P2078Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit High (Bank 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- Check engine light (GM Type B; Ford without MIL)
- Valve monitoring suspended
- Possibly less power in one rpm band
- Likely causes
- LikelySensor ground open, e.g. pushed-back pin in the connector
- PossibleSignal wire shorted to 5 V reference or battery voltage
- PossibleElectronics of the actuator unit defective
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.