What does it mean?
P3419 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 3 Deactivation/Intake Valve Control Circuit Low . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- MIL (check engine lamp) on, often returning right after the code is cleared
- Cylinder deactivation disabled, so the engine runs on all cylinders and uses more fuel
- Rough idle and vibration, worse during mode transitions
- Ticking noise from the top of the engine
- Cylinder 3 misfire that can be felt at low rpm
- Reduced power on some vehicles as the module falls back to a protective strategy
Likely causes
- Control wire rubbed through and grounding against the cylinder head, a bracket or a loom clip
- Solenoid winding shorted internally to its own case
- Oil or coolant pooling in the connector and bridging the control pin to ground
- Harness pinched under a cover, manifold or engine mount after previous work
- Output driver in the PCM (powertrain control module) shorted on and holding the circuit low
- Poor previous repair, such as a taped splice that has grounded out
How to fix it
- Check for other low-circuit codes on the same bank, which would suggest a shared harness fault
- Unplug the cylinder 3 solenoid; if the code changes to an open circuit fault, the solenoid is the likely short
- With the solenoid and module both unplugged, measure resistance from the control wire to ground; a low value confirms a short to ground
- Follow the harness along the head and past every clip and bracket looking for chafe and crush damage
- Compare the solenoid winding resistance with a known-good solenoid on the same engine
- Repair or replace the damaged harness section, or fit a new solenoid if it tests shorted
- Clear the code, command the output on and off with the scan tool and road test to confirm the repair