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Guest Message by DevFuse
 

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1998 legacy outback showing a p0740 code


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9 replies to this topic

#1 gunther4272001

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Posted 22 July 2014 - 08:47 PM

My 1998 Legacy Outback is showing a p0740 code, the check engine light will come on for around four start cycles then goes back off. Comes back on again after a few more start cycles any ideas



#2 john in KY

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Posted 22 July 2014 - 09:40 PM

http://www.obd-codes.com/p0740



#3 MilesFox

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Posted 22 July 2014 - 11:54 PM

The code is related tot he torque converter lock-up solenoid.



#4 Fairtax4me

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Posted 23 July 2014 - 12:04 AM

Possibly the wiring for the TCC solenoid inside the trans is chafed or pinched and is shorting. Very little clearance between the pan and the valve body and there are several wires and solenoids in there that can be damaged if something pushes against the pan.

I would unplug the large connector for the trans wire harness up by the firewall and check for corrosion there first. Then check the harness where it runs down the side of the trans for chafed wires. If that's clean the pan will probably need to be dropped to check the wiring inside the trans.

Edited by Fairtax4me, 23 July 2014 - 12:04 AM.


#5 johnceggleston

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Posted 23 July 2014 - 05:30 PM

is the oil pan on the trans dented??????



#6 gunther4272001

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Posted 24 July 2014 - 07:21 AM

doesnt look dented and is now not shifting to overdrive. someone told me to check the tps sensor dont see how that would do anything never know though



#7 gunther4272001

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Posted 26 July 2014 - 11:55 AM

changed the tps sensor and the light went out and shifted into overdrive again. light hasnt came back on but stopped shifting into overdrive again could there be a code stored in the computer?



#8 Fairtax4me

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Posted 26 July 2014 - 12:18 PM

Possibly a fault with the TCC solenoid in the trans. I still think you need to pull the pan.
You won't get circuit fault codes for the lockup solenoid because of the TPS.

#9 gunther4272001

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Posted 26 July 2014 - 12:25 PM

just seemed funny changed the tps the light went out and was shifting again. hasnt came back on since usually comes back on within a few starts


Edited by gunther4272001, 26 July 2014 - 12:26 PM.


#10 gunther4272001

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Posted 14 August 2014 - 08:55 PM

the trans started shifting again but does it intermittingly will shift fine for short times then stops. Transmission guy said sounds like a wiring problem any ideas where to start at






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