C0257 moderate

Active Suspension Control Module Communication Error

The C0257 code means the vehicle's onboard diagnostic system has detected: Active Suspension Control Module Communication Error. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
hard
Estimated cost
$100 - $1500 (parts and labor)
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Common Symptoms

  • Service ride control message
  • All four corners revert to default damping
  • Suspension warning light on
  • Ride quality noticeably different
  • Other modules may show communication DTCs

Probable Causes (Ranked by Likelihood)

  • CAN bus wiring fault to suspension module Very High
  • Suspension control module power supply issue High
  • Corroded module connector Moderate
  • Suspension control module internal failure Moderate
  • CAN bus termination resistor failure Low

Step-by-Step Diagnostic Procedure

  1. Scan all modules for communication-related DTCs

  2. Check CAN bus wiring at the suspension control module connector

  3. Verify power and ground at the suspension module

  4. Inspect the module connector for corrosion, bent pins, or water intrusion

  5. Check for CAN bus resistance -- should measure approximately 60 ohms between CAN high and low

Frequently Asked Questions

What happens when the suspension module loses communication?

The active shocks revert to a default damping rate -- usually a medium setting. You lose the adaptive ride quality but the vehicle is still safe to drive. The ride may feel stiffer or softer than normal.

Can a CAN bus problem affect other systems?

Yes. The CAN bus is a shared communication network. A fault in one area can affect multiple modules. Look for communication codes in other modules like ABS, engine, and transmission.

How do I test the CAN bus?

Using a multimeter, measure resistance between CAN high and CAN low at the OBD-II port. Normal reading is approximately 60 ohms. You can also use an oscilloscope to check for clean CAN bus waveforms.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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