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DTC codes / U35xx · Network communication / U355E

U355EExpander Inlet Pressure Sensor 2 Circuit

U355E indicates that the powertrain control module has detected an electrical fault in the circuit for the Expander Inlet Pressure Sensor 2, which is a pressure sensor used in the vehicle's air suspension or central tire inflation system to monitor inlet pressure. The computer compares the sensor's signal voltage to expected values and sets this code when the signal is out of range, intermittent, or missing entirely.

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 system defaults to a safe pressure.
  • Inability to adjust suspension height or tire pressure, depending on the system.
  • A message on the driver information center indicating a suspension or tire pressure fault.
  • Rough ride quality or uneven vehicle stance if the expander system is part of the air suspension.
  • The compressor may run excessively or not at all, depending on the fault mode.

Common causes, most likely first

  1. Damaged or disconnected wiring harness at the sensor connector.
  2. Corroded or loose electrical terminals at the sensor or control module.
  3. Failed Expander Inlet Pressure Sensor 2.
  4. Open or short circuit in the signal or reference voltage wire.
  5. Water intrusion into the sensor or connector causing signal corruption.
  6. Faulty power or ground supply to the sensor.
  7. Rarely, a software issue or internal fault in the control module.

How to diagnose and fix it

  1. Perform a visual inspection of the sensor and its wiring for obvious damage, corrosion, or loose connections.
  2. Use a scan tool to check for other codes and view live data for the Expander Inlet Pressure Sensor 2 to see if the signal is stuck or erratic.
  3. Disconnect the sensor and check for the correct reference voltage (usually 5V) and good ground at the connector with a multimeter.
  4. Check the resistance of the sensor itself if specifications are available, and compare to expected values.
  5. Inspect the wiring harness between the sensor and the control module for continuity and shorts to ground or power.
  6. If wiring and sensor test good, suspect the control module and perform further diagnostics before replacement.
  7. Clear the code and test-drive the vehicle to verify the repair and ensure the code does not return.

Expander sensor faults often misdiagnosed

  • A common mistake is replacing the Expander Inlet Pressure Sensor 2 without checking the reference voltage; a missing 5V supply will set the same code and mimic a failed sensor.
  • Water intrusion into the sensor connector is a frequent cause on vehicles that operate in wet or muddy conditions, and the corrosion may not be visible until the connector is opened.
  • The code can be set by a momentary glitch, so always check for stored history codes and review freeze-frame data before condemning parts.
  • On some vehicles, the expander system shares power or ground with other sensors, so a fault in a related circuit can trigger U355E along with other codes.
  • A weak battery or charging system issue can cause intermittent sensor codes; always verify battery voltage and connections before deep diagnostics.

Can I keep driving with U355E?

You can usually drive the vehicle with this code, but the affected system (air suspension or tire inflation) may not function correctly, potentially affecting ride height or tire pressure. Avoid loading the vehicle heavily or driving at high speeds until the fault is repaired, and address the issue promptly to prevent secondary damage.

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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