P2078
Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit High (Bank 1)
IMT position sensor at bank 1 reads above upper plausibility — open signal or short to B+. The intake manifold runner control (IMRC) flaps tune intake geometry for filling efficiency across the rpm range; stuck flaps cost part-load torque and can set lean codes.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open signal lineCommon
- Connector pins corroded - high contact resistanceLess likely
- Supply wire pinched against B+ sourceLess likely
Parts involved
- Imt Position Sensor
P2078 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.