DTC P0551: Power Steering Switch Failure: Testing
- Turn ignition off. Disconnect power steering pressure switch 2-pin connector. See Figure . Turn ignition on. Using scan tool, monitor power steering pressure switch state. Connect one end of a jumper wire to sense circuit (Dark Blue/Light Green wire) at power steering pressure switch harness connector. Repeatedly touch other end of jumper wire to ground. If power steering pressure switch state did not change from HIGH to LOW, go to next step. If power steering pressure switch state changed from HIGH to LOW, replace power steering pressure switch.
- Turn ignition off. Connect a test light between battery positive and ground circuit (Black/Tan wire) at power steering pressure switch harness connector. If test light illuminates, go to next step. If test light does not illuminate, repair open in ground circuit.
- Disconnect PCM harness connector. PCM is located in engine compartment, between air cleaner and radiator. Measure resistance between ground and sense circuit (White wire) at power steering pressure switch harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in sense circuit.
- Measure resistance of sense circuit (White wire) between power steering pressure switch harness connector and terminal No. 45 at PCM C2 harness connector. See Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in sense circuit.
- If no other possible causes are remaining, replace PCM.