I was at the mall parking lot, late in the evening, on my way home back from the office, backing to a parking space, made some quick left and rights, as if there were no empty spaces to park… Oh no! “Service Four Wheel Steer”… Turned the engine off/on, seems OK. Went shopping, came back, turned on the engine “Service Four Wheel Steer”…, Turned off/on seems OK. Drove home, no problems, dropped bags, drove to my favourite school parking lot, made Os, 8s, Checked OK. Went home, parked…In the morning “Service Four Wheel Steer”. Off/on, nop, still “Service Four Wheel Steer”.

I thought it is the DTC C0455, BCM programming issue that is posted on the forum some time ago. Went to the nearest dealer to my office. Nop, there is something else; they find codes C0533 and C0543.

C0533 points to the rear steering motor control relay problems, C0543 is generated by the rear steering control module, when the actuator wont response to the control module command. They tested the circuit, verdict is to replace the rear steering motor; either the relay or the motor is gone.

I got the new motor today, tested the truck with the service advisor, everything seems OK.

DTC code description pages from CK8 service manual and the service job order with the rear steering motor part# are below. Yup, they even wash the truck, and yes, the truck is still under warranty at ~15,000 miles.

One caution note, service job order is Canadian. Rear steering motor part number may be a GM Canada part number. Sometimes GM assigns Canadian and US part numbers to the same part.

DTC C0533

DTC C0543

Any idea how much those motors are?

You probably don't want to know. $$$$$

Dealer did not give me the exact figure, but they said the motor is around $1000 Canadian + labour. It is an easy change, I would have done it myself, if the truck is out of warranty.

How many of you guys had to replace the steering motor and at what mileage did it fail? Thinking about buying parts now before they get hard to find and expensive. Since QS is obsolete. Also thinking about removing my QS and installing a regular Dana 60. Then I could put some really wide tires in the back.