Pinpoint Test A: The Compass Is Inoperative

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Always set the zone and calibrate the compass before replacing an inaccurate compass module.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to BATTERY, MOUNTING & CABLES -- FUSION, MILAN & MKZ article.

A1 CHECK THE AUTO-DIMMING INTERIOR MIRROR VOLTAGE SUPPLY
- Ignition OFF.
- Disconnect: Auto-Dimming Interior Mirror C911 or C9039 (Camera Display Mirror).
- Ignition ON.
- If not equipped with a camera display mirror, measure the voltage between the auto-dimming interior mirror C911-1, circuit CBP41 (BU), harness side and ground.
  
  Fig 1: Measuring Voltage Between Auto-Dimming Interior Mirror C911-1, Circuit CBP41 (BU) And Ground
  Courtesy of FORD MOTOR CO.
- If equipped with a camera display mirror, measure the voltage between the auto-dimming interior mirror C9039-1, circuit CBP41 (BU), harness side and ground.
  
  Fig 2: Measuring Voltage Between Auto-Dimming Interior Mirror C9039-1, Circuit CBP41 (BU) And Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to A2 .
- No : VERIFY the BCM fuse 41 (15A). If OK, REPAIR circuit CBP41 (BU) for an open. TEST the system for normal operation. If not OK, REFER to the SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
A2 CHECK THE COMPASS MODULE GROUND CIRCUIT FOR AN OPEN
- If not equipped with a camera display mirror, measure the voltage between the auto-dimming interior mirror C911-1, circuit CBP41 (BU), harness side and auto-dimming interior mirror C911-3, circuit GD139 (BK/YE), harness side and ground.
  
  Fig 3: Measuring Voltage Between Auto-Dimming Interior Mirror C911-1, Circuit CBP41 (BU) And C911-3, Circuit GD139 (BK/YE) And Ground
  Courtesy of FORD MOTOR CO.
- If equipped with a camera display mirror, measure the voltage between the auto-dimming interior mirror C9039-1, circuit CBP41 (BU), harness side and auto-dimming interior mirror C9039-3, circuit GD139 (BK/YE), harness side and ground.
  
  Fig 4: Measuring Voltage Between Auto-Dimming Interior Mirror C9039-1, Circuit CBP41 (BU) And C9039-3, Circuit GD139 (BK/YE) And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to A3 .
- No : REPAIR circuit GD139 (BK/YE) for an open. CLEAR the DTCs. REPEAT the self-test.
A3 CHECK THE COMPASS COMMUNICATION CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: IPC C220.
- Ignition ON.
- If not equipped with a camera display mirror, Measure the voltage between the auto-dimming interior mirror C911-7, circuit VMC30 (BU/GY), harness side and ground; and between the auto-dimming interior mirror C911-6, circuit VMC31 (GY/BU), harness side and ground.
  
  Fig 5: Measuring Voltage Between Auto-Dimming Interior Mirror C911-7, Circuit VMC30 (BU/GY) And Ground
  Courtesy of FORD MOTOR CO.
- If equipped with a camera display mirror, measure the voltage between the auto-dimming interior mirror C9039-9, circuit VMC31 (GY/BU), harness side and ground; and between the auto-dimming interior mirror C9039-10, circuit VMC30 (BU/GY), harness side and ground.
  
  Fig 6: Measuring Voltage Between Auto-Dimming Interior Mirror C9039-9, Circuit VMC31 (GY/BU) And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes : REPAIR the circuit in question for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
- No : Except Hybrid, GO to A4 .
  For Hybrid, GO to A6.
A4 CHECK THE COMPASS COMMUNICATION PLUS (+) CIRCUIT FOR AN OPEN AND SHORT TO GROUND
- Ignition OFF.
- If not equipped with a camera display mirror, measure the resistance between the auto-dimming interior mirror C911-6, circuit VMC31 (GY/ BU), harness side and the IPC C220-24, circuit VMC31 (GY/BU), harness side; and between the auto-dimming interior mirror C911-6, circuit VMC31 (GY/BU), harness side and ground.
  
  Fig 7: Measuring Resistance Between Auto-Dimming Interior Mirror C911-6 And IPC C220-24, Circuit VMC31 (GY/BU)
  Courtesy of FORD MOTOR CO.
- If equipped with a camera display mirror, measure the resistance between the IPC C220-24, circuit VMC31 (GY/BU), harness side and the auto-dimming interior mirror C9039-9, VMC31 (GY/BU), harness side; and between the IPC C220-24, circuit VMC31 (GY/BU), harness side and ground.
  
