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U05A4 Particulate Matter Sensor Received Invalid Data From ECM/PCM

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

A diesel particulate matter sensor has its own control unit, which needs engine controller data to run its measuring and burn-off cycles. U05A4 is reported when that unit cannot accept what the engine controller sends. FCA lists it in bulletins 18-008-23 (2019 Jeep Compass with 1.6 or 2.0 L diesel) and 18-010-23 (2020 Compass 1.6): with the MIL on, U05A4 may appear among many PM sensor P-codes and U02A3, and the cure is new PCM software; only P2002 calls for a new filter and sensor. CARB 1968.2 requires PM sensor faults to be caught before the sensor stops being usable for filter monitoring. U04A4 is the reverse direction, U02A3 total silence. Expect a MIL and an incomplete filter test, with normal driving.

Likely causes

Engine controller software issue (FCA PCM update)
Damaged CAN or supply wiring to the PM sensor unit
PM sensor control unit faulty or wrong variant

Symptoms

  • Check engine light on
  • Several particulate matter sensor codes stored at once
  • Particulate filter monitor not completing

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–700
Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

pm sensorecm

Related codes

U04A4U02A3U04B2P24AF

References: static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.