CoolAirVw
Vendor
A tale of two $hitties....
Here's 01M part 2 http://forums.tdiclub.com/showthread.php?t=250194&highlight=01m
I promised a good one for 01M part 3, and here it is (two actually).
------------------Test case #1--------------------------------------------------------
A club member contacted me about a car he had purchased. He brought it to me and left it with me to checkout. He was getting a code 01192 (P0740 generic) for Torque Converter Clutch (TCC) mechanical malfunction. On hot trips, intermittantly he would trigger the code and the TCC would stop coming on. This would translate into higher than normal RPM's on the hiway. This is acutally a "failsafe" stategy. When the computer triggers the code it stops commanding the TCC on. Of course on our diesels with very narrow rpm band it would seem like the engine is racing like crazy. Most people would describe this as "No 4th" or "Slips real bad on hiway" or "No overdrive", due to their lack of understanding.
This is what I graphed on Franks car.
Refer to 01M part 2 for background details about TCC.
I would like to suggest that if you are having a TCC problem graph the TCC slip and the engine RPM from group seven. Set the scale on the tcc slip to Max 900 and Min -100 (thats negitive 100).
Remember from 01M part 2 that the green spikes are shifts. Last spike on on the right is the 3-4, then slip drops to zero, as the computer commands TCC on. Remember zero is not the bottom of the graph for the TCC. Zero is the lowest graticule, when scale is set as I suggested.
The upward ramp and plateau in the 7th and 8th field happen as I step into the throttle,to load up the TCC, to see if it will hold. Each stair step higher represents me stepping in the throttle a little more. This is TCC slip. This is not normal. This car would very intermittantly trigger the code but it would slip most every time when loaded in this way. Loading it up, in this way, while going uphill would be the best check for TCC slip.
You may notice the slight increase and plateau in the 4th frame. Very slight increases on the graph ARE normal. It seems vag-com, or the TCM only read slip in intervals of 15. So slip that graphs up to 15 or even 30 for small periods is not necessarily a problem. (more on that later)
update Edit: 12-12-2013 In this car I bored the TCC valve bore oversized and installed one valve. Of course later I found other cars with wear on other valves and now when I do these I overbore and install oversized valves for all 4 that are available.. As of now I have done about 200 of these with nearly 100% success in fixing TCC codes. Disclaimer: Sometimes the trans itself (ie 4th gear clutch pack or others) can slip and the computer might interpret it as TCC slip and trigger TCC slip codes. You would know this as you would feel the slip and see the slip in the tach, and it would be more than a few hundred rpm that a TCC slip can cause. Read 01m part 6 for more info. Valve body work wont fix all slips. Your trans could be slipping and failing, and you coul also have a TCC slip code and VB work may not fix the entiretly of the problem.
Frank took his car home, removed the Valve Body (VB) and sent it to me. I did some vacuum testing on the TCC valves and they were very worn. After reboring and installing new TCC valves the vacuum tests were fantastic!
I sent the VB back to Frank and it was reinstalled and has been thoroughly driven now to confirm the fix.
Frank's TCC valve was worn, allowing the pressure that applies the TCC to "leak" or "fall into the pan", causing not enough pressure to hold the TCC applied under load, triggering the trouble code. The problem is there are other areas that can cause this. If other area's in the trans were worn allowing that same pressure to leak, then you would have the same code. Also the converter itself can cause this. I'll say it bold so everyone understands.
There is no test to determine where your pressure loss is, that is causing your TCC code, other than physical disassembly, visual inspection and testing individual components for pressure loss.
Brian (oilhammer) might say this may not be a lasting repair. To this I partially agree, in that there is no way to test the TCC itself, nor is there a way to test the internal trans pressure that applies the TCC. But as a low cost repair its definitely worth a try. Edit at of 11-30-16 We have done tons of these and despite other potential causes P0740 is almost always the valve body. I would guess about 98% of the time. Now if you have other symptoms along with your P0740 I'm not saying it will fix your other symptoms, other than TCC inoperative or surging.
Note: lots of people contact me about P0740 codes and they define the code as TCC solenoid circuit. Lots of aftermarket sources INCORRECTLY define P0740 as TCC solenoid circuit. But P0740 is NOT a solenoid code. Meaning it is not a problem with the electrical circuit of the TCC solenoid. P0740 is defined by vagcom and other corrects souces as TCC mechanical malfunction or TCC slip. This means the computer sees a slip by comparing engine rpm to road speed, taking into account what gear the trans is in. See 01m part 5 solenoid for more info.
