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U069B Lost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 4

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

Sensor 4 is the fourth temperature point along the bank 1 exhaust. Of GM's 2025 diesel tables only 25OBDG04A contains U069A's partner U069B; 25OBDG04B ends at sensor 3. The logic is the same SENT check as for sensor 3, 19 bad samples of 25 at 100 ms after the sensor's start-up delay, Type A. What differs is the role: in the second stage of GM's hydrocarbon dosing control (P144E) EGT 4 supplies the temperature ahead of the filter, so losing it disturbs regeneration. GM rates an open or high circuit on this probe (P2471) as Type A. Ford's 2023 diesels read sensor 4 as an analog probe (P2470/P2471) and check it against the other sensors after a cold start (P246F). Sensience offers such probes with SENT or CAN output.

Likely causes

Harness to sensor 4 damaged by heat during regeneration

Sensor electronics failed

Connector corroded

Symptoms

Check engine light
Regeneration interrupted or not started

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 1 sensor 4vehicle bus wiring

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