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Module communication

U0442 Invalid data from the engine control module (ECM) B

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U0442 means: Invalid data from the engine control module (ECM) B. The car's control modules talk to each other over the CAN bus. Drive gently and have the car checked soon. The repair usually costs about €60–800 in Estonia. The most common cause: low or unstable battery voltage.

Is it safe to drive?Get it checked soonDrive gently and have the car checked soon.
Typical repair cost€60–800parts and labour in Estonia

What it means

The car's control modules talk to each other over the CAN bus. One module isn't getting messages from another, or the data it gets is faulty.

What you may notice

  • Several warning lights at once
  • Some function doesn't work
  • The car may not start or may go into limp mode

What could be wrong

  1. 1Low or unstable battery voltage
  2. 2Module supply, fuse or ground
  3. 3Broken or corroded CAN wire or connector
  4. 4Faulty module or wrong software

Repair difficulty: Moderate

What you can check yourself

Check the battery and terminals first. A great many communication codes appear after a weak battery or a jump start. Best left to a workshop. It needs a diagnostic tool and experience.

How we fix it

  1. We read codes from all modules and see which one isn't answering
  2. We measure the module supply and the CAN bus
  3. We repair the wire or connector
  4. We update the software or replace the module

Standard SAE description: Invalid Data Received From ECM/PCM "B"

Related symptoms: Loss of power or limp mode

Check the fuse · If a light, the horn, wipers, a socket or the fuel pump is dead, a blown fuse may be the cause.Fuse boxes by car →

Want a definite answer?

Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.

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Questions

What does fault code U0442 mean?

Invalid data from the engine control module (ECM) B. The car's control modules talk to each other over the CAN bus. One module isn't getting messages from another, or the data it gets is faulty.

Can I drive with code U0442?

Drive gently and have the car checked soon.

How much does it cost to fix U0442?

Roughly €60–800 in Estonia. The price depends on exactly what has failed and on the car.

How is U0442 fixed?

We read codes from all modules and see which one isn't answering. We measure the module supply and the CAN bus. We repair the wire or connector. We update the software or replace the module.

Related codes

U0443Invalid data from the body control module (BCM) BU0444Invalid data from the body control module (BCM) CU0322Software mismatch with the body control module (BCM)U0323Software mismatch with the instrument clusterU0324Software mismatch with the climate control moduleB1318Battery voltage too low (body module)B1600PATS: key transponder signal not received

Based on AI combined with our hands-on workshop experience and knowledge. This information is general and prices are approximate (Estonian workshop rates). The same code can mean different things on different cars. Only an inspection of the car gives a definite answer.

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