HomeTrouble CodesP3424

P3424 — Cylinder 3 Exhaust Valve Control Circuit High

Manufacturer-specificPowertrain (engine & transmission)

OBD-II code P3424 indicates the engine control module (PCM/ECM) has detected a high-voltage condition in the exhaust valve control circuit for cylinder 3. On most engines this refers to the exhaust-side variable valve timing (VVT) solenoid or cam phaser actuator circuit, and a 'High' reading typically points to an open circuit, a short to voltage, or a solenoid/actuator that has failed in a way the PCM interprets as abnormally high signal voltage.

Symptoms

What causes it — most likely first

1. Failed exhaust VVT/cam phaser solenoid for cylinder 3

The exhaust valve control solenoid is the component most often at fault. Internal opens, shorts, or wear can cause the PCM to read a high circuit voltage.

2. Wiring or connector problems in the exhaust control circuit

An open wire, chafed insulation, loose pin, or corroded connector between the solenoid and the PCM is a very common cause of a high-voltage reading.

3. Low, dirty, or degraded engine oil

VVT and cam phaser systems depend on clean oil at proper pressure. Sludge, low level, or wrong viscosity can prevent the actuator from operating, indirectly triggering circuit fault codes.

4. Stuck or worn exhaust camshaft phaser / actuator

A mechanically failed cam phaser may not move the camshaft as commanded, and the resulting position/voltage feedback can set this code.

5. Faulty engine control module (PCM/ECM)

The PCM itself is an uncommon cause, but an internal driver issue or software problem can occasionally produce this code. It should only be considered after the solenoid, wiring, oil, and phaser have been ruled out.

How it's diagnosed

  1. Verify the code with a scan tool and record any related VVT, cam, or oil-pressure codes and freeze-frame data.
  2. Perform a visual inspection of the cylinder 3 exhaust VVT solenoid connector and harness, looking for chafing, corrosion, oil contamination, or bent pins.
  3. Check engine oil level, condition, and viscosity; correct any oil issues and re-evaluate before replacing parts.
  4. Measure resistance and reference-voltage behavior of the exhaust VVT solenoid with the connector disconnected, comparing to manufacturer specification.
  5. Back-probe the control circuit at the PCM connector to check for short to power, open, or excessive voltage that the solenoid itself is not responsible for.
  6. If the solenoid, wiring, and oil are good, evaluate exhaust cam phaser mechanical function and timing correlation before suspecting the PCM.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is replacing the PCM the fix for P3424?

No. In the vast majority of cases P3424 is caused by the cylinder 3 exhaust VVT solenoid, its wiring, or oil-related issues — not the engine computer. The PCM should only be considered after those other causes have been tested and eliminated.

Can I keep driving with P3424?

Short trips are usually possible, but the engine may run rough, have reduced power, use more fuel, and produce higher emissions. Prolonged driving with impaired VVT operation can stress other valvetrain components, so diagnosis should not be delayed.

What does 'High' actually mean in this code?

It means the PCM measured a voltage in the exhaust valve control circuit that was above the expected range. This is most often the result of an open circuit or a short to power, or a solenoid that has failed in a way that pulls the signal high.

Does this code only affect cylinder 3?

The code is cylinder-specific, so it points to the exhaust valve control components associated with cylinder 3 (solenoid, wiring, or phaser on that cylinder). Other cylinders have their own dedicated codes if they develop similar faults.