  Fig 8: Measuring Resistance Between IPC C220-24 And Auto-Dimming Interior Mirror C9039-9, VMC31 (GY/BU)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms between the IPC and the auto-dimming interior mirror, and greater than 10,000 ohms between the IPC and ground?
- Yes : GO to A5 .
- No : REPAIR the circuit for an open or short to ground. CLEAR the DTCs. REPEAT the self-test.
A5 CHECK THE COMPASS COMMUNICATION MINUS (-) CIRCUIT FOR AN OPEN AND SHORT TO GROUND
- Ignition OFF.
- If not equipped with a camera display mirror, measure the resistance between the auto-dimming interior mirror C911-7, circuit VMC30 (BU/ GY), harness side and the IPC C220-23, circuit VMC30 (BU/GY), harness side; and between the auto-dimming interior mirror C911-7, circuit VMC30 (BU/GY), harness side and ground.
  
  Fig 9: Measuring Resistance Between Auto-Dimming Interior Mirror C911-7 And IPC C220-23, Circuit VMC30 (BU/GY)
  Courtesy of FORD MOTOR CO.
- If equipped with a camera display mirror, measure the resistance between the IPC C220-23, circuit VMC30 (BU/GY), harness side and the auto-dimming interior mirror C9039-10, circuit VMC30 (BU/GY), harness side; and between the IPC C220-23, circuit VMC30 (BU/GY), harness side and ground.
  
  Fig 10: Measuring Resistance Between IPC C220-23 And Auto-Dimming Interior Mirror C9039-10, Circuit VMC30 (BU/GY)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms between the IPC and the auto-dimming interior mirror, and greater than 10,000 ohms between the IPC and ground?
- Yes : GO to A8.
- No : REPAIR the circuit for an open or short to ground. CLEAR the DTCs. REPEAT the self-test.
A6 CHECK THE COMPASS COMMUNICATION PLUS (+) CIRCUIT FOR AN OPEN AND SHORT TO GROUND (HYBRID)
- Ignition OFF.
- If not equipped with a camera display mirror, measure the resistance between the auto-dimming interior mirror C911-6, circuit VMC31 (GY/ BU), harness side and the IPC C220-16, circuit VMC31 (GY/BU), harness side; and between the auto-dimming interior mirror C911-6, circuit VMC31 (GY/BU), harness side and ground.
  
  Fig 11: Measuring Resistance Between Auto-Dimming Interior Mirror C911-6 And IPC C220-16, Circuit VMC31 (GY/BU)
  Courtesy of FORD MOTOR CO.
- If equipped with a camera display mirror, measure the resistance between the IPC C220-16, circuit VMC31 (GY/BU), harness side and the auto-dimming interior mirror C9039-9, VMC31 (GY/BU), harness side; and between the IPC C220-16, circuit VMC31 (GY/BU), harness side and ground.
  
  Fig 12: Measuring Resistance Between IPC C220-16 And Auto-Dimming Interior Mirror C9039-9, VMC31 (GY/BU)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms between the IPC and the auto-dimming interior mirror, and greater than 10,000 ohms between the IPC and ground?
- Yes : GO to A7 .
- No : REPAIR the circuit for an open or short to ground. CLEAR the DTCs. REPEAT the self-test.
A7 CHECK THE COMPASS COMMUNICATION MINUS (-) CIRCUIT FOR AN OPEN AND SHORT TO GROUND (HYBRID)
- Ignition OFF.
- If not equipped with a camera display mirror, measure the resistance between the auto-dimming interior mirror C911-7, circuit VMC30 (BU/ GY), harness side and the IPC C220-17, circuit VMC30 (BU/GY), harness side; and between the auto-dimming interior mirror C911-7, circuit VMC30 (BU/GY), harness side and ground.
  
  Fig 13: Measuring Resistance Between Auto-Dimming Interior Mirror C911-7 And IPC C220-17, Circuit VMC30 (BU/GY)
  Courtesy of FORD MOTOR CO.
- If equipped with a camera display mirror, measure the resistance between the IPC C220-17, circuit VMC30 (BU/GY), harness side and the auto-dimming interior mirror C9039-10, VMC30 (BU/GY), harness side; and between the IPC C220-17, circuit VMC30 (BU/GY), harness side and ground.
  
  Fig 14: Measuring Resistance Between IPC C220-17 And Auto-Dimming Interior Mirror C9039-10, VMC30 (BU/GY)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms between the IPC and the auto-dimming interior mirror, and greater than 10,000 ohms between the IPC and ground?
- Yes : GO to A8 .
- No : REPAIR the circuit for an open or short to ground. CLEAR the DTCs. REPEAT the self-test.
A8 CHECK FOR CORRECT IPC OPERATION
- Disconnect the IPC connector.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect the IPC connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new IPC. REFER to INSTRUMENTATION, MESSAGE CENTER & WARNING CHIMES -- FUSION, MILAN & MKZ article. TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.