P3425: Cylinder 4 Deactivation/Intake Valve Control Circuit/Open

Cylinder 4 is one of the four cylinders that classic V8 cylinder deactivation shuts off, together with 1, 6 and 7, both at GM (Active Fuel Management) and on the Chrysler 5.7 L Hemi with MDS. That makes P3425 one of the best documented codes in this range. GM's 2019 tables for the L84 and L86 flag an open when the off-state output shows more than 200 kohm, 20 of 25 samples, Type B. Chrysler lists it as Cylinder 4 Deactivation Control Circuit; a STAR case describes the driver-side exhaust manifold heat shield wearing through the solenoid harness and asks for at least 15 mm clearance. P3427 and P3428 cover shorts on the same circuit.

Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

Cylinder 4 is numbered according to the manufacturer: check your engine's manual before working on it.

Symptoms

Check engine lamp on
Engine stays in eight-cylinder mode
Further circuit codes for cylinders 1, 6 and 7 if the shared harness is damaged

Most likely causes

Solenoid harness chafed through by the exhaust manifold heat shield (5.7 L Hemi)
Open coil in the cylinder 4 deactivation solenoid
Corroded or loose solenoid connector
Control module software needing an update (Chrysler TSB 18-002-25)

What to check, in order

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

Check the oil level and condition before anything else
Check the continuity of the wire between the component and the control module.
Check the solenoid valve's connector
Compare commanded and actual angles in live data
Test the solenoid valve and its filter, if it has one
Check the engine timing if there is chain noise

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P3425 means

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

Frequently asked questions

Can I keep driving with code P3425?

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

What causes code P3425?

The most common causes are: solenoid harness chafed through by the exhaust manifold heat shield (5.7 L Hemi); open coil in the cylinder 4 deactivation solenoid; corroded or loose solenoid connector.

Related codes

Sources

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.