U069ALost Communication With Exhaust Gas Temperature Sensor Bank 1 Sensor 3
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- The third exhaust temperature sensor on bank 1 usually sits in the aftertreatment, ahead of the filter or SCR stage. GM covers U069A in both 2025 diesel tables, 25OBDG04A and 25OBDG04B: a SENT sensor whose output was switched off by an internal fault, or that sends faulty or outdated messages, fails the check once 19 readings out of 25, taken every 100 ms, are bad. The test waits for the sensor start-up delay and skips cranking; Type A, so the lamp lights in the first faulty trip. GM's regeneration control reads EGT 3 as the temperature ahead of the particulate filter, and the circuit-low test P242C treats a digital reading under -72.8 °C as faulty. Ford's 2023 diesels have sensor 3 as an analog probe (P242C/P242D, below 0.10 V or above 2.66 V). Sensor 4 is U069B.
- What you may notice
- Check engine light, on GM diesels in the first trip
- Particulate filter regeneration blocked or postponed
- Further code for the controller input
- Likely causes
- LikelySensor harness along the aftertreatment burnt or chafed
- PossibleElectronics module of the thermocouple sensor failed
- PossibleConnector corroded
- RareController input fault
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.