P3463: Cylinder 8 Exhaust Valve Control Circuit Low

P3463 would mean that the control line of a dedicated cylinder 8 exhaust actuator is shorted to ground. No manufacturer documents this code publicly. On the only engines with documented cylinder 8 deactivation, GM's L84 and its relatives, one solenoid handles both valves, and GM reports a ground short on it as P3459, testing for less than 0.5 ohm to ground with the driver off. NHTSA's summary of the system lists solenoid driver circuit faults among the reasons the ECM inhibits deactivation, which is also what a driver would notice here: the engine keeps all eight cylinders running and uses a little more fuel. P3461 covers an open, P3462 the function and P3464 a short to power in this exhaust group.

Cylinder 8 is numbered according to the manufacturer: check your engine's manual before working on it.

Symptoms

• Check engine lamp on
• Engine stays on all eight cylinders

Most likely causes

• Cylinder 8 exhaust actuator wire shorted to the engine block
• Exhaust actuator shorted to ground internally
• Driver stage in the engine control module faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the oil level and condition before anything else
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Check the solenoid valve's connector
4. Compare commanded and actual angles in live data
5. Test the solenoid valve and its filter, if it has one
6. Check the engine timing if there is chain noise

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P3463 means

• P: Powertrain: engine and transmission
• 3: Generic or manufacturer code, depending on the range
• 4: Emissions
• 63: Specific fault in that system

Frequently asked questions

Can I keep driving with code P3463?

Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

What causes code P3463?

The most common causes are: cylinder 8 exhaust actuator wire shorted to the engine block; exhaust actuator shorted to ground internally; driver stage in the engine control module faulty.

Related codes

• P3461Cylinder 8 Exhaust Valve Control Circuit/Open
• P3462Cylinder 8 Exhaust Valve Control Performance
• P3464Cylinder 8 Exhaust Valve Control Circuit High
• P3459Cylinder 8 Deactivation/Intake Valve Control Circuit Low
• P3497Cylinder Deactivation System Bank 2

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 19OBDG03B Diagnostics
• static.nhtsa.gov: INRD PE25001 11969

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.