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U069D Lost Communication With Exhaust Gas Temperature Sensor Bank 2 Sensor 4

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

Sensor 4 is normally the final measuring position in the bank 2 exhaust, often placed further down the aftertreatment where the controller judges how hot the gas leaves the filter or catalyst stages. U069D reports that this digital probe has gone silent on its data link. Code-level documentation from a maker is not public; CARB only demands that a coded digital input which stops talking gets a code of its own. Sensience builds such probes from a type N thermocouple and a control module that handles up to four probes on J1939 CAN or one or two on SENT, so one failed module can silence several positions at once. On bank 1 only GM's 25OBDG04A contains the matching code U069B, rated Type A. Wiring faults of an analog probe at this point use P2473 to P2477, while U069C is the third probe. Expect a lit MIL and regeneration being delayed.

Likely causes

Probe lead melted or torn near the rear aftertreatment

Electronics unit of the probe dead

Supply fuse or feed wire of the probe faulty

Symptoms

Check engine light
Regeneration delayed or cancelled

Repair estimate

DifficultyMediumDIY possible

Parts and labour€60–450

Time0.5–2 h

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

Parts involved

egt sensor bank 2 sensor 4vehicle bus wiring

References: law.cornell.edu, gsi.ext.gm.com, sensience.com.