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Home >> Mercury >> 2008 >> Sable Base, AWD >> Repair and Diagnosis (Single Page) >> Steering >> Power Steering >> Steering System - General Information >> Diagnostic Tests >> Steering System >> Pinpoint Tests >> Pinpoint Test D: Steering Has Lack of Assist or Inconsistent Assist >> Pinpoint Test D: Steering Has Lack Of Assist Or Inconsistent Assist

Pinpoint Test D: Steering Has Lack Of Assist Or Inconsistent Assist

  1. D1 CHECK FOR STEERING EFFORT CONTROL MODULE (SECM) DTCs 
    • Connect the diagnostic tool.
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Self Test SECM
    • Retrieve and record any SECM DTCs.
    • Are any SECM DTCs present? 
    1. YES  : REFER to the STEERING EFFORT CONTROL MODULE (SECM) DTC TABLE .
    2. NO  : Go to  D2.
  2. D2 CHECK THE STEERING RATE SIGNAL (STRSIGU) PID 
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger SECM
    • Start the engine and monitor the STRSIGU PID while turning the steering wheel right to left.
    • Does the PID change as the steering wheel is turned? 
    1. YES  : Go to  D3.
    2. NO  : INSTALL a new steering wheel rotation sensor. REFER to VEHICLE DYNAMIC SYSTEMS article. TEST the system for normal operation.
  3. D3 CHECK THE STEERING ASSIST WITH THE ENGINE RPM RAISED 
      CAUTION: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
    • Set the engine at 2,100 RPM and turn the steering wheel fully to the left and right.
    • Is steering assist normal with the engine RPM raised? 
    1. YES  : INSTALL a new power steering pump. REFER to POWER STEERING article.
    2. NO  : Go to  D4.
  4. D4 CHECK FOR A CHANGE OF ASSIST ON LEFT AND RIGHT TURNS 
    • With the engine at idle, turn the steering wheel fully to the left and to the right.
    • Does the steering assist change when turning from right to left? 
    1. YES  : INSTALL a new steering gear. REFER to POWER STEERING article.
    2. NO  : Go to  D5.
  5. D5 CHECK THE STEERING LINES AND HOSES FOR RESTRICTIONS 
    • Inspect the steering lines and hoses for damage, kinks or restrictions.
    • Are the steering lines or hoses damaged, kinked or restricted? 
    1. YES  : INSTALL new lines or hoses as necessary. REFER to POWER STEERING article.
    2. NO  : Go to  D6.
  6. D6 MONITOR THE ENGINE RPM CHANGES 
    CAUTION: Do not hold the steering wheel at the stops for an extended amount of time. Damage to the power steering pump may occur.
    NOTE: Make sure that the vehicle is on a flat, dry surface, all accessories are in the OFF position and that the steering system is at normal operating temperature.
    • Connect the diagnostic tool.
    • Start the engine.
    • With the engine at idle, raise the power steering fluid temperature to 74-80°C (165-176°F) by rotating the steering wheel fully to the left and right several times.
    • While monitoring the engine RPM with the scan tool, turn the steering wheel quickly to the left stop position and then to the right stop position.
    • Note the engine RPM during the turns.
    • Does the engine RPM change (even temporarily) more than 30 RPM when turning the steering wheel? 
    1. YES  : INSTALL a new steering gear. REFER to POWER STEERING article.
    2. NO  : INSTALL a new power steering pump. REFER to POWER STEERING article.