P3459Cylinder 8 Deactivation/Intake Valve Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- When the ground-side control line of the cylinder 8 deactivation solenoid touches ground, the ECM stores P3459. GM publishes this test for the 2019 L84 V8 with Dynamic Fuel Management: driver off, impedance below 0.5 ohm to ground, a minimum of 11 V on the relay feed and 425 rpm, 20 errors in 25 samples, Type B. Some GM controllers log P3457 at the same time. Because a DFM engine may skip any cylinder, a fault on cylinder 8 shuts down a system that otherwise uses this cylinder routinely; GM's LTA and LT2 also include cylinder 8 in their fixed deactivation set. A ground short on the solenoid's high-side feed has its own GM code, P311A. P3460 is the short to power.
- What you may notice
- Check engine lamp on after the second trip
- Engine runs on all eight cylinders at all times
- Higher fuel consumption
- Likely causes
- LikelyCylinder 8 control wire grounded through damaged insulation
- PossibleInternal short in the cylinder 8 solenoid
- RareContamination in the solenoid connector
- RareOutput driver in the engine control module damaged
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.