P0740 (no symptoms)
P0740 (no symptoms) I'm going to post this here as well as it may get more advice than just in the PCM section:
This is an odd one- I've been reading up on it and I can't seem to get any solid definitive answers on it if you don't have symptoms. It seems that everyone who throws this code has noticiable transmission symptoms
I'm throwing P0740 in my 2002 ls1 camaro (stock 4L60e / stock stall) and I have no sympoms- my car shifts fine, 1, 2, 3, 4 and I am pretty sure it locks up as the rpms stay low enough? Although I am not 100% sure unless I scan it
Shifts aren't harsh, I do have a bit of a misfire, but Ive had that since last year and I am pretty sure it is from the back most spark plug that was the only one I couldnt get to to change (but will be sometime this summer)
Does anyone have any ideas of where I should start looking if I am not showing any symptoms other than the code (everytime I clear it and go for a short drive it comes back)
I just got back from a 6 hour road trip (each way) and she was beautiful- I reinstalled my wideband O2 sensor today and found out the sensor is fried, then right after I got this TCC code, I pulled the fuse out for the gauge just incase it is an electrical issue, but that doesnt seem to fix the problem.
I can scan it with hp tuners tonight- but what do I scan for? input/output shaft speed variation? what else? are there tests I can run with hp tuners to rule things out?
Help!
This is an odd one- I've been reading up on it and I can't seem to get any solid definitive answers on it if you don't have symptoms. It seems that everyone who throws this code has noticiable transmission symptoms
I'm throwing P0740 in my 2002 ls1 camaro (stock 4L60e / stock stall) and I have no sympoms- my car shifts fine, 1, 2, 3, 4 and I am pretty sure it locks up as the rpms stay low enough? Although I am not 100% sure unless I scan it
Shifts aren't harsh, I do have a bit of a misfire, but Ive had that since last year and I am pretty sure it is from the back most spark plug that was the only one I couldnt get to to change (but will be sometime this summer)
Does anyone have any ideas of where I should start looking if I am not showing any symptoms other than the code (everytime I clear it and go for a short drive it comes back)
I just got back from a 6 hour road trip (each way) and she was beautiful- I reinstalled my wideband O2 sensor today and found out the sensor is fried, then right after I got this TCC code, I pulled the fuse out for the gauge just incase it is an electrical issue, but that doesnt seem to fix the problem.
I can scan it with hp tuners tonight- but what do I scan for? input/output shaft speed variation? what else? are there tests I can run with hp tuners to rule things out?
Help!
I took a scan of a ride around the block- I scanned some status bits as well as some transmission parameters- the TCC solenoid seems to turn on and off?
Im attaching my config file and the scan for anyone to take a quick look?
Car still drives great, but as soon as I delete that code it comes right back- Im stumped??
trans codes.zip
Im attaching my config file and the scan for anyone to take a quick look?
Car still drives great, but as soon as I delete that code it comes right back- Im stumped??
trans codes.zip
Making progress- When I command the Torque converter clutch on with hp tuners when in gear and idling, the engine doesnt bog or stall out like it should. So I am guessing that the clutch is not actually being applied
I'm terrible at electrical diagnosis
Is it still possible this is an electrical problem within the transmission? Can I use Hp tuners to begin ruling out possible causes for the clutch not being applied?
I also found this article which is basically a diagnosis tree- unfortunately I don't have any of the tools it asks for (all electrical) but can hp tuners substitute a lot of the diagnostic devices being used becasue it can trigger solenoids etc?
Here is the article: http://www.hotrodlane.cc/New%20LS%20...%205.7%20L.htm
I'm terrible at electrical diagnosis
Is it still possible this is an electrical problem within the transmission? Can I use Hp tuners to begin ruling out possible causes for the clutch not being applied?
I also found this article which is basically a diagnosis tree- unfortunately I don't have any of the tools it asks for (all electrical) but can hp tuners substitute a lot of the diagnostic devices being used becasue it can trigger solenoids etc?
Here is the article: http://www.hotrodlane.cc/New%20LS%20...%205.7%20L.htm
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Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
The P0740 sounds like an electrical code and not a code due to slippage (like P1870). Therefore, I would start by doing a continuity test (ohm meter) on the two TCC solenoids. The main TCC solenoid is bolted into the pump and wired into the harness. To replace it you either have to buy a new internal harness ($40) or a replacement solenoid ($15?) that you splice into the existing harness.
ya there are no other codes- so my next steps are drop the pan, and test the electronic harness and solenoid. refresh my memory, do I need to drop the valvebody to change the harness and or solenoid? (Im hoping not, those checkballs do not like to stay in one spot, it was easy to install a shift kit in my old car with the trans out, I can't imagine being upside down trying to install those little ***** and have them stay put)
Is there anything else that it could be? pcm or wiring from the pcm to the trans? could the issue be within the torque converter? or would that throw additional codes?
Is there anything else that it could be? pcm or wiring from the pcm to the trans? could the issue be within the torque converter? or would that throw additional codes?
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
You do NOT have to drop the valve body. Just the pan and filter.
It could be wiring from the PCM to the trans, but test the two TCC related solenoids first.
It is electrical - so not likely a problem with the converter.
It could be wiring from the PCM to the trans, but test the two TCC related solenoids first.
It is electrical - so not likely a problem with the converter.
