C2008

Code

Generic C — Chassis

Chassis Control Module Communication Fault

Brand: Generic

Type: C — Chassis

Views: UK: 24 EN: 39 RU: 20

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Page language: EN

Causes

Open or shorted wiring between CCM and vehicle data bus
Poor or missing power or ground to the CCM
Faulty CCM or internal failure
Missing or damaged CAN termination or bus wiring
Intermittent connector contact or corrosion
Other module causing bus errors or overwhelming the CAN bus

Symptoms

Chassis/ABS/traction/stability functions disabled or limited
Dash warning lamps: ABS, Traction Control, Stability, or general Chassis warnings
Messages such as “Service Chassis System” or “Communication Fault”
Loss of some networked features or inability to communicate with the CCM using a scan tool
Intermittent or permanent driveability or braking system faults depending on system architecture

What to check

Read all stored and pending DTCs on all modules — note U- and C-codes and freeze-frame data
Attempt to communicate with CCM using scan tool; verify module presence and response
Check battery voltage (engine off and cranking) and inspect fuses/relays supplying CCM
Visually inspect CCM connector for corrosion, bent pins, contamination, or water intrusion
Inspect CAN bus wiring harness for physical damage, chafing, or repairs
Measure CAN bus termination resistance (~60 ohms between CAN_H and CAN_L at key connectors)

Signal parameters

CAN bus idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (recessive)
CAN dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (typical)
Differential voltage when dominant ≈ 2.0 V
Termination resistance: ~60 ohms between CAN_H and CAN_L (two 120 Ω resistors in parallel)
Module supply voltage: battery voltage ~11–14 V with ignition on
Ground continuity: chassis ground to module should be low resistance (

Diagnostic algorithm

Retrieve and record all DTCs, freeze-frame, and ECU responses from all modules. Note related U-codes or repeated network errors.
Attempt to communicate with the CCM using a known-good scan tool. Confirm whether the module responds, its serial number, and software version if available.
Verify battery voltage and charging system; inspect and test fuses/relays that supply CCM power. Repair any supply issues.
Visually inspect CCM connector and wiring. Disconnect connector and inspect pins for corrosion, bent pins, pushed-out terminals, or moisture. Re-seat connector.
Check ground integrity: measure voltage drop between CCM ground and chassis while cranking and under load; repair poor grounds.
Measure CAN_H and CAN_L at the CCM connector with a multimeter/oscilloscope. Confirm idle voltages (~2.5 V) and differential behavior when network active. Look for shorts to GND or B+.
Measure termination resistance across CAN_H and CAN_L near network ends (~60 Ω). If incorrect, inspect for missing termination or additional unintended terminations.
If the bus shows noise or errors, use an oscilloscope to capture frames and identify a noisy node. Disconnect suspect modules one at a time (if safe) to isolate the fault.
Repair or replace damaged wiring, connectors, or terminals. After repairs, clear codes and test-drive to confirm fault does not return.
If wiring and power/ground are good and the module still does not communicate, consider software update/reprogramming or replacement of the CCM and verify correct programming and configuration after replacement.