OBD-II fault code

U0654: Lost Communication With Diesel Intake Air Flow A Position Sensor

What it means

A control module has stopped receiving expected network messages from the diesel intake air flow A position sensor. The effect on intake air control depends on the vehicle's system design.

At a glance

  • Usually lights the warning light of the system that lost communication
  • Affects emissions; the car can fail an emissions test

How it works

The diesel intake air flow A position sensor reports the position of an intake-air control component. This code sets when a module stops receiving the expected network messages from sensor A, leaving the control system without that position feedback.

Common causes

Most likely first.

  1. Bus wiring open or shorted
  2. Module without power or ground
  3. Module failed

Symptoms

  • Warning light or message related to the affected system
  • Engine performance may be affected

How to diagnose it

  1. Record freeze-frame data and scan all modules for intake-air and communication codes to identify when sensor A messages stopped.
  2. Check live data specifically for the diesel intake air flow A position reading and whether it changes with an intake-control command.
  3. Inspect sensor A's connector and network wiring for corrosion, loose pins, chafing, or damage from heat and vibration.
  4. Check power and ground at sensor A or its associated module using the manufacturer's wiring information.
  5. Test the network circuit to sensor A for opens or shorts, then assess the sensor or module if wiring and electrical feeds pass.

Common fixes

  • Reconnect or clean the intake air flow A position sensor connector.
  • Repair damaged network wiring or connector terminals serving sensor A.
  • Restore the sensor module's power or ground.
  • Replace sensor A or its associated module if the circuit checks pass but communication remains lost.

Can I keep driving?

A short, gentle drive may be possible if the engine runs normally, but avoid towing or hard acceleration if power is reduced. Missing intake-position feedback can worsen drivability and emissions.

A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together

This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.

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