Code
C2100
Generic
C — Chassis
Chassis Control Module Communication Fault
Views:
UK: 1
EN: 1
RU: 0
AI status
Completed
Completed
100%
Causes
- Damaged or chafed CAN/LIN wiring harness
- Poor or missing power supply or ground to the chassis control module
- Corroded, loose or bent module connector pins
- Missing/failed CAN bus termination resistor(s) or incorrect topology
- Faulty chassis control module (internal failure or software error)
- Blown fuse or relay supplying the module
Symptoms
- ABS, traction control or stability control warning lamps illuminated
- Loss or intermittent operation of ABS/ESC/traction functions
- Other network modules reporting communication errors or faults
- Stored and repeating communication DTCs related to chassis module
- Vehicle may enter limp or degraded handling modes
- No wheel speed or steering angle data shown in scan tool for chassis module
What to check
- Use a capable scan tool to read all stored codes and freeze frame data from all modules on the vehicle network
- Check battery voltage (with engine off and cranking) — low voltage can cause communication faults
- Inspect fuses/relays related to chassis control and vehicle communications
- Visually inspect harness and connectors for damage, corrosion or water intrusion at module and junction points
- With ignition on, check for module power and ground at the chassis control module connector
- Check for presence of CAN bus activity with a scan tool or bus diagnostic tool (bus node list, message stream)
Signal parameters
- CAN bus idle voltages: CANH ≈ 2.5 V, CANL ≈ 2.5 V
- Dominant state: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ≈ 2 V) on many networks
- Differential voltage: ~0 V when recessive, ~2 V when dominant
- Typical CAN bit rates: 125 kbps, 250 kbps or 500 kbps (verify vehicle-specific)
- Expected termination resistance: approx. 60 ohms between CANH and CANL (two 120 Ω terminations in parallel)
- Module supply voltage: battery voltage nominal (12.0–14.5 V depending on engine running/charging)
Diagnostic algorithm
- Read and record all DTCs from all controllers; note any U-codes or other module communication faults.
- Clear codes and attempt to re-scan to see whether C2100 returns and under what conditions (cold start, driving, turning steering, etc.).
- Verify battery condition and measure voltages at vehicle battery and at chassis control module power pin(s). Recharge or replace battery if low.
- Check related fuses/relays for continuity and correct operation; replace if faulty.
- Visually inspect wiring and connectors at the chassis control module and along the CAN network for damage, corrosion or loose pins; repair damaged insulation and connectors.
- Verify module ground(s) have low resistance to chassis (use backprobe):
- With ignition on, measure DC voltages on CANH and CANL at the module connector — expect ~2.5 V each. If voltages are out of range, trace power/termination and wiring.
- Use an oscilloscope or CAN bus analyzer to examine waveforms and message traffic. Look for missing messages, excessive error frames, or absent nodes.
- Check termination resistance across CANH/CANL (~60 Ω). If wrong, locate and repair missing or shorted termination resistors.
- Isolate the fault by disconnecting peripheral modules one at a time (if safe and vehicle-specific procedures permit) while monitoring the bus to find the failing node.
- Repair wiring, connectors, or replace failed termination. After repair, clear codes and verify normal communications and that C2100 does not return.
- If wiring and power/ground/termination check out and the module still fails to communicate, consider reprogramming or replacing the chassis control module per manufacturer procedure.
Likely causes
- Open/short on CAN high/low wiring or connector (most likely)
- Poor power or ground to the chassis control module
- Faulty or missing CAN termination resistor(s)
- Module internal failure or firmware mismatch
Fault status
Status
Chassis control module has detected an internal or network communication fault. Module is not communicating reliably on vehicle communication bus.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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