LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2023 >> Compass Altitude >> Repair and Diagnosis >> Engine Performance >> System >> 2.0L - DTCS U0109 To U0427 >> DTC Troubleshooting >> U012D-Lost Communication With Alternator Control Module >> Possible Causes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Possible Causes

Possible Causes
LIN BUS CIRCUIT OPEN OR SHORTED
FUSED B+ CIRCUIT OPEN
POOR GROUND THROUGH ALTERNATOR CASE
ALTERNATOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. Refer to  PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE  .