Slow Steering - 2015 Nissan Murano Long-Term Road Test
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Slow Steering - 2015 Nissan Murano Long-Term Road Test
Outrunning the power steering in the Edmunds long-term 2015 Nissan Murano.
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The first step would be to monitor scan data inputs to the steering module for the steering angle and torque sensor inputs, as well as the power output command from the steering module. Additional data pids could include module and/or motor temperature. That first look could present the first decision point as to whether this is possibly an input, output, or other issue.
The next step would be to directly measure the current draw of the motor. If the amperage that the motor is drawing is low, then testing would need to confirm good power and ground connections to the module as well as between the module and the motor. If it is high, then a mechanical issue of some type would need to be ruled out. Typical motor current will be fifteen amps or less for situations requiring little assist, and can exceed fifty amps of current when a lot of assist is required such as parking lot maneuvers or as in the above scenario.
Many manufacturers build in some type of thermal overload protection in their steering systems. If the temperature of the motor or module get's too high, then the module will reduce the current available to the motor, which results in a reduction of assist. It's quite likely that is what is going on here. Thermal events can often log historical data but they don't have to generate a "trouble code" because it can be considered as a normal occurrence.
As far as repairs go, sometimes software updates may be used to change the threshold level of thermal events, or maybe change the vehicle speed assist reduction table. (The faster you go the less assist you actually need)
It would be neat to see "normal" data from the module alongside data captured during a reduced assist event.