U0602: Lost Communication With Particulate Filter Pressure Sensor B

What it means

The vehicle bus reports loss of communication with smart particulate filter (DPF) differential pressure sensor B. The ECM cannot read soot loading via this channel and may switch to a model-based estimate.

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

Particulate filter pressure sensor B sends pressure information over the vehicle network so the engine controller can assess filter loading. U0602 sets when the controller or another module loses communication with sensor B and cannot receive that channel’s data.

Common causes

Most likely first.

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

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Save freeze-frame data and scan all modules for other network faults and particulate-filter codes to see whether the loss is limited to sensor B.
2. Check the live data list for sensor B and compare it with sensor A or other available filter-pressure data; note missing or substituted readings.
3. Inspect sensor B’s connector and network harness for disconnection, corrosion, chafing, heat damage, or water intrusion.
4. Check the sensor’s specified power, ground, and network signals against the manufacturer’s service information, especially if other devices on the same bus are also offline.
5. If wiring and power are sound, test sensor B communication and verify module configuration before replacing the sensor or investigating a controller.

Common fixes

• Reconnect or repair a loose, corroded, or damaged sensor B connector or network wire.
• Restore the sensor’s specified power or ground.
• Repair a shared network fault if other modules also lose communication.
• Replace particulate filter pressure sensor B if testing confirms it has failed.
• Correct a configuration or controller fault if vehicle-specific diagnosis identifies one.

Can I keep driving?

You may be able to drive briefly if the vehicle has normal power and no severe warning, but arrange diagnosis soon and avoid heavy-load or long trips. Missing sensor B data can disrupt filter monitoring or regeneration and may lead to emissions faults or reduced power.