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Home / DTC / C1026 — Chassis Control Module Internal Fault

C1026 — Chassis Control Module Internal Fault

Detailed page for trouble code C1026.

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C1026

Generic C — Chassis

Chassis Control Module Internal Fault

Brand: Generic
Type: C — Chassis
Views: UK: 2 EN: 1 RU: 0
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Page language: EN

Causes

  • Internal hardware or component failure inside the chassis control module (CCM)
  • Corrupted or failed module firmware/flash memory
  • Intermittent or low module supply voltage (battery, fuses, ignition feed)
  • Poor ground or high ground resistance at module
  • CAN/LIN bus communication errors (shorts, opens, high bus load)
  • Connector corrosion, bent pins, water intrusion, or mechanical damage

Symptoms

  • Chassis-related warning lamps illuminated (ABS, ESC, traction control, chassis fault)
  • Loss or intermittent operation of ABS/ESC/traction control functions
  • Module not responding or not present on network when scanned
  • Intermittent or persistent DTCs related to chassis or communications
  • Unexpected vehicle behavior under braking or stability control events
  • Vehicle may enter reduced-function mode or disable certain features

What to check

  • Read all stored DTCs and freeze-frame data; note present and historic codes
  • Check for related communication U-codes (U0100, U0121, U0140) that indicate bus issues
  • Verify battery voltage with ignition ON (acceptable 11.5–14.5 V) and check fuses/relays feeding the CCM
  • Inspect CCM connector for corrosion, bent pins, moisture, or damage; ensure secure mating
  • Measure module supply and ground at the connector; check ground resistance to chassis
  • Scan CAN/LIN bus activity: verify CAN_H/CAN_L differential and bus termination/resistance (~60Ω total)

Signal parameters

  • Module supply voltage (key ON): ~12 V (acceptable ~11.5–14.5 V)
  • Ground resistance to chassis: low (typically
  • CAN bus idle differential voltage: approx. 2.5 V (CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V with ~1 V swing on activity)
  • CAN bus termination resistance: ~60 Ω across CAN_H and CAN_L (two 120 Ω terminators)
  • Module wake/response on the bus: module should appear in network scan and respond to diagnostic requests
  • Abs/ESC sensor inputs: wheel speed sensor voltages/pulses should be within expected ranges when rotating

Diagnostic algorithm

  1. Connect a professional scan tool; read and record C1026 plus any related codes and freeze-frame data.
  2. Clear codes and perform a key cycle; re-scan to see if C1026 returns and note conditions when it sets.
  3. Check battery voltage, fuses, and relay circuits feeding the CCM. Repair any power-feed faults.
  4. Visually inspect the CCM connector and harness for corrosion, water, chafing, or damaged pins; repair as needed.
  5. Measure supply and ground at the CCM connector; confirm proper voltages and low ground resistance.
  6. Diagnose CAN/LIN network: verify bus voltages, termination resistance, and module presence on the bus; repair wiring faults.
  7. Review freeze-frame and related codes (U-codes, wheel sensors etc.) to determine if another component causes the fault.
  8. If wiring and power/ground are good and communication is intermittent or module fails self-tests, check for available software updates or reflash/reprogram the CCM per OEM procedure.
  9. If reflash does not clear the fault and internal diagnostics still indicate failure, replace the CCM with a correctly programmed unit and verify functionality.
  10. After any repair or replacement, clear codes and road-test to confirm system operation; monitor for reoccurrence.

Likely causes

  • Loss of proper supply voltage or poor ground at the CCM
  • CAN bus communication fault between CCM and other modules
  • Firmware corruption or failed module internal memory
  • Damaged or corroded connector/pins at the CCM
  • Internal electronics failure within the CCM

Fault status

⚠️ Status
Chassis Control Module internal fault — module self-test failed or internal error detected. Module may be unresponsive or communicating incorrectly; further electric/communication diagnosis required.
🔴 Repair difficulty: Hard
⏱️ Diagnostic time: 1-3 hours

Similar codes

C1020 C1025 C1030 U0100 U0121 U0140
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