P3470 covers a cylinder 9 exhaust valve that does not follow its deactivation command although the control circuit shows no electrical fault. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. The risk behind it is described in a Ford patent: an exhaust valve that keeps opening after shut-off spoils the gas cushion in the cylinder and can be detected from changes in exhaust pressure. The opposite case, a valve that stays shut on reactivation, traps hot gas under pressure. Neither the Lamborghini Aventador V12 nor the Huracán V10 publishes how their bank shut-off works, and Audi's V10 simply cuts injection and ignition, so this check has no known user. Electrical faults of the same actuator: P3469, P3471, P3472.
Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
Cylinder 9 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Check engine lamp on
- Knock or jolt when cylinder 9 comes back in
- Misfire on cylinder 9 (P0309)
Most likely causes
- Exhaust switching element of cylinder 9 stuck
- Insufficient oil pressure for the exhaust switch
- Exhaust actuator sluggish
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It affects emissions.
What each character of P3470 means
- P: Powertrain: engine and transmission
- 3: Generic or manufacturer code, depending on the range
- 4: Emissions
- 70: Specific fault in that system
Frequently asked questions
Can I keep driving with code P3470?
Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
What causes code P3470?
The most common causes are: exhaust switching element of cylinder 9 stuck; insufficient oil pressure for the exhaust switch; exhaust actuator sluggish.
Related codes
- P3469Cylinder 9 Exhaust Valve Control Circuit/Open
- P3471Cylinder 9 Exhaust Valve Control Circuit Low
- P3472Cylinder 9 Exhaust Valve Control Circuit High
- P3466Cylinder 9 Deactivation/Intake Valve Control Performance
- P0309Cylinder 9 Misfire Detected
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.