Test case #2 is the same repair, but I would consider it a fairly certain fix!
-------------------------Test case #2-----------------------------------------------
This car was brought to me before a vacation trip to fix a speedo/cruise problem. See this thread...http://forums.tdiclub.com/showthread.php?t=246679
After I repaired the speedo/cruise problem, I wanted to check over the car, before Melissa left on her trip. I noticed some surging. You could see it on the tach, and feel it. I took a video and will edit this post and place the video here later.
EDIT: VIDEO CONTENT ADDED
Watch the tach needle and listen to the sound of the motor. You can see and hear the rpms surging. On the video its slightly subtle but in the car its obvious.
This surging was actually pretty interesting. Understand that I work on all makes of transmissions, and I've felt TCC surging, TCC chatter, engine misses that people want to call TCC problems, and every other thing imaginable. This was interesting because as it would surge in and out, it would chatter as it released, then as it would reapply it would chatter, and this cycle would continue as you can see on the graph (never felt that before!) This made a subtle, hard to interpret sensation that confused me at first.
Well as everyone knows, one of the primary causes of TCC chatter is poor fluid condition. And of course with VW's "lifetime" fill, every 01M has nasty fluid condition, and this Beetle was no exception.
insert nasty fluid comparison picture here.....
After graphing the TCC slip it was plain as day.
You can see the surging TCC just before the 3-4 and lots after! Notice the corresponding changes in RPM. I should explain that what is happening here is the Tcc coming on and off without the computer commanding it. But the computer could command this to happen. If this were the case you would see the command changing in group 7, field 1. you cant check this with a graph, you have to look at the Data field.
I want to make clear that the surging can happen without the chatter and that TCC chatter can happen without the surging. The flush fixed the chatter and the valve fixed the surging. If you had chatter without the surging it would happen as the TCM commanded the TCC on or off, and you world only be able to feel it. you would not see it on the graph.
Melissa's TCC valve was worn and having trouble controlling regulation. In the past, at my suggestion of a experimental repair, two other members here tried to fix a surging problem by replacing the TCC boost valve and sleeve, and solenoid themselves, without reboring the VB. It fixed one but not the other. But, for definate surging that has been captured on a graph, with the rebore, I would consider this a fairly certain repair.
I'll probably edit later and add more info. Its late I'm tired. I have some vavle body pics and stuff...
Here's 01M part 2 http://forums.tdiclub.com/showthread.php?t=250194&highlight=01m
I promised a good one for 01M part 3, and here it is (two actually).
------------------Test case #1--------------------------------------------------------
A club member contacted me about a car he had purchased. He brought it to me and left it with me to checkout. He was getting a code 01192 (P0740 generic) for Torque Converter Clutch (TCC) mechanical malfunction. On hot trips, intermittantly he would trigger the code and the TCC would stop coming on. This would translate into higher than normal RPM's on the hiway. This is acutally a "failsafe" stategy. When the computer triggers the code it stops commanding the TCC on. Of course on our diesels with very narrow rpm band it would seem like the engine is racing like crazy. Most people would describe this as "No 4th" or "Slips real bad on hiway" or "No overdrive", due to their lack of understanding.
This is what I graphed on Franks car.
Refer to 01M part 2 for background details about TCC.
I would like to suggest that if you are having a TCC problem graph the TCC slip and the engine RPM from group seven. Set the scale on the tcc slip to Max 900 and Min -100 (thats negitive 100).
Remember from 01M part 2 that the green spikes are shifts. Last spike on on the right is the 3-4, then slip drops to zero, as the computer commands TCC on. Remember zero is not the bottom of the graph for the TCC. Zero is the lowest graticule, when scale is set as I suggested.
The upward ramp and plateau in the 7th and 8th field happen as I step into the throttle,to load up the TCC, to see if it will hold. Each stair step higher represents me stepping in the throttle a little more. This is TCC slip. This is not normal. This car would very intermittantly trigger the code but it would slip most every time when loaded in this way. Loading it up, in this way, while going uphill would be the best check for TCC slip.
You may notice the slight increase and plateau in the 4th frame. Very slight increases on the graph ARE normal. It seems vag-com, or the TCM only read slip in intervals of 15. So slip that graphs up to 15 or even 30 for small periods is not necessarily a problem. (more on that later)
update Edit: 12-12-2013 In this car I bored the TCC valve bore oversized and installed one valve. Of course later I found other cars with wear on other valves and now when I do these I overbore and install oversized valves for all 4 that are available.. As of now I have done about 200 of these with nearly 100% success in fixing TCC codes. Disclaimer: Sometimes the trans itself (ie 4th gear clutch pack or others) can slip and the computer might interpret it as TCC slip and trigger TCC slip codes. You would know this as you would feel the slip and see the slip in the tach, and it would be more than a few hundred rpm that a TCC slip can cause. Read 01m part 6 for more info. Valve body work wont fix all slips. Your trans could be slipping and failing, and you coul also have a TCC slip code and VB work may not fix the entiretly of the problem.
