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Home >> Mercury >> 2009 >> Mariner Base, 2.5 7, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 139 (Electronic Suspension - Vehicle Dynamic Suspension System) >> Diagnostic Tests >> Vehicle Dynamic Suspension >> Pinpoint Tests >> Pinpoint Test E: DTC C1770 - Air Suspension Vent Solenoid Output Circuit Failure

Pinpoint Test E: DTC C1770 - Air Suspension Vent Solenoid Output Circuit 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, Vehicle Dynamic Suspension for schematic and connector information.

Normal Operation 

When venting of the rear air suspension system is necessary, the vehicle dynamics module (VDM) sends voltage to the vent solenoid along circuit 421 (PK). This voltage engages the solenoid which then vents the system. The solenoid is provided a ground along circuit 57 (BK). The vent solenoid is part of the air suspension compressor assembly and is serviced as such.

This pinpoint test is intended to diagnose the following:

PINPOINT TEST E: DTC C1770 - AIR SUSPENSION VENT SOLENOID OUTPUT CIRCUIT 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. E1 CHECK CIRCUIT 57 (BK) FOR AN OPEN 
      Fig 1: Checking Circuit For Open
      GF0013871Courtesy of FORD MOTOR CO.
    • Measure the resistance between the air compressor C1179-3, circuit 57 (BK), harness side and ground.
    • Is the resistance greater than 5 ohms? 
    1. YES  : REPAIR circuit 57 (BK). CLEAR the DTC. REPEAT the self-test.
    2. NO  : Go to  E2.
  2. E2 CHECK CIRCUIT 421 (PK) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: VDM C2131a
    • Disconnect: Air Compressor C1179
    • Key in ON position.
      • Fig 2: Checking Circuit For Short To Voltage
      GF0013868Courtesy of FORD MOTOR CO.
    • Measure the voltage between the air compressor C1179-4, circuit 421 (PK), harness side and ground.
    • Is any voltage present? 
    1. YES  : REPAIR circuit 421 (PK). CLEAR the DTC. REPEAT the self-test.
    2. NO  : Go to  E3.
  3. E3 CHECK CIRCUIT 421 (PK) FOR A SHORT TO GROUND  
    • Key in OFF position.
      • Fig 3: Checking Circuit For Short To Ground
      GF0013869Courtesy of FORD MOTOR CO.
    • Measure the resistance between the air compressor C1179-4, circuit 421 (PK), harness side and ground.
    • Is the resistance greater than 10,000 ohms? 
    1. YES  : Go to  E4.
    2. NO  : REPAIR circuit 421 (PK). CLEAR the DTC. REPEAT the self-test.
  4. E4 CHECK CIRCUIT 421 (PK) FOR AN OPEN 
      Fig 4: Checking Circuit For Open
      GF0013870Courtesy of FORD MOTOR CO.
    • Measure the resistance between the VDM C2131a-7, circuit 421 (PK), harness side and air compressor C1179-4, circuit 421 (PK), harness side.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  E5.
    2. NO  : REPAIR circuit 421 (PK). CLEAR the DTC. REPEAT the self-test.
  5. E5 CHECK THE AIR COMPRESSOR VENT SOLENOID 
    • Measure the resistance between the air compressor connector C1179-4, component side, and connector C1179-3, component side.
    • Is the resistance between 30 and 35 ohms? 
    1. YES  : INSTALL a new VDM. REFER to Vehicle Dynamics Module (VDM) . CLEAR the DTC(s). REPEAT the self-test.
    2. NO  : INSTALL a new air compressor. REFER to Air Suspension Compressor . CLEAR the DTC. REPEAT the self-test.
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