U0242 — Lost Communication With Headlamp Control Module B

Q: "Can I drive with this code?"

"It depends on the severity. If the vehicle runs normally, short trips are usually OK. If you notice performance issues, drivability problems, or warning lights beyond the check engine light, get it checked soon."

Q: "Will this code clear itself?"

"Some codes clear automatically after the underlying issue is fixed and several drive cycles pass. But the root cause must be addressed first."

Q: "How do I find the exact cause?"

"A code alone doesn't pinpoint the failed part. You need a diagnostic scan ($50-150 at most shops) that reads freeze frame data and live sensor readings to identify the specific component."

What Does U0242 Mean?

U0242 is a diagnostic trouble code indicating: Lost Communication With Headlamp Control Module B. This code relates to the network communication system. It has been reported in NHTSA complaints across 1 different vehicle models.

Symptoms of U0242

⚠️ Loss of engine power

Common Causes

🔍 Wiring or connector problem
🔍 Sensor or control module malfunction

Real Owner Reports

From NHTSA complaint database — actual owner descriptions.

"ALL IP WARNING LAMPS ILLUMINATED, LOSS OF POWER, STALLING, GAGE FLUCTUATION, INTERMITTENT DOOR LOCK OPERATION. VEHICLE WAS IN MOTION ON HIGHWAY WHEN THIS OCCURRED. ERROR CODES INCLUDE U0073, U0121M U0101, U0242 ( FROM DEALERSHIP ANALYSIS). CAUSE UNKNOWN. VEHICLE HAS BEEN IN DEALERSHIP MORE THAN 7 WE"
— Chevrolet Tahoe owner, 01/18/2018

Source: NHTSA Complaints Database

Most Reported Vehicles for U0242

Based on NHTSA owner complaint data.

#	Vehicle	Reports
1	CHEVROLET TAHOE

Frequently Asked Questions

Can I drive with this code?

It depends on the severity. If the vehicle runs normally, short trips are usually OK. If you notice performance issues, drivability problems, or warning lights beyond the check engine light, get it checked soon.

Will this code clear itself?

Some codes clear automatically after the underlying issue is fixed and several drive cycles pass. But the root cause must be addressed first.

How do I find the exact cause?

A code alone doesn't pinpoint the failed part. You need a diagnostic scan ($50-150 at most shops) that reads freeze frame data and live sensor readings to identify the specific component.

What To Do Next

Possible Fixes

🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
🔧 Test the relevant sensor(s) with a multimeter before replacing
🔧 Inspect wiring harness and connectors for damage, corrosion, or loose connections
🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

U0242: Lost Communication With Headlamp Control Module B