Lost Communication with Impact Classification Module
The U0250 code indicates that the engine control module (ECM/PCM) has lost communication with the Impact Classification System Module. This module evaluates collision severity and controls deployment of passive safety systems such as airbags and seatbelt pretensioners. Loss of communication can prevent these critical systems from deploying correctly during a crash. Communication between modules typically occurs over the CAN bus network; when the impact classification module fails to respond within the expected time, this diagnostic trouble code is set. The module may be integrated into the airbag control unit (SDM) or be a separate unit, depending on vehicle architecture.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty impact classification module (internal damage or hardware failure)
- Open, shorted, or incorrect resistance in the CAN bus wiring
- Corroded, bent, or loose connector pins at the impact classification module
- Blown fuse, poor ground, or voltage drop affecting module power supply
- Faulty master control module (ECM/PCM) that manages bus communication
- Electromagnetic interference disrupting data signal integrity
- Corrupted or outdated module software requiring reprogramming
3. Symptoms You Will Notice
- Airbag warning light illuminated
- Possible failure of airbags or seatbelt pretensioners to deploy in a collision
4. Step-by-Step Diagnosis
Scan for all stored codes and note any related U-codes or B-codes
Check for technical service bulletins (TSBs) related to U0250 for the specific vehicle
Inspect the impact classification module connector for corrosion, bent pins, or looseness
Test CAN bus wiring for continuity, shorts, and proper termination resistance (typically 60 ohms)
Verify power and ground at the impact classification module (check fuses, relays, and voltage)
If all wiring and power are OK, suspect a faulty module or ECM/PCM; attempt reprogramming or replacement
5. Frequently Asked Questions
Is it safe to drive?▼
No, it is not safe to drive. The U0250 code indicates a loss of communication with the impact classification module, which could prevent airbags and seatbelt pretensioners from deploying in a crash. Have the vehicle diagnosed and repaired immediately.
How much does it cost to fix?▼
The cost varies widely depending on the root cause. A simple wiring repair or fuse replacement may cost $100–$200, while replacing the impact classification module can range from $400 to $1,200 including labor and programming. Diagnostic fees are typically $100–$150.