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Home >> Saturn >> 1995 >> SW2 Automatic >> Repair and Diagnosis (Single Page) >> Steering >> Power Steering >> Steering System - Variable Effort >> Testing >> System Test Procedures
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System Test Procedures

  1. Enter diagnostics using scan tester. Check for codes or Information Flag No. 16. See SELF-DIAGNOSTIC SYSTEM  . If Information Flag No. 16 is set, go to INFORMATION FLAG NO. 16 DIAGNOSIS  .
  2. If Powertrain Control Module (PCM) Code 24 or PCM Code 41 is set, diagnose and repair problem in Vehicle Speed Sensor (VSS) circuit. See G - TESTS W/ CODES article in the ENGINE PERFORMANCE section.
    CAUTION: To prevent power steering pump damage during pump pressure testing, open valve on tester before starting engine. During testing, DO NOT  turn steering wheel unless specified in procedure.
  3. If no information flag or codes are set, disconnect high pressure line at power steering pump. Connect Power Steering System Tester (SA9134C) between power steering high pressure line and pump fitting. Set parking brake. Place transmission in Park (Neutral on manual transmission). Open valve on tester. Start engine. Allow power steering system to reach operating temperature (2-3 minutes). Ensure fluid level is correct. If necessary, bleed hydraulic system. See HYDRAULIC SYSTEM BLEEDING  under LUBRICATION.
  4. With engine idling, record power steering pressure and flow rate. If pressure is greater than 150 psi (10.5 kg/cm2 ), stop engine and check for restricted power steering hose.
  5. Partially close valve until pressure is 700 psi (49 kg/cm2 ). Record flow rate. If difference between this flow rate and that obtained in previous step is greater than one gallon (3.8L) per minute, replace power steering pump ring, rotor and vanes. Check for worn or damaged pressure plate and thrust plates. Replace components, as necessary, or entire pump assembly.
    CAUTION: Pump will be damaged if tester valve is held closed for more than 5 seconds.
  6. Completely close valve for a few seconds, and then open it. Do this 3 times, recording highest pressure obtained each time valve is closed. If readings are not within 50 psi (3.5 kg/cm2 ) of each other, replace flow control valve. See Figure . Ensure flow control valve moves freely in bore.
  7. With engine speed at 1600 RPM, record flow rate. If difference between this flow rate and that obtained in step 4) is less than one gallon (3.8L) per minute, go to next step. If difference between flow rates is greater than one gallon (3.8L) per minute, remove and clean flow control valve. DO NOT  disassemble valve. Ensure valve moves freely.
  8. Turn steering wheel from stop to stop, recording pressure and flow rate at each stop. DO NOT  hold steering wheel at stops for more than 5 seconds. If flow rate at either stop is less than one gallon (3.8L) per minute, go to next step. If flow rate at either stop is greater than one gallon (3.8L) per minute, steering gear is leaking internally. Replace steering gear. See STEERING GEAR - POWER article. Remove tester. Fill and bleed system. See HYDRAULIC SYSTEM BLEEDING  under LUBRICATION.
  9. Turn ignition off. Connect Tech 1 scan tester. Select EVO SUBSYSTEM from SPECIAL TEST menu. Open valve on tester. Start engine. Using Tech 1 scan tester, command Electronic Variable Orifice (EVO) actuator to provide FULL ASSIST. If flow rate is not 2.35-2.85 gallons (8.9-10.8L) per minute, replace EVO actuator on pump.
  10. If flow rate is 2.35-2.85 gallons (8.9-10.8L) per minute, command EVO actuator to select NO ASSIST using Tech 1 scan tester. If flow rate is not 0.4-0.9 gallon (1.5-3.4L) per minute, replace EVO actuator.
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