Pinpoint Test G: THE AUDIO CONTROL MODULE (ACM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

G1 CHECK THE ACM C290C FOR DAMAGE
- Key in OFF position.
- Disconnect: ACM C290c.
- Inspect the ACM C290c for damage.
- Is the ACM C290c OK?
- Yes : GO to G2.
- No : REPAIR the ACM C290c as necessary. TEST the system for normal operation.
G2 CHECK FOR AN OPEN BETWEEN THE DATA LINK CONNECTOR (DLC) C251 AND THE ACM
- Measure the resistance between the ACM C290c-1, circuit 4-EG10 (GY/BK), harness side and the DLC C251-2, circuit 4-EG7 (GY/RD), harness side.
  
  Fig 1: Measuring The Resistance Between The ACM C290c-1, Circuit 4-EG10 (GY/BK), Harness Side And The DLC C251-2, Circuit 4-EG7 (GY/RD)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the ACM C290c-4, circuit 5-EG10 (BU/YE), harness side and the DLC C251-10, circuit 5-EG7 (BU/RD), harness side.
  
  Fig 2: Measuring The Resistance Between The ACM C290c-4, Circuit 5-EG10 (BU/YE), Harness Side And The DLC C251-10, Circuit 5-EG7 (BU/RD)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : GO to G5.
- No : GO to G3.
G3 CHECK FOR AN OPEN BETWEEN THE ACM AND JOINT CONNECTOR NO. 4 C223
- Disconnect: Joint Connector No. 4 C223.
- Measure the resistance between the ACM C290c-1, circuit 4-EG10 (GY/BK), harness side and joint connector No. 4 C223-16, circuit 4-EG10 (GY/BK), harness side.
  
  Fig 3: Measuring The Resistance Between The ACM C290c-1, Circuit 4-EG10 (GY/BK), Harness Side And Joint Connector No. 4 C223-16, Circuit 4-EG10 (GY/BK)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the ACM C290c-4, circuit 5-EG10 (BU/YE), harness side and joint connector No. 4 C223-7, circuit 5-EG10 (BU/YE), harness side.
  
  Fig 4: Measuring The Resistance Between The ACM C290c-4, Circuit 5-EG10 (BU/YE), Harness Side And Joint Connector No. 4 C223-7, Circuit 5-EG10 (BU/YE)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : GO to G4.
- No : REPAIR the circuit in question. TEST the system for normal operation.
G4 CHECK JOINT CONNECTOR NO. 4 FOR AN OPEN
- Measure the resistance between joint connector No. 4 C223-14, component side and joint connector No. 4 C223-16, component side.
  
  Fig 5: Measuring The Resistance Between Joint Connector No. 4 C223-14, Component Side And Joint Connector No. 4 C223-16
  Courtesy of FORD MOTOR CO.
- Measure the resistance between joint connector No. 4 C223-7, component side and joint connector No. 4 C223-9, component side.
  
  Fig 6: Measuring The Resistance Between Joint Connector No. 4 C223-7, Component Side And Joint Connector No. 4 C223-9
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : REPAIR the circuit in question between the DLC C251 and joint connector No. 4 C223. CARRY OUT the diagnostic tool data link test.
- No : REPAIR joint connector No. 4 C223. TEST the system for normal operation.
G5 CHECK FOR CORRECT ACM OPERATION
- Disconnect all the ACM connectors.
- Check for:
- corrosion
- push-out pins
- Connect all the ACM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new ACM. REFER to AUDIO UNIT . TEST the system for normal operation.
  CARRY OUT the diagnostic tool data link test.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.