Tilt & Tele Inop, No Codes

Benjamin Diagnostician Connecticut Posted   Latest   Edited  
Delayed
Electrical
2003 Lexus LS430 4.3L (3UZ-FE) 5-spd (A650E)
Tilt & Telescopic Motors Inop

Followed RM to diagnose tilt & tele steering wheel inop. No DTC, even if Motors disconnected, which is odd. Data list shows manual switch activation Up/Dn/In/Out OK. Active Test no motion. Controller IG, ECUB, B+ (14.2 V) & GND (2 ohms to body), OK. Momentary 128 VAC (Spec 190-230 VAC) on each of the actuator circuits backprobing the controller and the motors, OK.

One step of the RM confuses me when it says check sensor power source circuit, where I got 4.7 V on both, (4.8 V if I disconnect the motor) which is “OK” but RM says "Check for open circuit in harness and connector between terminals S5V1 and SG1, S5V2 and SG2 of ECU connector"? If this is “OK” then why am I checking for an open circuit?

I got a JYD controller but that didn't make a difference, and I'm thinking what are the chances both motors burning out at the same time? I don't have any motors or like vehicles around to test, either. I'm missing something. Thanks for your help.

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Dmitriy Analyst
Ontario
Dmitriy
 

Benjamin, you have not mentioned IG on the controller — what is its status with ignition on and off?

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Benjamin Diagnostician
Connecticut
Benjamin
 

I'll recheck in the morning.

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Benjamin Diagnostician
Connecticut
Benjamin
 

IG is 0.0 V IG-OFF and 14.2 V RUN.

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Randall Technician
Pennsylvania
Randall
 

Benjamin, I don’t have the answer, but I am intrigued as to why they used AC current motors? My understanding of AC motor starting is that a capacitor or start switch is needed, especially for high torque and reversing in single pole applications. If capacitors are used inside the motor, you might not be readily able to prove out the motors. good luck Randy

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Benjamin Diagnostician
Connecticut
Benjamin
 

I guess AC for speed control? Not sure where the caps are, but I'd guess in the controller. Not that it makes a difference, I really have no way to test them independently of the controller.

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Grant Technician
Illinois
Grant
   

The automatic tilt/telescopic feature of the motors can be disabled with a customize settings change. Not sure which ECU retains this specific setting. Have you checked for presence of the metal "clip" that completes a ground path? See the part labeled "bracket spacer" in my attachment. It completes a ground path between the metal “telescopic steering slider” and the metal “column tube". The…

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Benjamin Diagnostician
Connecticut
Benjamin
 

Ground was a good idea. Found steering column not grounded. I never thought to check to see if the horn works, but it doesn't work unless I jump the column to ground. So, I added a jumper from the column to the body to fix the horn. Still, since these are AC motors, fixing the ground didn't seem to make a difference.

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Eric Owner/Technician
Wisconsin
Eric
 

2 ohms seems like a lot of resistance on the ground circuit. I would perform a load test on that circuit, as well as the battery power supply circuits. I have used a light bulb (120 vac) in a socket with back probes to test the motor controls, a 40 watt bulb is what I've used in the past. Your 128 vac from the controller to the motor is too low, see what you get with the light bulb in place and…

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Benjamin Diagnostician
Connecticut
Benjamin
 

I'll have to go through the ground circuits, and I like the light bulb idea. I'll have to try it Monday.

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Benjamin Diagnostician
Connecticut
Benjamin Delay
 

All test results inconclusive, not going to pursue it further unless the customer can come up with a couple of motors. This is one of those, “They were working before you looked at it," jobs. Right, 18 years old and it's my fault? And why would I have touched it to confirm or deny it was working before? Just another headache.

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