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U064F Lost Communication With Intake Manifold Runner Position Sensor Bank 1

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

Diesel swirl flaps partly close one intake port per cylinder at low load so the charge spins and mixes better; a motor moves them and a sensor reports the angle. In GM's 2025 diesel table 25OBDG04B that sensor transmits by SENT, and U064F covers a missing or corrupt stream: an internal fault flag or message error, or position data not refreshed for over 6.25 ms with the line held steadily high or low. It must show in 480 of 600 checks taken every 6.25 ms, after cranking and with more than 11 V at the relay. As Type B it turns on the MIL only after a second failed trip. While U064F is active, GM does not judge the raw value (P2016 below 1 %, P2017 above 99 %); motor circuit faults are P2008 to P2010, failed end-stop learning P200A.

Likely causes

Oil or soot in the actuator connector, corroded pins

Position sensor in the swirl flap actuator failed

SENT signal wire chafed, open or shorted on the engine

Engine controller SENT input faulty

Symptoms

MIL after two trips with the fault
Swirl flaps left in default position, slightly rougher or smokier low-load running
Often no noticeable change in driving

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€60–900

Time0.5–3 h

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

Parts involved

intake runner position sensor bank 1vehicle bus wiring

References: gsi.ext.gm.com, en.wikipedia.org, law.cornell.edu.