P3492 records a high condition on the control circuit of the cylinder 12 deactivation or intake valve actuator, generally a short to a supply voltage seen while the output is commanded on. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. The Variable displacement overview notes that a V12 can stop up to six cylinders, and the production engines doing so (Mercedes M137, Lamborghini Aventador, Bentley W12) differ widely in method, from a hydraulic solenoid pack (M137) to bank shut-off with the valves left running (Bentley). Only a design with valve actuators has a cylinder 12 actuator to short. Expect deactivation to be inhibited and the engine to run on all twelve. P3489 and P3491 are the electrical siblings, P3496 the exhaust high code.
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
- Engine runs permanently on twelve cylinders
Most likely causes
- Cylinder 12 control wire shorted to supply voltage
- Shorted turns in the cylinder 12 actuator
- Engine control module output damaged
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 P3492 means
- P: Powertrain: engine and transmission
- 3: Generic or manufacturer code, depending on the range
- 4: Emissions
- 92: Specific fault in that system
Frequently asked questions
Can I keep driving with code P3492?
Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
What causes code P3492?
The most common causes are: cylinder 12 control wire shorted to supply voltage; shorted turns in the cylinder 12 actuator; engine control module output damaged.
Related codes
- P3489Cylinder 12 Deactivation/Intake Valve Control Circuit/Open
- P3490Cylinder 12 Deactivation/Intake Valve Control Performance
- P3491Cylinder 12 Deactivation/Intake Valve Control Circuit Low
- P3496Cylinder 12 Exhaust Valve Control Circuit High
- P3497Cylinder Deactivation System Bank 2
Sources
- law.cornell.edu: 13 CCR 1968.2
- en.wikipedia.org: Variable displacement
- en.wikipedia.org: Mercedes Benz M137 engine
- newatlas.com: 24363
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.