P2078
Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit High Bank 1
Fuel & air metering
Generic OBD-II
Medium
What it means
P2078 means the intake manifold tuning valve position sensor on bank 1 is reporting a voltage that is too high, usually from a short-to-power or open. This sensor tells the PCM where the tuning valve is set. A bad reading can slightly affect intake tuning and power in part of the rev range, but it does not cause a no-start. The engine runs and starts normally.
Medium
Can I keep driving? Drivable, though power may feel down in part of the rev range; not urgent, but worth fixing to restore full response.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or hesitation in part of the rev range
- Slightly rough idle
- Minor drop in fuel economy
Common causes
Most likely first
- IMT valve position sensor circuit shorted to power or openLikely
- Faulty intake manifold tuning valve position sensor/switchCommon
- Damaged wiring or corroded connector at the valveCommon
- Faulty or stuck intake manifold tuning valve reporting an out-of-range positionLess often
- Faulty PCM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the valve wiring and connector for shorts or corrosion.
- Check the position sensor's signal voltage against the valve's actual position with a scan tool.
- Repair any short-to-power or open in the circuit.
- Replace the IMT valve or its position sensor/switch if the signal stays high.
- Clear the code and re-test; consider the PCM only after wiring checks out.
FAQ
Quick answers
Is it safe to drive with P2078?+
Yes — it's a position-sensor circuit fault that mainly affects intake tuning, so it won't strand you, but fix it to restore full performance.
Can I just clear P2078?+
It returns until the high-reading sensor or wiring is repaired; clearing only helps confirm the fix.
Related codes
Often seen with P2078
Read & clear P2078 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX