Powertrain, generic (extended)

P2078 Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit High (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Opposite of P2077: the bank 1 valve feedback sits above its upper plausible limit. Typical triggers are a short to battery or 5 V on the signal line, or an open sensor ground. Because GM's percentage scale is reversed, its tables treat a position of 5 % or less as high (2007, 2015, 2018; the 2006 table names 0.05 %), with 320 failures in 400 samples and Type B. GM's newer 2023/2024 logic instead watches for a raw voltage above roughly 4.8 V. On FCA's 3.5L V6 (2007-2010) P2078 is the second manifold tuning valve code next to P2077, and the Chrysler tip warns against replacing the whole manifold before testing the actuator output. Ford lists the code without MIL. Note that GM blocks its stuck-valve checks while this code is active.

Likely causes

Sensor ground open, e.g. pushed-back pin in the connector
Signal wire shorted to 5 V reference or battery voltage
Electronics of the actuator unit defective

Symptoms

  • Check engine light (GM Type B; Ford without MIL)
  • Valve monitoring suspended
  • Possibly less power in one rpm band

Repair estimate

DifficultyEasyDIY possible
Parts and labour€20–350
Time0.3–2 h

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

Parts involved

imt position sensor

Related codes

P2077P2075P2076P207DP2070

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.