C1D11 — Chassis Control Module — CAN Communication Fault with ABS/ESC

Causes

• Open, short or high resistance in CAN wiring between CCM and ABS/ESC module
• Corroded, loose or damaged connectors/pins at CCM, ABS or intermediate junctions
• Missing or faulty CAN termination resistor(s)
• Failed or intermittent ABS/ESC control module
• Failed or intermittent Chassis Control Module (CCM)
• Low battery voltage, poor power/ground to one of the modules

Symptoms

• ABS and/or ESC warning lamp(s) on the dash
• Loss or reduction of ABS/traction/stability control functionality
• No ABS/ESC data available in the diagnostic tool for the expected module
• Intermittent faults or communication dropouts while driving
• Possible other network errors or unrelated modules showing communication faults

What to check

• Read stored and pending DTCs on all modules; record freeze-frame / timestamps
• Check and record battery voltage with ignition on and cranking
• Visually inspect CCM and ABS connectors for corrosion, bent pins, water ingress
• Scan for CAN-bus activity (bus load, presence of both nodes) using scan tool or oscilloscope
• Measure CAN-H and CAN-L voltages with key on (approx. 2.5 V idle) and observe differential during activity
• Measure resistance across CAN-H to CAN-L with ignition off (≈60 ohms for a properly terminated bus)

Signal parameters

• CAN High (idle): ≈2.5 V; dominant state ≈3.5 V (approx.)
• CAN Low (idle): ≈2.5 V; dominant state ≈1.5 V (approx.)
• CAN differential (dominant): ≈2.0 V
• Bus termination: two 120 Ω resistors in parallel → ≈60 Ω measured across CAN_H and CAN_L (ignition off)
• Expected continuous CAN traffic from ABS/ESC when ignition on — messages/sec depends on model but bus should show activity

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