P0551 Power steering switch malfunction
If you have a P0551 Power steering switch malfunction trouble code, read this article. The computer looks for the vehicle to be driven at least 40MPH for more than 30 seconds. The power steering switch is “normally closed,” meaning that the computer always sees voltage. If the computer see an OPEN on 2 or more trips, it sets this P0551 code.
The 40MPH figure is important. The whole purpose of the power steering pressure switch is to increase idle speed when the power steering pressure increases. That happens when the driver is doing parking maneuvers and the power steering pump is working harder to build enough pressure to move the wheels while the car is stationary. So, if the computer sees the open at higher speeds, that’s an indication of a problem with the switch, the harness, or the connector.
© 2012 Rick Muscoplat