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Home / DTC / C0801 — Chassis Control Module Communication Fault (C0801)

C0801 — Chassis Control Module Communication Fault (C0801)

Detailed page for trouble code C0801.

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C0801

Generic C — Chassis

Chassis Control Module Communication Fault (C0801)

Brand: Generic
Type: C — Chassis
Views: UK: 4 EN: 12 RU: 6
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Page language: EN

Causes

  • Open or shorted CAN/data bus wiring between CCM and other modules
  • Corroded, loose, or damaged connector at the CCM or other modules
  • Loss of module power or ground (blown fuse, poor ground)
  • Failed chassis control module (internal fault)
  • Bus termination resistor open or shorted
  • Another module dominating or flooding the bus (bus error state)

Symptoms

  • Chassis/traction/ABS warning lights illuminated
  • Loss or intermittent operation of stability control, traction control or related features
  • Some chassis-related functions not responding or operating incorrectly
  • Other modules report related communication or network errors
  • Inability for scan tool to communicate with CCM

What to check

  • Read stored, pending and freeze-frame data with a capable scan tool; note occurrence conditions
  • Attempt to communicate with CCM using OEM or capable scan tool
  • Verify battery voltage at rest and during cranking (12.4–12.9 V at rest typical)
  • Inspect CCM connector and harness for corrosion, bent pins, water intrusion, or physical damage
  • Check CCM power feed and ground circuits for proper voltage/continuity
  • Measure CAN bus idle voltages at CCM connector (CAN_H, CAN_L) and bus resistance

Signal parameters

  • CAN_H idle ≈ 2.5 V (typical), CAN_L idle ≈ 2.5 V (typical)
  • Dominant state: CAN_H ∼3.5 V, CAN_L ∼1.5 V (vehicle dependent)
  • Differential idle ≈ 0 V; dominant differential ≈ 2 V
  • Bus termination resistance ≈ 60 Ω total (two 120 Ω resistors in parallel typical)
  • Supply voltage to CCM: battery voltage present with ignition ON (vehicle-specific)
  • Nominal CAN data rate commonly 250–500 kbps (check vehicle spec)

Diagnostic algorithm

  1. Connect a scan tool and retrieve all network and chassis-related codes. Note freeze frame and how often C0801 is set (continuous vs intermittent).
  2. Attempt to communicate with the CCM using the scan tool. If the tool cannot communicate, confirm other modules on the same bus are reachable.
  3. Verify basic power: check relevant fuses, measure battery voltage at CCM power pins with ignition ON. Verify module ground(s) have low resistance to chassis.
  4. Visually inspect CCM connector and wiring: look for corrosion, bent pins, water entry, rodent damage, or stretched/abraded insulation.
  5. With ignition ON (engine off), measure CAN_H and CAN_L voltages at the CCM connector. Idle voltages should be near nominal (≈2.5 V).
  6. Measure termination resistance between CAN_H and CAN_L at two points; expect ~60 Ω. If open or significantly different, locate open/shorted termination resistors.
  7. Check for shorts to battery or ground on each CAN line (measure resistance to battery + and ground with battery disconnected where appropriate).
  8. If wiring and supply/ground are good, disconnect other modules on the same bus one at a time (or remove suspect modules) to determine if another device is faulting the bus.
  9. If the bus is healthy with other modules disconnected and CCM still does not communicate, consider reflash/update of CCM software per OEM procedure (if available) or module replacement after verifying no wiring faults.
  10. After repairs, clear codes, reconnect everything, confirm stable communication and perform a road test to verify the fault does not return.

Likely causes

  • Damaged harness or pin pushed out of connector at CCM
  • Corroded pins causing intermittent contact
  • Blown fuse or disconnected ground affecting CCM supply
  • Short to battery or ground on CAN_H or CAN_L
  • Failed CCM hardware or internal communication circuitry

Fault status

⚠️ Status
Chassis Control Module not communicating on the vehicle data bus. Communication timeouts or errors recorded; chassis-related systems may be degraded or unavailable.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

C0800 U0100 U0073 U0121 U0155
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