Steering locks up mid turn, engine stalls

[BalticBro]

Hey all, I'm losing my mind (whatever's left of it anyway) trying to figure out this issue with my 2002 S60 2.3 T5.

The steering wheel is intermittently stiff, sometimes feeling like it completely locks up mid-turn and the engine stalls for a second at the same time . It only happens while driving and I cannot replicate it at a standstill. Steering is always light as a feather when the car is not moving.

I tried lubing the crap out of the steering u-joint, and that didn't do anything, plus it wouldn't cause the engine to stall anyway. Power steering fluid level is good and the fluid looks only slightly faded - more light brown than it is red.

I also checked the accessory drive in case something is seizing there, but there's nothing to write home about. The power steering pump felt fine, but I did replace the belt and got the alternator rebuilt since it had a few problems.

There are no DTC stored and I'm stumped. I've noticed that turning the steering wheel at a standstill does affect the RPMs noticeably, and it gets pretty bad at full lock, so I ordered a new power steering pump which should arrive in a couple of days. Hopefully, that fixes it but I'm doubtful.

This death machine scares me to be honest. It's too dangerous to drive at this point.

Any ideas on what could be causing this?

[yanga001]

Few questions here.

Do you have the speed assisted rack or the non assisted rack? Do you have a code scanner that can check the racks?

I've had pumps go bad in other cars and it went from assist to no assist so it could be a completely worn pump. This was in an acura rdx and colour wise the fluid was a metallic sheen so that is different.

Just noticed you said red, pentosin is not red its blue if i recall. Do you have the incorrect fluid in the vehicle? I do not think it would make a huge difference in terms of performance, however the fluid may be more worn then expected.

Can you put the car on jack stands and see if you can replicate it with wheels in the air?

If we know its an electric rack then we need to explore how that system works, specifically will a failing rack cause loss of assist at speed.

If its a normal rack then check if the racks internals may be failing.

Sinc you already bought a pump, id say the next course of action is install the pump, bleed and flush the steering fluid, and see how it performs. If you still have issues then confirm what kind of rack you have and get back to us.

[BalticBro]

I checked whether it's speed-assisted yesterday and I didn't see any solenoid or electrical connector on the rack, just two hard lines going to it so I assume it's a basic non-assisted rack. Yes, I do have VIDA Dice so I'll double check just in case.

As for fluid, I used red ATF which I got from a Volvo truck dealership I used to work at. All the other guys used it as well on their S60 and V70 Volvos so I did the same. The car had red fluid when I bought it in 2019 too. Maybe I should switch to Pentosin?

Getting the wheels off the ground is a great idea, I'll try to do that too if I have time.

Thanks for the advice, I'll report back once I get the new pump. Not looking forward to the test drive tho lol.

[jonesg]

i've driven mine 50 miles with no power steering, it has no effect on ignition but if you have a big vac leak riding the brake in a turn can make it stumble.
but if the engine quit mid turn it would make the steering very heavy in the turn...watch the tach for stumbling.

it can also be the fuel pump,
is the tank below 1/4 full ?
does it happen more in one direction, left or right ?

you can monitor fuel pressure to diagnose while driving.

[cn90]

Could be:

- PS Pump
- Rack binding

[firstv70volvo]

Because you can't replicate the problem at a standstill I was trying to think of what's different when driving. Engine RPM for one thing which could potentially affect the PS pump pressure and operation so you might try increasing the engine RPMs while at a standstill and turning the steering wheel to see if you might be able to replicate the problem this way.
There's also different loading on the suspension when driving so if it were a mechanical problem with the suspension parts, such as the lower ball joints, struts or upper strut bearing mount than this could potentially cause mechanical binding under different loads. This seems like a long shot to me though.
There's also the steering rack spool valve and leaky seals that may respond to different pump pressures while driving and another reason to try the increase in RPM while standing still.
When you feel the steering lock up does it happen when you turn right or left or only one way? Does it happen at different places in the turn or always at the same place in the steering wheel position when it happens?
Typically, hard steering during turning is leaky internal seals in the steering rack but there isn't the stalling you mentioned.

