Heavy Steering at low speed?

2007 MERCEDES BENZ CLK230
202,000 MILES • 2.0L • 4 CYL • TURBO • 2WD • AUTOMATIC
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KEN_SCAN_1769885884
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Hi!

I have an issue with power steering. Even if i changed the power steering pump with a new one, steering is still very heavy at low speed. Also, steering fluid was changed and flushed.

I don't have any other errors on the car display or on the OBD scanner. Before, i had an error on the right side for the ABS sensor, but i changed it.

Any ideea of what can be the issue?

Thanks,
Robert
Nov 4, 2025 at 11:37 PM
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KRAKENAUTO
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Has the rack and pinion been inspected for any leaks, seal issues or failure? What you are describing does point to a bad rack and pinion. Failure can be caused by the power steering pump.
Nov 5, 2025 at 10:12 AM
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KEN_SCAN_1769885884
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thanks a lot for you answer! Power steering pump is a new one, just changed it.

Also, on the rack side, it was rebuild and everything looks ok from this point.

Any ideea? can be something electrical? from a sensor or something?
Nov 7, 2025 at 2:21 AM
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KRAKENAUTO
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Ok. Let me do some more research.
Nov 7, 2025 at 5:34 AM
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KRAKENAUTO
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I just want reach out to you. Mercedes has an electronic setup that controls the amount of power steering assistance based on vehicle speed. I will look through the schematics and see which sensors/etc to further guide you where to look once I determine which controls what.
Nov 9, 2025 at 6:41 AM
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KEN_SCAN_1769885884
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that will be great because i don't know what else should i check. Thanks a lot!
Nov 10, 2025 at 2:27 AM
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STRAILER
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KRAKENAUTO is one of our best! Please let us know how it goes :)
Nov 10, 2025 at 9:14 AM
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KRAKENAUTO
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Can you confirm the year/make and model as I don't see a clk230 with a 2.0 engine listed for 2007.
Nov 11, 2025 at 8:51 AM
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KEN_SCAN_1769885884
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aaa, no... is a CLK200 1.8 kompressor 2007, 135KW
Nov 11, 2025 at 9:00 AM
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KRAKENAUTO
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There is a Power Steering Solenoid Valve / Power Steering Control Valve (could be called either or).

This solenoid valve is essential for regulating the flow of power steering fluid to the steering rack and ensuring that your vehicle's steering operates smoothly and precisely.
Nov 11, 2025 at 9:24 AM
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KEN_SCAN_1769885884
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do you know the location? after i was reading on the internet i asked about this a mechanic but he told me that this model doesn't have it....
Nov 11, 2025 at 9:28 AM
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STRAILER
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That valve is inside the pump, can I ask if you have an electrical connector at the steering pump?
Nov 12, 2025 at 11:22 AM
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KEN_SCAN_1769885884
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No, I don't have an electrical connector.
Nov 13, 2025 at 2:21 AM
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STRAILER
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Okay, then you don't have a valve controlling the amount of power steering you get at different speeds like high end Mercedes. You changed out the pump with no change this just leaves the rack which needs to be replaced due to it being defective.
Nov 13, 2025 at 10:49 AM
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KEN_SCAN_1769885884
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that's the issue... I have also refurbished the rack.. and from my point of view is still to stiff(a little bit better... but not a lot). I also made a test with the new pump and is returning only 100Bar instead of 120 like it says on the paper. Do you think this can be an issue?
Nov 13, 2025 at 2:35 PM
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STRAILER
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Yep, that can make the difference, but can I ask if the engine was above idle when you did the test? If so the pump is no good, if not redo the test with the engine revved slightly.
Nov 15, 2025 at 8:59 AM
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KEN_SCAN_1769885884
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actually the test of the pump was not done on the car but on another bench they had. I couldn't find some tool to measure this directly on the car
Nov 18, 2025 at 3:57 AM
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STRAILER
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Okay, the pump sounds like it is defective, did the car have the same problem before and after the new steering pump? If so I would replace the steering rack. Sometimes when the pump goes bad it can spread metal throughout the steering system so all of it needs to be replaced.
Nov 18, 2025 at 10:29 AM