# 2001 Civic Transmission Control Module electrical problem **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** civic, honda\ **Created:** [January 20, 2018, 8:41pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524 "2018-01-20T20:41:39Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![matteous](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@matteous](https://community.cartalk.com/u/matteous)\ **Post date:** [January 20, 2018, 8:41pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/1 "2018-01-20T20:41:39Z")
Hello, I got a 2001 civic LX automatic transmission. I did replace the transmission on it BUT now there is a check engine light comes on and the code reader says P0740 “Torque converter clutch solenoid circuit/Open” it seems like a an electrical problem. up on the information I got from the internet I have replaced Torque converter clutch solenoid, thermostat, engine coolant temperature sensor and fan temperature sensor on the thermostat body. Still I got the check engine light coming on. Anyone out there knows exactly what might be wrong? ---
**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\ **Post date:** [January 20, 2018, 8:52pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/3 "2018-01-20T20:52:34Z")
Have you checked the TC clutch solenoid connector? Can you feel the clutch engage and RPMs become steady at a constant speed? ---
**Author:** ![COROLLAGUY1](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/corollaguy1/32/7575_2.png) [@COROLLAGUY1](https://community.cartalk.com/u/COROLLAGUY1)\ **Post date:** [January 20, 2018, 9:27pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/4 "2018-01-20T21:27:21Z")
If there is no drivability issues with your car,disconnect the battery for a couple of hours or [overnight.to](http://overnight.to) clear the CEL. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [January 20, 2018, 9:31pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/5 "2018-01-20T21:31:50Z")
Before you disconnect the battery on your Honda, you might want to read this first. [http://www.aa1car.com/library/battery\_disconnect\_problems.htm](http://www.aa1car.com/library/battery_disconnect_problems.htm) Tester ---
**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\ **Post date:** [January 20, 2018, 10:23pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/6 "2018-01-20T22:23:03Z")
I never had a problem disconnecting the battery when I had an '01 Civic. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [January 21, 2018, 1:03am UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/7 "2018-01-21T01:03:28Z")
That’s for the TC lock-up function. It improves mpg, but worse case you can probably make do without it working if you can’t figure out how to fix the problem. The solenoid is just a coil of wire, electrically speaking. When current flows in that wire it creates a magnetic force and activates the solenoid valve. What the codes is saying is that the computer believes that coil’s continuity is broken somewhere, and so it won’t conduct electricity. The disconnection could be inside the solenoid, but it could also be from the computer to the solenoid, or the ground from the solenoid to the chassis ground. So break it into three sections. Easiest is to check section number 2, the solenoid itself. The coil of wire inside the solenoid should measure less than 30 ohms I’d guess. Since this is a replacement transmission, double check that the transmission is properly grounded to the chassis too. Another idea, try Googling “Hot Rod to the rescue transmission solenoid” . They had an article on a similar problem in the last few months. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [January 21, 2018, 6:19pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/8 "2018-01-21T18:19:46Z")
George, if you’re talking about what you mentioned a few days ago, that article was about a highly modified car It was also a completely different scenario ---
**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\ **Post date:** [January 21, 2018, 10:30pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/9 "2018-01-21T22:30:33Z")
> [@George\_San\_Jose1](#): > > …worse case you can probably make do without it working if you can’t figure out how to fix the problem. Non-working TC clutch should eventually throw a check engine light. (It did on my old Civic when a TC seal failed.) ---
**Author:** ![matteous](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@matteous](https://community.cartalk.com/u/matteous)\ **Post date:** [February 3, 2018, 11:57pm UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/10 "2018-02-03T23:57:32Z")
There is no drivability issue with the car as far as I can tell. did disconnect the ECU fuse in the engine compartment to clear the code but it kept coming back. I think i will follow up with George`s recommendation. Check the ground connection from transmission to chassis. ---
**Author:** ![matteous](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@matteous](https://community.cartalk.com/u/matteous)\ **Post date:** [February 4, 2018, 12:01am UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/11 "2018-02-04T00:01:36Z")
There is no drivability issue with the car as far as I can tell. did disconnect the ECU fuse in the engine compartment to clear the code but it kept coming back. I think i will follow up with George`s recommendation. Check the ground connection from transmission to chassis. I already changed the solenoid multiple times, thanks to Junk yards. ohh, the solenoid, it is the single one on top of the transmission correct? Do i need to check the shifting solenoids in the bottom also? and how about the linear dual solenoids? do they need to be checked? ---
**Author:** ![matteous](https://avatars.discourse-cdn.com/v4/letter/m/e5b9ba/32.png) [@matteous](https://community.cartalk.com/u/matteous)\ **Post date:** [February 4, 2018, 12:02am UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/12 "2018-02-04T00:02:34Z")
seems like there is no drivability issue with the car. drives and shifts fine… ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [February 4, 2018, 12:30am UTC](https://community.cartalk.com/t/2001-civic-transmission-control-module-electrical-problem/111524/13 "2018-02-04T00:30:34Z")
Disconnect the solenoid (if that’s easy to do) and measure its internal coil resistance. What do you measure (in ohms)? If the trans fluid level is low or dirty of course fix that problem first. If the solenoid seems the correct resistance, consider that harness wiring to it is open or shorted. The transmission must be properly grounded to the chassis for the solenoid to work correctly.