[jonesg]

Because you can't replicate the problem at a standstill I was trying to think of what's different when driving. Engine RPM for one thing which could potentially affect the PS pump pressure and operation so you might try increasing the engine RPMs while at a standstill and turning the steering wheel to see if you might be able to replicate the problem this way.
There's also different loading on the suspension when driving so if it were a mechanical problem with the suspension parts, such as the lower ball joints, struts or upper strut bearing mount than this could potentially cause mechanical binding under different loads. This seems like a long shot to me though.
There's also the steering rack spool valve and leaky seals that may respond to different pump pressures while driving and another reason to try the increase in RPM while standing still.
When you feel the steering lock up does it happen when you turn right or left or only one way? Does it happen at different places in the turn or always at the same place in the steering wheel position when it happens?
Typically, hard steering during turning is leaky internal seals in the steering rack but there isn't the stalling you mentioned.

what is the connection between power steering and ignition.?

[firstv70volvo]

Because you can't replicate the problem at a standstill I was trying to think of what's different when driving. Engine RPM for one thing which could potentially affect the PS pump pressure and operation so you might try increasing the engine RPMs while at a standstill and turning the steering wheel to see if you might be able to replicate the problem this way.
There's also different loading on the suspension when driving so if it were a mechanical problem with the suspension parts, such as the lower ball joints, struts or upper strut bearing mount than this could potentially cause mechanical binding under different loads. This seems like a long shot to me though.
There's also the steering rack spool valve and leaky seals that may respond to different pump pressures while driving and another reason to try the increase in RPM while standing still.
When you feel the steering lock up does it happen when you turn right or left or only one way? Does it happen at different places in the turn or always at the same place in the steering wheel position when it happens?
Typically, hard steering during turning is leaky internal seals in the steering rack but there isn't the stalling you mentioned.

what is the connection between power steering and ignition.?

I'm assuming you're thinking the stalling is an ignition problem?
My take on the stalling mentioned, based on the description of the lock up, is that it's from an excessive load on the PS pump due to an actual mechanical binding problem or a problem with PS pump pressure getting too high for some reason. As always, I could be wrong about all of this.

[jonesg]

I'm assuming you're thinking the stalling is an ignition problem?
My take on the stalling mentioned, based on the description of the lock up, is that it's from an excessive load on the PS pump due to an actual mechanical binding problem or a problem with PS pump pressure getting too high for some reason. As always, I could be wrong about all of this.

agree..could be,
so one way to parse out the symptom is remove the acc belt.

[BalticBro]

Alright, so I had a bit of free time today, so I tried to recreate the problem again without getting on the busy road that my garage is right next to.

My gas tank is a little over half full, I tried driving around slow, faster, braking, multiple 3 point u-turns in both directions, etc. - no results, the car works perfectly. Then I parked outside in the sun and held the rpms at 2k to simulate driving, tried wiggling the wheel, tried fast turns, ac on, ac off, and just generally tortured the car and the steering for 15 minutes straight - absolutely no problem, the steering felt great and engine didn't even stumble.

So, to answer your questions guys, it originally happened during left turns for sure, but I remember that the engine stumbled once during a slower but tight right turn. I looked at the rack again and didn't see the solenoid. Also, Vida says I have a standard rack.

At this point, I'm questioning my own sanity. Maybe I get scared once the engine dies and I unknowingly push in the clutch, thus disabling power steering? Maybe it's primarily an issue of the engine stalling during turns, and the steering wheel "locking up" for a moment is just a symptom.

One thing I did figure out by removing the ACC belt is that something on the drive is likely bogging down the engine. With the belt on, if I quickly blip the throttle all the lights in the car dim and then go bright again, but once I remove the belt, the lights stay constant. I'm pretty sure that the alternator is not the issue since I had it fully tested and rebuilt this week - it had a bad freewheel and bearings. I spun the AC compressor pulley, clutch, tensioner pulley, and the power steering pump by hand and they all felt fine.

I'll pick up the power steering pump tomorrow and try it out, but I'm a bit skeptical. I'll try to check out the CEM connectors and try wiggling the wires with the engine on while I'm at it just in case it's a wiring issue. I'll try to do a test drive at a higher speed on the road tomorrow.

I'm just hoping that it's not the CEM that's going intermittently bad, because the car itself is probably not worth the money that the CEM replacement or repair would cost.