OBD code P2791 - any ideas?

OBD code P2791 - any ideas?

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MrH

Original Poster:

484 posts

215 months

Wednesday 29th April 2015
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Hi All

Whilst i await a call from a dealership, i thought i'd come here to tap into the PH fountain of knowledge!

We have a code P2791 "Gate Select Direction Circuit Low" on a 2006 F430 Coupe with F1 paddleshift. Has anyone had this before and if so what was the issue?

Car starts and works fine, then randomly throws the code (after 10 mins of driving this morning for examples), bleeps, then won't go above second gear in auto or paddleshift mode. Shutting off the car, leaving for 10 mins or so, and re-starting clears it, but it does come back.

Any ideas!?

Many thanks, Mark

kenyon

1,269 posts

264 months

Wednesday 29th April 2015
quotequote all
Check the hydraulic fluid tank may be low!!

Cerberaherts

1,651 posts

148 months

Wednesday 29th April 2015
quotequote all
You likely have a system pressure fault, perhaps caused by a failing E-diff solenoid or a pump issue. It will require proper diagnosis with an SD3 tester....

MrH

Original Poster:

484 posts

215 months

Thursday 30th April 2015
quotequote all
Thats guys

Have located the fluid tank back right of the car behind the panel. Is it just a case of unscrewing the cap and checking level? Or does anything have to be done before i take the cap off?

I understand there is a leveller inside which the fluid ideally must be 5mm above, rather than relying on the attached dipstick?

voicey

2,457 posts

194 months

Thursday 30th April 2015
quotequote all
Your OP indicated that the car was at the dealer but it appears not. Out of interest, how did you get the P2791 code out of the TCU?

To check the F1 fluid level use the dipstick in the cap when the car is cold (as the fluid expands quite a lot when it warms up). The unreliable dipsticks were fitted to the 360.

However, you'll be very lucky if this problem is caused by low fluid. You need someone who has experience with the F1 system and an SD3 to properly diagnose the cause - it could be one of many things, most of which cannot be fixed at home.

MrH

Original Poster:

484 posts

215 months

Thursday 30th April 2015
quotequote all
Havent gone to the dealer was simply awaiting a call from them with info.

Hooked the car up with an OBDII reader to get the code. Understandably anything more than a fluid check will need a dealer to take over but a few people have said to check the fluid first.

If thats not low, or if we top up and it doesn't solve, then indeed it'll be booked into a dealer.

Good to know we can use the dipstick, was just checking i didn't need to do anything before removing the cap as its linked to pressure and hydraulics!

Cheers, Mark

Cerberaherts

1,651 posts

148 months

Thursday 30th April 2015
quotequote all
Even IF the fault has been caused by low fluid level, (unlikely) then you have a leak. If sufficient fluid has leaked out that it needs topping up then you certainly shouldn't be driving it. Your obd tester won't generate any kind of meaningful fault code generated by the gearbox control unit, it isn't capable.