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U0696 Lost Communication With Particulate Filter Pressure Sensor C

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

In GM's 2025 diesel tables 25OBDG04A and 25OBDG04B, sensor C is the downstream relative pressure sensor, which reads the gauge pressure behind the particulate filter and carries its own temperature element (lost communication there is U06B6). U0696 is set when the sensor reports message faults above a fixed count or when its newest message is too old, judged as 158 failures in 200 samples at 12.5 ms intervals. Being Type A, it turns on the lamp in the first trip. GM keeps offset errors at standstill (P2CE5) and a frozen signal (P2CE6) apart. Ford's 2024 gasoline summary lists U0696 with P2CE5 for SENT filter pressure sensors, checked continuously with 5 s to register. Without this value, back pressure and filter load are estimated. Sensor D is U0697.

Likely causes

Wiring to the downstream pressure sensor damaged by heat or chafing

Internal sensor fault that switches off the SENT output

Connector corroded by road splash

Symptoms

Check engine light, on GM diesels in the first trip
Particulate filter regeneration based on estimates or delayed

Repair estimate

DifficultyMediumDIY possible

Parts and labour€60–400

Time0.3–1.5 h

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

Parts involved

dpf pressure sensor cvehicle bus wiring

References: gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com.