51 can be more difficult to source


Diagnosing: a P0741 code, it is important to record the freeze frame information

One should monitor the Converter RPM and compare that to Input Shaft speed RPM at greater than 45 MPH on a smooth, flat surface after the vehicle is warmed up and the fuel system is in a closed loop. Monitor how the Converter Lockup Solenoid responds to an increased amount of throttle. The Lockup Solenoid duty cycle should go to 0 percent when the Throttle Position Sensor is above 40 percent and should return to 100 percent when the throttle is returned back to 15 to 20 percent. The duty cycle should go to 0 percent whenever the throttle is fully released and the vehicle has decelerated below 30 MPH. The Lockup Solenoid duty cycle should go to 0 percent whenever the brake pedal is applied, regardless of speed.

When looking at the Toque Converter RPM versus the Input Shaft RPM, observe if the scan tool data has a Converter Slip Speed PID or Parameter Identification. This can be very helpful in the diagnosis of an intermittent P0741. If the Lockup System is functioning correctly, the Slip Speed value should never be above 50 RPM. Try gently depressing the throttle on a gradual incline above 45 mph. When doing this, the Slip Speed should not increase. If it does and the Lockup Solenoid duty cycle is 100 percent—meaning it is fully applying the converter clutch—then you know you have a slipping Converter Clutch

If the Slip Speed stays steady but the transmission Output Shaft Speed starts to decrease (along with the MPH), then you know that you have an internally slipping transmission, usually caused by worn Clutch Packs or Sprag 1-Way clutches. If the Slip Speed remains very high and the Lockup duty cycle is 100 percent, then it is likely that the Solenoid is defective, because the duty cycle is reporting that the PCM is commanding the Lockup System to apply, but there is no change. Even with worn out Converter Clutches, there is always some kind of Slip Speed reading. It may go very high whenever the throttle is applied, but there should be some kind of a RPM reduction between the Converter Speed and the Input Shaft speed that verifies the Lockup Solenoid and PCM are trying to do their jobs.


So, here’s what you should experience, if you run through a test to see if the converter is locking:

1) Shifter in D – Drive. Starting to move, you will be in 1st gear

2) Note shift to 2nd gear as you accelerate (as each gear is changed, RPM will drop by a few hundred RPM). Note shift to 3rd gear, 4th gear, 5th gear

3) Lighten up on the acceleration to transition to a steady cruise. Watch the RPM. Play with varying the rpm by a couple hundred RPM and note that the RPM changes but the vehicle speed stays fairly constant.

4) Back to steady state running (above 45mph) and note when (if ) the converter locks up and the RPM drops by another 200 to 300 RPM. At this stage, if you slightly vary the throttle (as in step 7) the RPM will not change.

5) Push on the throttle a bit more and the converter will unlock and put you back to step 7. If you push harder on the throttle, the transmission will downshift to 4th gear. If you lighten up, it will shift back to 5th … and then into lock-up. If you can not detect the lock-up, then the clutch is not functioning.


Vendors:
Go-Powertrain (Harrisonburg, VA)
ZFtranspart - Eriksson Industries (CT)
ImportPerformance - (Wayne, NJ)

So as you can see failures in valve body, solenoid, pump, computer, seal or sensors can cause this code to appear...
I hope this helps some people and please correct me if I am wrong in what I read or need to add information.
__________________
BMW X5 4.6iS Registry
BMW X5 4.8iS Registry

2000 E39 ///M5
2003 E53 X5 4.6iS - My Progress Thread
2011 E70 X5 35d - Wife Mobile My Progress Thread
2006 E83 X3 3.0i MSport - Gone but not far
Reply With Quote

Sponsored Links

  #2  
Old 02-16-2017, 06:32 PM
Premier Member
 
Join Date: Jun 2015
Location: Southlake, Texas
Posts: 1,762
X53Jay4.8is is on a distinguished road
You are probably going to need a new TC at minimum. You can get a rebuilt one or you can still get a new one from BMW. I do have a new one for 4.6is that I special ordered for a client. The vehicle met in an accident and never received the TC change and customer never came back for part. PM if you have an interest.
Reply With Quote
  #3  
Old 02-17-2017, 04:31 AM
Member
 
Join Date: Jan 2011
Location: Blackburn UK
Posts: 302
RRPhil is on a distinguished road
You could also do an EDS 4 solenoid swap with one of the other EDS (black cap) solenoids and see if the problem moves with it.



The only way of isolating the culprit, without resorting to blind substitution, is to measure what’s going on. Is your diagnostic kit capable of recording the engine and turbine speeds and the EDS 4 current? That way you can analyse and diagnose the situation properly?



Phil
Reply With Quote
  #4  
Old 02-20-2017, 12:56 PM
smokeyyank's Avatar
Member
 
Join Date: Jan 2017
Location: Colorado
Posts: 103
smokeyyank is on a distinguished road
Welp mine just threw this code again. Had been driving fine and Saturday night it popped up. Going to do a tranny service hopefully soon, see what that does. The TC is just not locking up, at time it feels like it's hunting for a gear and on the highway it just drops RPM once the gas is let off. I have a feeling will need a new TC or may just say screw it and get a tranny. Found a place in CA that does rebuilds for $2,700. Not what I was planning on.......
__________________
Current garage:
'03 4.6is
'93 Jeep Cherokee (XJ)
'07 Jeep Liberty (KJ)
'08 Civic Si

Former garage:
'08 Mercedes C350
'08 Chevy HHR SS
'95 Mitsubishi Eclipse GSX
'90 Chevy K5 (Full on monster truck)
'89 BMW 325ic E30
'75 GMC Jimmy (Full restoration)
'76 Jeep CJ7 (Full restoration)
'74 GMC Jimmy (trail rig)
Reply With Quote
  #5  
Old 02-20-2017, 03:43 PM
srmmmm's Avatar
Member
 
Join Date: Jun 2013
Location: DFW, Texas
Posts: 659
srmmmm is on a distinguished road
Make sure you check the harness connector to the transmission as well. Mine would throw bogus codes going through a car wash because of the dirt and grime that made its way into the socket.

2002 X5 3.0 317,600 miles
2014 428i 26,000 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird Under restoration
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On





All times are GMT -4. The time now is 12:38 PM.
vBulletin, Copyright 2017, Jelsoft Enterprises Ltd. SEO by vBSEO 3.6.0
© 2017 Xoutpost.com. All rights reserved. Xoutpost.com is a private enthusiast site not associated with BMW AG.
The BMW name, marks, M stripe logo, and Roundel logo as well as X3, X5 and X6 designations used in the pages of this Web Site are the property of BMW AG.
This web site is not sponsored or affiliated in any way with BMW AG or any of its subsidiaries.