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Pinpoint Test A: DTC C1897 - Steering VAPS Circuit Loop Failure

WARNING: This page is about a different car, the 2009 Mercury Grand Marquis and 2009 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Power Steering Controls for schematic and connector information.

Normal Operation 

The vehicle dynamics module (VDM) sends voltage to the power steering valve solenoid along circuit 114 (LB/YE), the voltage passes through the solenoid and returns to the VDM along circuit 115 (LG/BK). The power steering valve solenoid then controls power steering assist by regulating the flow of power steering fluid in the power steering pump. Depending on the amount of returning voltage, the VDM will be able to detect if the solenoid is functioning correctly.

This pinpoint test is intended to diagnose the following:

PINPOINT TEST A: DTC C1897 - STEERING VAPS CIRCUIT LOOP FAILURE 

NOTE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
  1. A1 ISOLATE THE POWER STEERING VALVE SOLENOID 
      WARNING: Before servicing a vehicle equipped with a fire suppression system, depower the system by following the procedure in FIRE SUPPRESSION SYSTEM article. Failure to follow the instructions may result in serious personal injury.
      NOTE: If equipped, turn the air suspension service switch to the OFF position.
    • With the vehicle in NEUTRAL, position it on a hoist. Refer to JACKING & LIFTING article.
    • Disconnect: Power Steering Valve Solenoid C120
    • Measure the resistance between power steering valve solenoid pin-1 and pin-2 component side.
    • Is the resistance approximately 6.4 ohms? 
    1. YES  : Go to  A2.
    2. NO  : INSTALL a new steering gear. CLEAR the DTCs. REPEAT the self-test. If equipped with fire suppression system, go to  A6.
  2. A2 CHECK CIRCUITS 114 (LB/YE) AND 115 (LG/BK) FOR AN OPEN 
    • Disconnect: VDM C2131a
      • Fig 1: Checking Circuits For Open
      GF0014226Courtesy of FORD MOTOR CO.
    • Measure the resistance between:
      • VDM C2131a-2, circuit 114 (LB/YE), harness side and power steering valve solenoid C120-2, circuit 114 (LB/YE), harness side.
      • VDM C2131a-1, circuit 115 (LG/BK), harness side and power steering valve solenoid C120-1, circuit 115 (LG/BK), harness side.
    • Are the resistances less than 5 ohms? 
    1. YES  : Go to  A3.
    2. NO  : REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test. If equipped with fire suppression system, go to  A6.
  3. A3 CHECK CIRCUITS 114 (LB/YE) AND 115 (LG/BK) FOR A SHORT TO GROUND 
      Fig 2: Checking Circuits For Short To Ground
      GF0014227Courtesy of FORD MOTOR CO.
    • Measure the resistance between ground and:
      • power steering valve solenoid C120-2, circuit 114 (LB/YE), harness side.
      • power steering valve solenoid C120-1, circuit 115 (LG/BK), harness side.
    • Are the resistances greater than 10,000 ohms? 
    1. YES  : Go to  A4.
    2. NO  : REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test. If equipped with fire suppression system, go to  A6.
  4. A4 CHECK CIRCUITS 114 (LB/YE) AND 115 (LG/BK) FOR A SHORT TO VOLTAGE 
    • Key in ON position.
      • Fig 3: Checking Circuits For Short To Voltage
      GF0014228Courtesy of FORD MOTOR CO.
    • Measure the voltage between ground and:
      • power steering valve solenoid C120-2, circuit 114 (LB/YE), harness side.
      • power steering valve solenoid C120-1, circuit 115 (LG/BK), harness side.
    • Is any voltage present? 
    1. YES  : REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test. If equipped with fire suppression system, go to  A6.
    2. NO  : Go to  A5.
  5. A5 CHECK CIRCUITS 114 (LB/YE) AND 115 (LG/BK) FOR A SHORT TOGETHER 
    • Key in OFF position.
      • Fig 4: Checking Circuits For Shorted Together
      GF0014229Courtesy of FORD MOTOR CO.
    • Measure the resistance between power steering valve solenoid C120-1, circuit 115 (LG/BK), harness side and power steering valve solenoid C120-2, circuit 114 (LB/YE), harness side.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : INSTALL a new VDM. REFER to VEHICLE DYNAMIC SUSPENSION article. CLEAR the DTC. REPEAT the self-test. If equipped with fire suppression system, go to  A6.
    2. NO  : REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test. If equipped with fire suppression system, go to  A6.
  6. A6 REPOWER THE FIRE SUPPRESSION SYSTEM 
    NOTE: If equipped, turn the air suspension service switch to the ON position.
      WARNING: If the vehicle is equipped with a fire suppression system, repower the system. For important safety warnings and procedures, refer to FIRE SUPPRESSION SYSTEM article. Failure to follow these instructions may result in serious personal injury.
    • Verify that the fire suppression system is repowered. Refer to FIRE SUPPRESSION SYSTEM article.
    • Is the fire suppression system repowered? 
    1. YES  : Fire suppression system repowering is complete.
    2. NO  : REFER to FIRE SUPPRESSION SYSTEM article for fire suppression system depowering and repowering procedure.
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