Invalid Data Received From Impact Classification System Module
The U0551 code means the vehicle's onboard diagnostic system has detected: Invalid Data Received From Impact Classification System Module. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $50 - $500 (usually the fault behind the bad data, not the network itself)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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What Are the Symptoms of U0551?
- Check Engine or related warning light on
- Functions relying on data from the Impact Classification System Module may act erratically
- Often intermittent
What Causes U0551? (Most Likely First)
- The Impact Classification System Module is transmitting, but its data is implausible - often a failing sensor feeding it High
- Intermittent wiring fault corrupting messages Moderate
- Software mismatch after service Moderate
- Failing Impact Classification System Module Low
Can I Still Drive with U0551?
Yes, but fix soon. U0551 is rated moderate severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring the light.
Frequently Asked Questions
What does U0551 mean?
U0551 means this module IS communicating with the Impact Classification System Module, but the data it sends fails plausibility checks. Diagnose the source module first.
Can I keep driving with U0551?
Usually yes for a short period. The affected function may be degraded, and intermittent wiring faults tend to worsen - diagnose soon.
Should I replace the module for U0551?
Not first. Most communication codes are power, ground, fuse, or wiring problems. Replace the module only after those test good - modules are expensive and often require programming.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose U0551?
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Scan the Impact Classification System Module itself - the invalid data usually traces to a fault code stored there.
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Fix any codes in the source module first; this code often clears with them.
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Check for recent programming or battery-disconnect events.
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If the source module is clean, monitor the specific data value flagged and follow the OEM pinpoint test.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Which Vehicles Commonly Get U0551?
- All OBD-II vehicles - network (U) codes are standardized across makes
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