What does it mean?
P3429 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 4 Exhaust Valve Control Circuit/Open . 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 with the variable exhaust valve function disabled
- The engine feels dull and lacks the usual pull at higher rpm
- Uneven idle and an irregular exhaust beat
- Ticking from the valve train close to cylinder 4
- Fuel consumption above normal and a possible cylinder 4 misfire
- Hesitation when accelerating in the mid range
Likely causes
- Connector at the cylinder 4 exhaust solenoid loose, unlatched or with a displaced terminal
- Control wire broken or cut through by chafing against the head or a bracket
- Oil migration through the harness insulating the terminal contact faces
- Open winding inside the exhaust valve control solenoid
- Loss of supply voltage to the solenoid group through a blown fuse or open feed
- Heat-damaged connector on the exhaust side of the cylinder head
How to fix it
- Read freeze frame and check whether the code is currently active or intermittent
- Unplug the solenoid and inspect the terminals for oil, corrosion and push-back
- Measure coil resistance at the solenoid pins; infinite resistance means an open winding
- Check control wire continuity all the way to the module and confirm supply at the connector with the key on
- Wiggle test the harness while watching the meter to catch an intermittent break
- Check the fuse and any relay serving the valve control solenoids
- Repair the wiring or fit a new solenoid, then command the output with the scan tool to confirm current now flows