1996 Subaru OBII codes P0130, P0400 and P0740

I own a 1996 Subaru Legacy Outback with a 2.5L, auto with 164k miles. It has an extremely hard shift from 1st to 2nd gear and keeps down a gear at highway speeds. RPMs jump from about 2,800 to 4,000 at 70 mph. All oil, trans. fluid and coolant are fresh and none of the old fluids were burnt or rust filled.

I checked out an OBDII scanner at the local parts store and I get three codes. P0130 "O2 sensor circuit malfunction", P0400 "EGR flow malfunction and P0740 "TCC circuit malfunction"

I was hoping to find a way to repair without replacing every sensor listed and am particularly concerned about the words "circuit malfunction" does that mean there could be more than one item in the circuit gone bad?

Any suggestions would be appreciated.

MMM

Well, the first two codes wouldn't affect the way the tranny shifted. The TCC circuit malfunction makes sense because you said the RPMs are higher than normal at speed, so the TCC is not engaging properly. You'll probably need to take that to a good shop because you def. don't want to drive around with the TCC disengaged. It creates heat and friction and eventually, the tranny will overheat. TCC malfunction wouldn't cause a hard 1-2 shift, at least any that I could fathom. Has your MIL been on for a while? It's unlikely those codes all popped up at once!

My eldest son (23) had been driving the Subaru for several months and my guess is that the check engine light has been on for quite some time. The last time I was driving it the check engine light would come on so I took it into a shop. The mechanic got an EGR failure so he replaced the EGR and reset the computer. The check engine light would reappear after a day of driving the car, which was less then 50 miles. I noticed a few comments from other Subaru owners who have the same hard 1-2 shift and as I recall taking it to a specialty shop was the recommendation. I am pretty sure that is the direction I am heading on this one, but was hoping to be able to figure out the intermittant P0400 code and the steady P0130. I am not sure what part of the O2 circuit is the malfunction or simply replacing the sensor will do the trick. I traced the wires from the sensor and there does not appear to be any burnt insulation or shorting out.

so a new 02 is probably a safe guess but get it to a tranny shop asap or 02's will be the least of your worries!

Thanks Jeff. I'll do that and after I get the Subaru out of the shop I will let you know the outcome.

yeah, youre welcome

The transmission shop was a bust as they did not have the higher tech version scanner that only the dealer had. I caved and had the dealer scann the car and got corfirmation on the O2 sensor, the torque converter clutch solenoid and the coolant temp. sensor all needed to be replaced. Naturally the dealer also found leaking valve cover gaskets in addition to a wright pin inspection plate gasket. Rather than shelling out the nearly $2,500 for the repairs I ordered most of the parts online and after a brusing weekend completed all of the critical repairs. It was great to drive to work this morning and have the transmission shift like it should.

Thanks for the help.

Mountain Man=1 Dealer =0 I love happy endings (well less financially binding endings) congrats

I work on caravns continuously what the hell is a wright pin inspection plate gasket?

Comp, its a Subaru. But yeah, what is that anyway?

Was hoping you knew!

I think it's part of the Flux Capacitor

^ *grin*

hell dont feel bad i work on subies and i dont know wht the hell a wright pin inspection plate is th only thing i can guess at is what subaru calles a pcv plate its on the back of the motor block under the flex plate on the right hand side and very prone to leaking(unfourtuanly you have to pull the trans to reseal it)