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Jeep
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2010
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Commander Limited, 4WD
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Repair and Diagnosis
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Engine Performance
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Engine Control Systems
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Front Control Module (FCM) - Electrical Diagnostics
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DTC Troubleshooting
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U0121-Lost Communication With Anti-Lock Brake Module
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Possible Causes
Possible Causes
Possible Causes
CAN B OR CAN C BUS CIRCUITS OPEN OR SHORTED
DTCS RELATED TO BATTERY VOLTAGE, IGNITION, OR VIN MESSAGES
FCM NOT CONFIGURED CORRECTLY
ANTILOCK BRAKE MODULE POWER AND GROUND
ANTILOCK BRAKE MODULE
MODULE THAT SET THIS DTC