Pinpoint Test B: The Audio Control Module (ACM) Does Not Respond To The Diagnostic Tool

Test Step 

B1 CHECK THE ACM C290b FOR DAMAGE 

• Key in OFF position.
• Disconnect: ACM C290b.
• Inspect the ACM C290b for damage.
• Is the ACM C290b OK? 

Result / Action to Take 

Yes 

GO to B2.

No 

REPAIR the ACM C290b as necessary. CARRY OUT the diagnostic tool data link test.

Test Step 

B2 CHECK CIRCUITS 914 (TN/OG) AND 915 (PK/LB) FOR AN OPEN BETWEEN THE DLC C251 AND THE ACM C290b 

• Key in OFF position.
• Measure the resistance between the ACM C290b pin 9, circuit 914 (TN/OG), harness side and the DLC C251 pin 2, circuit 914 (TN/OG), harness side.
  Fig 1: Checking Circuit 914 (TN/OG) For An Open Between DLC C251 And ACM C290b

  Courtesy of FORD MOTOR CO.
• Measure the resistance between the ACM C290b pin 19, circuit 915 (PK/LB), harness side and the DLC C251 pin 10, circuit 915 (PK/LB), harness side.
  Fig 2: Checking Circuit 915 (PK/LB) For An Open Between DLC C251 And ACM C290b

  Courtesy of FORD MOTOR CO.
• Are the resistances less than 5 ohms? 

Result / Action to Take 

Yes 

GO to B3.

No 

REPAIR the circuit in question. CARRY OUT the diagnostic tool data link test.

Test Step 

B3 CHECK FOR CORRECT ACM OPERATION 

• Disconnect all the ACM connectors.
• Check for:
  • corrosion
  • pushed-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? 

Result / Action to Take 

Yes 

INSTALL a new ACM. REFER to ENTERTAINMENT SYSTEM - GENERAL INFORMATION . CARRY OUT the diagnostic tool data link test.

No 

The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.