Pinpoint Test B: DTC C1724 - Air Suspension Height Sensor Power Circuit Failure

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Vehicle Dynamic Suspension for schematic and connector information.

Normal Operation 

The vehicle dynamics module (VDM) sends power to the height sensor along circuit 417 (VT/OG) and the voltage returns along circuit 432 (BK/PK). The sensor sends the position signal back to the VDM along circuit 427 (PK/BK).

• DTC C1724 Air Suspension Height Sensor Power Circuit Failure - This DTC can be set during normal operation and during the VDM on-demand self test. DTC C1724 will set during normal operation if the ignition key is in the RUN position and the height sensor supply voltage is not at the expected level for more than 2 minutes. DTC C1724 will set during the on-demand self test if the height sensor voltage is not detected after being enabled during the test.

This pinpoint test is intended to diagnose the following:

• Wiring, terminals or connectors
• Air suspension height sensor
• VDM

PINPOINT TEST B: DTC C1724 - AIR SUSPENSION HEIGHT SENSOR POWER CIRCUIT FAILURE 

1. B1 CHECK CIRCUIT 417 (VT/OG) FOR A SHORT TO VOLTAGE 
   • Disconnect: VDM C2131b
   • Disconnect: Air Suspension Height Sensor C4043
   • Turn the air suspension switch to the OFF position.
   • Key in ON position.
   Fig 1: Checking Circuit For Voltage
   Courtesy of FORD MOTOR CO.
   • Measure the voltage between air suspension height sensor C4043-3, circuit 417 (VT/OG), harness side and ground.
   • Is any voltage present? 
   1. YES  : REPAIR circuit 417 (VT/OG). CLEAR the DTC. REPEAT the self-test.
   2. NO  : Go to  B2.
2. B2 CHECK CIRCUIT 417 (VT/OG) FOR A SHORT TO GROUND 
   • Key in OFF position.
   Fig 2: Checking Circuit For Short To Ground
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between air suspension height sensor C4043-3, circuit 417 (VT/OG), harness side and ground.
   • Is the resistance greater than 10,000 ohms? 
   1. YES  : Go to  B3.
   2. NO  : REPAIR circuit 417 (VT/OG). CLEAR the DTC. REPEAT the self-test.
3. B3 CHECK CIRCUIT 417 (VT/OG) FOR AN OPEN 
   Fig 3: Checking Circuit For Open
   Courtesy of FORD MOTOR CO.
   • Measure the resistance between VDM C2131b-4, circuit 417 (VT/OG), harness side and air suspension height sensor C4043-3, circuit 417 (VT/OG), harness side.
   • Is the resistance greater than 5 ohms? 
   1. YES  : REPAIR circuit 417 (VT/OG). CLEAR the DTC. REPEAT the self-test.
   2. NO  : Go to  B4.
4. B4 CHECK THE VDM OUTPUT 
   • Connect: VDM C2131b
   • Key in ON position.
   • Turn the air suspension switch to the ON position.
   Fig 4: Checking Circuit For Voltage
   Courtesy of FORD MOTOR CO.
   • Measure the voltage between air suspension height sensor C4043-3, circuit 417 (VT/OG), harness side and ground.
   • Is the voltage approximately 5 volts? 
   1. YES  : INSTALL a new air suspension height sensor. REFER to Suspension Height Sensor . CLEAR the DTC. REPEAT the self-test.
   2. NO  : INSTALL a new VDM. REFER to Vehicle Dynamics Module (VDM) . CLEAR the DTC. REPEAT the self-test.