DTC P0740 torque converter clutch circuit / open

CASHJACK

MEMBER
2003 CHEVROLET TRAILBLAZER
4.2L
6 CYL
2WD
AUTOMATIC
246,000 MILES

Changed out the ignition switch module under steering wheel. Drive vehicle 8 m. Turn off. Wait. Start back. Check engine light. Dtc p0740. Before change ignition switch module. Went thru routine of driving. Turn engine off. Startup. Check engine light dtc p740. Clear code. Can only drive one time. Code comes back. I believe alarm is factory. How do I tell? Bought vehicle used 4 yrs ago. Wiring check to fuse, trans? Thanks

Wednesday, August 26th, 2015 AT 7:10 PM

2 Replies

WRENCHTECH

MECHANIC
20,761 POSTS

You have a problem with a transmission control circuit. Why are you looking at a ignition switch?

If the solenoid turns out to be the problem, that is internal to the transmission so I suggest ou have a trans specialist look at it.

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Thursday, August 27th, 2015 AT 2:10 AM

CASHJACK

MEMBER
17 POSTS

Before changing ignition switch, I found a article on this website pertaining to this problem, since then I hav not been able to find that article. On other website, found that ign2 white wire is loose, chaffed error codes and transmission problems will occur.

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Sunday, August 30th, 2015 AT 6:48 AM