Limp mode -codes 1618, 733

[gary g]

2001 v70xc
230,000 miles

Tried to get off a patch of lumpy ice today and the car revved but went nowhere. Couldn't tell what wheel was spinning. Managed to nurse the car off the icy patch and into the driveway but it went to limp mode.

I let the car sit for a bit and seemed normal when I restarted it, but went back into limp after about 4 blocks. codes 1618 and 733.

1618 could be the PNP/Gear position sensor. 733 is a missing 3rd gear (I think). Haven't had any trouble w trans and fluid is more red than brown. Is it likely that this is just the gear pos sensor? Seems logical that if the computer doesn't recognize what gear its in, it will throw a transmission code.

Any idea why spinning wheels on ice would bring this on? Clearly the awd did not engage. Is that a cause or a symptom of all this?

Hope this all makes some sense. Appreciate any insights.

Thanks!

[gary g]

No takers on this one?
Update: I put in a used $10 gear position sensor. Worked for a few miles and then had to limp home at 20 mph. The 1618 code returned and instead of the 733, I got a 740 code, which relates to the torque converter solenoid. Is that solenoid in the valve body?
Any other clues to what the root problem is here?
Sounds like given the miles (230K) and the vague codes (1618, 733, 740) , a valve body would be logical, but I would want to be sure that will solve this.
On this car, I would have expected some warning signs of a failing trans before it just crapped out, but there were none, which makes me think it could be just one thing rather than a full valve body. Foolish logic?

[vtl]

The forum is mostly dead, you may get better luck at other two major Volvo forums.

Your problem sounds like a clogged filter, which causes pressure loss and slippage in gears. The transmission is tossed. The reason why the filter initially started to clog is a toss event already.

[Astro14]

With all transmission performance issues, I start by making sure the that the fluid is at the proper level and in good condition. I don't know much about those codes, but I would start with a drain and fill, examine the fluid condition, and be certain the level is correct.

At 230,000 miles, however, this may be a lot more involved than just a fluid issue.

[gary g]

Thanks for the responses.

I have read a lot on other sites and it does sound like a clogged screen. Comtemplating the Procopster fix from MVS if it gets to that point, but here is my update:

I hooked up VIDA and cleared everything since there were a million codes from who knows how long ago.
Transmission reengaged after sitting for a few days and worked fine until heated up and then was barely sifting at all, but no dash codes, and nothing in VIDA. I am new to VIDA so I don't know if I exhausted the diagnostics in there. (I could not seem to activate any modules. Maybe you need the subscription for that?)

For those who don't know about the clogged-screen problem: Particles in the fluid fall off the filter to the bottom allowing the trans to work until the particles again clog up the screen and kill the fluid pressure.

A couple ways to verify that this is the problem:
Pull the return hose from rad and check flow. If it is a trickle, chances are good that’s the problem
Listen for a whine from the trans, which is the pump getting starved for fluid. In my case, this is tough to hear because the PS pump has been on the way out and making a racket for a while.
From what I read, the clogged filter problem does NOT throw a code

There is a way to address this by drilling a hole in the bell housing, inserting a skewer into the filter and puncturing the screen. See Matthew’s Site for details. Sounds a little savage, but it seems to get the car back on the road for a while, maybe longer, but only if this is the problem. Also, as Astro points out, I know this might not be the ONLY problem, but it did shift great before this. Also need to add an inline filter if I go that route.

So my plan is this:

Test the pressure by pulling the hose
Flush the fluid (of course). But I doubt this will suffice
If none of this works, consider the Procopster band-aid

Unless there is anything else I can do in VIDA?

thanks!

[gary g]

Well I gave it a good Gibbons-ish trans flush and so far so good. Fluid was much dirtier than I thought. Driving it locally for a while and it is shifting about 90% as well as it did before -even after getting it up to temp. Next up, a little time on the highway. I
t would be nice if I can avoid having to drill the bell housing...

[Astro14]

If it’s better with new fluid, then you’ve done well. Drive it for a bit, then do your “gibbons-ish” flush again. Might try a bit of either solvent, or ester-based synthetic, as both will dissolve deposits internal to the transmission. Either “trans-tune”, or “lubeguard”, or, if you like, something like AMSOIL transmission fluid.

[gary g]

hmm. So add the solvent now, then drive it a while, then flush again? I imagine i should not leave the solvent in indefinitely, right?

I have had the car about 3 years and have not put too many miles on it, but the PO said he did a spill and fill on the trans every oil change or so. That may be the reason that this still has life after 230K miles. Ashamedly, I have not been as diligent about it.

(BTW, I only say Gibbons-ish because I was a quart or so short on the new fluid, so I stopped just short of a full flush).
thanks!