P3495 points to a low signal, usually a short to ground, on the control line of the cylinder 12 exhaust valve actuator. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. The twelve-cylinder engines with deactivation (Bentley W12, Lamborghini Aventador V12, Mercedes M137) are not documented with a dedicated exhaust actuator per cylinder; the newer ones shut entire banks and keep the valves moving, as Bentley states for its W12. Where such an actuator does exist, the diagnosis follows the usual path: connector unplugged, resistance of the wire to ground, then the coil itself. P3493 is the open circuit, P3496 the short to voltage, and P3491 the low fault on the intake side of cylinder 12.
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 12 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Check engine lamp on
- Cylinder deactivation inactive
Most likely causes
- Exhaust actuator wire of cylinder 12 grounded
- Exhaust actuator with internal short
- Control module output faulty
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P3495 means
- P: Powertrain: engine and transmission
- 3: Generic or manufacturer code, depending on the range
- 4: Emissions
- 95: Specific fault in that system
Frequently asked questions
Can I keep driving with code P3495?
Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
What causes code P3495?
The most common causes are: exhaust actuator wire of cylinder 12 grounded; exhaust actuator with internal short; control module output faulty.
Related codes
- P3493Cylinder 12 Exhaust Valve Control Circuit/Open
- P3494Cylinder 12 Exhaust Valve Control Performance
- P3496Cylinder 12 Exhaust Valve Control Circuit High
- P3491Cylinder 12 Deactivation/Intake Valve Control Circuit Low
- P3497Cylinder Deactivation System Bank 2
Sources
- law.cornell.edu: 13 CCR 1968.2
- mobilityengineeringtech.com: 41966 sae ma 01159
- bentleymedia.com: 1611 end of an era as final bentley w12 engine han
- en.wikipedia.org: Mercedes Benz M137 engine
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.