Pinpoint Test B: The Audio Control Module (ACM) Does Not Respond To The Diagnostic Tool
WARNING: This page is about a different car, the 2004 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
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.
- 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?
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.