Pinpoint Test B: The Audio Control Module (ACM) Does Not Respond To The Diagnostic Tool
WARNING: This page is about a different car, the 2005 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
- 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?
- Yes : GO to B2.
- No : REPAIR the ACM C290b as necessary. CARRY OUT the diagnostic tool data link test.
- B2 CHECK CIRCUITS 914 (TN/OG) AND 915 (PK/LB) FOR AN OPEN BETWEEN THE DATA LINK CONNECTOR (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.
- 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.
- Are the resistances less than 5 ohms?
- Yes : GO to B3.
- No : REPAIR the circuit in question. CARRY OUT the diagnostic tool data link test.
- 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?
- Yes : INSTALL a new ACM. Refer to AUDIO UNIT . 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. CARRY OUT the diagnostic tool data link test.