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DTC codes / U06xx · Network communication / U068A

U068ALost Communication With Barometric Pressure Sensor C

U068A is a network communication fault indicating that a control module on the vehicle's data bus has lost contact with the barometric pressure sensor designated as Sensor C. The computer has detected that expected messages from this sensor are no longer arriving, which can affect fuel delivery, turbocharger control, and altitude compensation strategies.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaNetwork communication

Symptoms you may notice

  • Illumination of the malfunction indicator lamp (MIL) on the dashboard
  • Often no symptoms besides the warning light, especially if the sensor is only used for trim correction
  • Rough running or poor fuel economy if the engine control module (ECM) substitutes a default barometric value
  • Reduced turbocharger performance or boost control issues on forced-induction engines
  • Intermittent stalling or hesitation during altitude changes or heavy load
  • Other communication-related warning lights if the fault lies on a shared bus segment

Common causes, most likely first

  1. Damaged or corroded wiring harness between the barometric pressure sensor C and its control module
  2. Faulty barometric pressure sensor C itself, internally shorted or open
  3. Loose or contaminated electrical connector at the sensor or at the module
  4. Water intrusion or rodent damage in the harness routing
  5. Failed control module that cannot communicate on the bus, though this is less common
  6. Network bus fault such as a shorted CAN (Controller Area Network) line or failed terminating resistor affecting multiple modules

How to diagnose and fix it

  1. Connect a scan tool and verify the exact code along with any related communication codes in all modules
  2. Inspect the barometric pressure sensor C connector and harness for corrosion, looseness, or physical damage
  3. Check the sensor reference voltage and ground at the connector with a digital multimeter
  4. Perform a wiggle test on the harness while watching live sensor data to reveal intermittent faults
  5. Measure resistance and continuity on the communication lines between the sensor and the control module
  6. If wiring and connectors are good, substitute a known-good sensor and clear the code to see if it returns
  7. If the fault persists after sensor replacement, diagnose the control module and network bus integrity with an oscilloscope

What most technicians overlook on U068A

  • A barometric pressure sensor C fault often sets because of a poor ground shared with other sensors, not because the sensor itself has failed.
  • On some vehicles the barometric pressure sensor is integrated into the mass airflow sensor or the engine control module, so replacing the standalone sensor may not be possible.
  • U068A can be a stored history code from a low-battery event or jump-start, so always clear it and verify it returns before condemning parts.
  • A shorted CAN bus line elsewhere on the network can prevent the barometric sensor message from reaching the module, mimicking a sensor failure.
  • Altitude changes during driving can trigger the code intermittently if the sensor signal is marginal, so test under varying engine load and elevation if possible.

Can I keep driving with U068A?

The vehicle is generally safe to drive with U068A because the engine control module substitutes a default barometric value, but you may notice reduced performance or fuel economy. Avoid heavy towing or sustained high-altitude driving until the fault is repaired, and address the code promptly to prevent secondary drivability issues.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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