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Home >> Mitsubishi >> 2001 >> Mirage ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0551: Power Steering Pressure (PSP) Sensor Circuit Range/Performance >> Diagnostic Procedure
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Diagnostic Procedure

  1. Start engine and let idle. Using scan tool, check data list item No. 27 (POWER STEERING PRESSURE SWITCH). Observe scan tool display when steering wheel is stopped and when steering wheel is being turned. With engine at idle, scan tool should display OFF when steering wheel is stopped and ON when steering wheel is being turned. If scan tool displays as specified, problem is intermittent. See INTERMITTENT DIAGNOSTIC TROUBLE CODES  .
  2. Disconnect PSP switch 1-pin connector (Yellow/Black wire). Located on power steering pump. Start engine and allow it to idle. Using DVOM, check continuity between ground and PSP switch terminal on power steering pump. Continuity should not exist. Turn steering wheel to stop. Continuity should exist. If continuity is as specified, go to next step. If continuity is not as specified, replace PSP switch. Go to step  5 .
  3. Disconnect PSP switch connector. Turn ignition on. Using DVOM, check voltage between ground and PSP switch connector terminal. If battery voltage does not exist, go to next step. If battery voltage exists, inspect PSP switch connector for damage, poor or loose connection and repair as necessary. If PSP switch is okay, recheck for DTCs. If DTC P0551 resets, replace ECM. Go to step  5 .
  4. Check for loose or poor connections at PSP switch harness connector and ECM harness connectors B76 terminal No. 52 (A/T) or B39 terminal No. 37 (M/T) at ECM. Repair as necessary. If connections are okay, check for faulty circuit in Yellow/Black wire PSP switch harness connector A28 and ECM harness connector terminals B76 terminal No. 52 (A/T) or B39 terminal No. 37 (M/T). Repair circuit as necessary. If circuit is okay, replace ECM. Go to next step.
  5. Verify repair by driving vehicle according to other monitor drive cycle and check for DTCs. See OTHER MONITOR  under OBD-II DRIVE CYCLES under VERIFYING REPAIRS. Confirm DTC P0551 does not reset.
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