Frank took his car home, removed the Valve Body (VB) and sent it to me. I did some vacuum testing on the TCC valves and they were very worn. After reboring and installing new TCC valves the vacuum tests were fantastic!
I sent the VB back to Frank and it was reinstalled and has been thoroughly driven now to confirm the fix.
Frank's TCC valve was worn, allowing the pressure that applies the TCC to "leak" or "fall into the pan", causing not enough pressure to hold the TCC applied under load, triggering the trouble code. The problem is there are other areas that can cause this. If other area's in the trans were worn allowing that same pressure to leak, then you would have the same code. Also the converter itself can cause this. I'll say it bold so everyone understands.
There is no test to determine where your pressure loss is, that is causing your TCC code, other than physical disassembly, visual inspection and testing individual components for pressure loss.
Brian (oilhammer) might say this may not be a lasting repair. To this I partially agree, in that there is no way to test the TCC itself, nor is there a way to test the internal trans pressure that applies the TCC. But as a low cost repair its definitely worth a try. Edit at of 11-30-16 We have done tons of these and despite other potential causes P0740 is almost always the valve body. I would guess about 98% of the time. Now if you have other symptoms along with your P0740 I'm not saying it will fix your other symptoms, other than TCC inoperative or surging.
Note: lots of people contact me about P0740 codes and they define the code as TCC solenoid circuit. Lots of aftermarket sources INCORRECTLY define P0740 as TCC solenoid circuit. But P0740 is NOT a solenoid code. Meaning it is not a problem with the electrical circuit of the TCC solenoid. P0740 is defined by vagcom and other corrects souces as TCC mechanical malfunction or TCC slip. This means the computer sees a slip by comparing engine rpm to road speed, taking into account what gear the trans is in. See 01m part 5 solenoid for more info.
Test case #2 is the same repair, but I would consider it a fairly certain fix!
-------------------------Test case #2-----------------------------------------------
This car was brought to me before a vacation trip to fix a speedo/cruise problem. See this thread...http://forums.tdiclub.com/showthread.php?t=246679
After I repaired the speedo/cruise problem, I wanted to check over the car, before Melissa left on her trip. I noticed some surging. You could see it on the tach, and feel it. I took a video and will edit this post and place the video here later.
EDIT: VIDEO CONTENT ADDED
Watch the tach needle and listen to the sound of the motor. You can see and hear the rpms surging. On the video its slightly subtle but in the car its obvious.
This surging was actually pretty interesting. Understand that I work on all makes of transmissions, and I've felt TCC surging, TCC chatter, engine misses that people want to call TCC problems, and every other thing imaginable. This was interesting because as it would surge in and out, it would chatter as it released, then as it would reapply it would chatter, and this cycle would continue as you can see on the graph (never felt that before!) This made a subtle, hard to interpret sensation that confused me at first.
Well as everyone knows, one of the primary causes of TCC chatter is poor fluid condition. And of course with VW's "lifetime" fill, every 01M has nasty fluid condition, and this Beetle was no exception.
insert nasty fluid comparison picture here.....
After graphing the TCC slip it was plain as day.
You can see the surging TCC just before the 3-4 and lots after! Notice the corresponding changes in RPM. I should explain that what is happening here is the Tcc coming on and off without the computer commanding it. But the computer could command this to happen. If this were the case you would see the command changing in group 7, field 1. you cant check this with a graph, you have to look at the Data field.
I want to make clear that the surging can happen without the chatter and that TCC chatter can happen without the surging. The flush fixed the chatter and the valve fixed the surging. If you had chatter without the surging it would happen as the TCM commanded the TCC on or off, and you world only be able to feel it. you would not see it on the graph.
Melissa's TCC valve was worn and having trouble controlling regulation. In the past, at my suggestion of a experimental repair, two other members here tried to fix a surging problem by replacing the TCC boost valve and sleeve, and solenoid themselves, without reboring the VB. It fixed one but not the other. But, for definate surging that has been captured on a graph, with the rebore, I would consider this a fairly certain repair.
I'll probably edit later and add more info. Its late I'm tired. I have some vavle body pics and stuff...
Last edited:
