Lost Communication With Exhaust Aftertreatment Module
The U0264 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Exhaust Aftertreatment Module. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $400 - $2,500 (parts and labor)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- DEF system warning light on
- Reduced engine power warning
- Speed limited to 55 mph or less
- Diesel exhaust fluid quality poor message
- SCR catalyst efficiency warning
Probable Causes (Ranked by Likelihood)
- Failed aftertreatment control module Very High
- DEF injector failure High
- CAN bus wiring fault to aftertreatment Moderate
- Contaminated DEF fluid Low
Step-by-Step Diagnostic Procedure
-
Check DEF fluid level and quality
-
Scan aftertreatment module for codes
-
Test DEF injector operation
-
Inspect CAN bus wiring to module
Frequently Asked Questions
Can I drive with U0264?
Only short distances. The vehicle may enter speed-limited mode after a period of time.
What causes U0264?
Usually a failed aftertreatment module or DEF injector. Contaminated DEF is also a common cause.
How much does U0264 cost to fix?
Between $400 and $2,500 depending on the component.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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