Variable steering stuck at max looseness. help!

[John Redcorn]

I'm just wondering if this might be the evo sensor everyone talks about, my problems not jerking steering like what most people are describing for evo sensor.

I left this morning and my steering is just very light even on the highway just a tiny touch will move the wheel a LOT and it sucks.

I was running late so I didn't have time to look but I guess on lunch I'll look at the wires to the evo sensor and wires to the orifice on the pump or gear wherever it is. Anything else I should be looking for?


Is there some kind of hack or resistor I could do in place of the evo sensor or something I could do to the orifice wiring to just make it max stiffness all the time?

 

[Redwood]

Go for the sensor replacement bro. Call the dealer for the part and have them bring it to you at work so you can change it tonight!

 

[John Redcorn]

I checked the wires, to the sensor anyway they are plugged in. I couldn't find any wires up front, I thought the actual valve is supposed to be on the pump or on the gear somewhere, didn't see anything.

I did find this:
http://www.justanswer.com/questions/m04x-97-k2500-7-4-suburban-electronic

and it tells you a way to test:

1. Disconnect the 3 wire connector from the steering wheel speed sensor.
2. With the key in the OFF position, use a digital multimeter (DMM) to test for resistance between CKT 1057 (ORN/BLK) and CKT 1059 (LT BLU).
3. Rotate the steering wheel slowly from lock to lock.
4. Record the highest reading. If the reading is above 12K ohms, replace the steering wheel speed sensor and bearing assembly. If the reading is below 12K ohms, the steering wheel speed sensor is operating as designed.

I'm going to try this tonight. I wonder why it has to be off? I don't even have big tires but I doubt I can turn them lock to lock with it off unless I jack the front end up.

 

[John Redcorn]

Well I guess my sensor is bad, it spiked up to 17k ohms a few times while I was turning the wheel.

Stupid me didn't check to see where I could buy one though until all the dealers are closed. I read oreillys was supposed to have it, I called and they have to order it. I guess I'm waiting until the morning for the dealer parts counter to open. (napa, autozone and advance auto have no idea what I'm talking about)

 

[718frankb]

just thinking out loud here - i hate how loose my steering is if i disconected the evo and put a resistor of say 5 ohms between CKT 1057 (ORN/BLK) and CKT 1059 (LT BLU) wouldnt that trick the pump to act slower thus tighten steering ? sorry for the thread jack

 

[John Redcorn]

just thinking out loud here - i hate how loose my steering is if i disconected the evo and put a resistor of say 5 ohms between CKT 1057 (ORN/BLK) and CKT 1059 (LT BLU) wouldnt that trick the pump to act slower thus tighten steering ? sorry for the thread jack

I'm thinking about experimenting with exactly this tomorrow before I try replacing the sensor.

Where did you get the 5 ohm value from? I know I saw a webpage earlier today at work that showed some values of what it should be at what steering angle but now I can't find it. all I know is above 12k = bad according to that link I have up there. I want to try several different value resistors and see whats best.

but what I'm wondering is, since variable effort steering is supposed to be based on speed do the wheel speed sensors have more input to how big or small the orifice gets opened than the steering angle sensor / column position sensor / electronic variable orifice sensor (I've seen it called 3 things today)

And another thought I had is, what if my evo sensor was bad all along and what I thought was the tahoes version of firm steering might have been actually been soft because of a bad evo and it just got lots softer for me today randomly. what if i I replace the sensor and it feels awesome? have you ever replaced yours? so many questions!

 

[John Redcorn]

I didn't end up experimenting with resistors and don't think I will now.

I woke up late this morning and only had until noon to go to the chevy dealer to get the sensor, didn't leave me enough time to try resistors and still buy the sensor if I couldn't find a good ohm-value one to use so I bought the sensor and it is amazing!

Mine must have been bad all along and just got a whole lot worse yesterday when it went to constant full assist because my steering now feels completely awesome compared to how it ever has since I got the tahoe in november.

It's a whole lot stiffer even driving 25mph and on the highway its a night and day difference.

Since I got my tahoe I replaced all ball joints, all steering linkage, all shocks, did alignment and this evo sensor is dollar for dollar the best most noticeable drivability improving thing I've done. also it only takes like 20 minutes.

And you can feel it loosen up the steering wheel when you get below 10mph or so just like its supposed to to help you getting into parking spots or manuevering trailers.

Anybody who's never replaced it even if you don't know you have a problem, I highly recommend getting out your multimeter (and maybe a kid to help you reach the wires!) and testing it.





I played around with the old sensor some more now that its out and now I see why I had to always hold my steering wheel with both hands. The sensor would just randomly spike up to high ~17k ohms in all sorts of spots in its travel. The controller for the variable effort steering sees anything above 12kohm as the sensor not being there and defaults into full assist mode.

I guess with it doing that, (before it went to constant full assist yesterday) hitting a tiny bump in the road could cause a chain reaction, bump moves the steering wheel a bit, movement causes sensor to spike to 17kohm, that opens up the orifice for full asisst mode for a flash, your hands aren't ready to keep a real light steering wheel straight and you move the wheel, you cause it to hit another resistance spike spot in the sensor, full assist again blah blah blah, you get it, it made it wander all over the highway. Now I can lightly hold on with one hand and it's fine and stiff.