By iCarsoft Official Store Technical Team, Automotive Diagnostics Editors · Updated September 2, 2026 · OEM technical references checked
Quick Answer
The P3425 code means cylinder 4 deactivation/intake valve control circuit/open. It does not prove cylinder 3 is affected, the cylinder 4 solenoid alone failed, or a misfire proves an internal valve-train fault. Save the scan, identify the exact architecture, and test the physical and electrical paths before selecting a repair.
What Does the P3425 Code Mean?
P3425 is standardized as Cylinder 4 Deactivation/Intake Valve Control Circuit/Open. It names a monitored result, not a guaranteed failed part. The reporting module, suffix and companion faults determine the relevant test branch.
Cylinder-deactivation systems can use oil pressure, control solenoids and special lifter or valve hardware. Cylinder numbering, bank assignment, oil circuit layout and whether the solenoid is separately serviceable must come from the VIN-specific engine information.
Read each suffix as its exact monitor classification, not a universal physical direction. Confirm the designation, units, signal source and test state before comparing scan data with an external measurement.
Stellantis TSB 18-002-25 lists P3425 as Cylinder 4 Deactivation Control Circuit on a specified 2023 Ram 1500 5.7L Hemi application and includes a PCM software update. That source confirms the cylinder number and system but does not prove software is the repair elsewhere.
Separate P3425 from adjacent fault families
| Code | General description | Key distinction |
|---|---|---|
| P3425 | Cylinder 4 deactivation/intake-valve control circuit/open | Electrical/open result for cylinder 4 control. |
| P3426 | Cylinder 4 deactivation control performance | Performance result rather than circuit/open. |
| P3427 | Cylinder 4 deactivation control circuit low | Low electrical classification. |
| P3428 | Cylinder 4 deactivation control circuit high | High electrical classification. |
Record the complete P3425 description. The suffix, reporting module and companion faults can change the diagnostic path. Current manufacturer evidence governs when the queue wording conflicts.
P3425 Symptoms and Likely Causes
P3425 symptoms depend on fault status and the fallback strategy. Record what the driver and modules reported. A symptom list is not a parts list.
The controller may inhibit deactivation and keep all cylinders active.
Oil, ignition, fueling and mechanical faults can overlap; save companion codes.
Deactivation may be disabled, but driving conditions dominate consumption.
Stop and verify lubrication before electrical tests continue.
Practical cause-checking order
- Accessible connection: Loose connector, damaged wiring or poor terminal contact at the cylinder 4 control.
- Circuit or shared path: Incorrect oil level, viscosity, pressure or contamination affecting the deactivation hydraulic path.
- Supporting system: A control solenoid that fails the OEM electrical and functional test.
- Named component: Internal lifter/valve-train or oil-passage problem supported by mechanical evidence.
- Controller or software: Applicable PCM calibration or driver fault after oil, mechanical and circuit paths pass.
Did P3425 appear after recent oil, valve-train, intake, cylinder-head, battery or software work? Recheck disturbed connectors, grounds, hoses, fluids, part numbers and setup steps for the cylinder 4 deactivation/intake-valve control electrical path. Record battery and software history; a post-repair code does not prove the new part is defective.
How Serious Is P3425, and Can You Drive?
Arrange diagnosis promptly. When the warning is steady, operation remains normal and the owner's manual permits it, a short light-load trip to a repair facility may be reasonable. Avoid demanding use until the cylinder 4 deactivation/intake-valve control electrical path is understood. P3425 does not provide a universally safe distance.
Record temperature, load, speed, start state and recent service. Do not reproduce a severe symptom on public roads; another warning can make the situation more urgent.
Stop and arrange a tow if an oil-pressure warning appears, knocking or severe ticking starts, the MIL flashes, the engine misfires heavily or power loss is unsafe.
Valve-train parts can move without warning and hot oil is hazardous. Disable starting and verify oil pressure with the approved procedure.
How to Diagnose P3425 in the Right Order
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Save the complete fault record
Scan before clearing. Save P3425 wording, suffix, reporting module, status, freeze frame, companion codes, supply voltage and available data for the cylinder 4 deactivation/intake-valve control electrical path. Record failure order, recent repairs and restart behavior for later comparison.
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Identify the VIN-specific monitor and architecture
Use the VIN, engine, transmission and equipment codes to obtain the current wiring diagram, connector views, monitor description and bulletins. Cylinder-deactivation systems can use oil pressure, control solenoids and special lifter or valve hardware. Cylinder numbering, bank assignment, oil circuit layout and whether the solenoid is separately serviceable must come from the VIN-specific engine information. Confirm software identifiers and service-action eligibility directly; a bulletin for one application does not establish coverage for another.
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Inspect the accessible physical path
Follow the safety procedure, then inspect connectors, locks, seals, terminals, clips and harness routing for the cylinder 4 deactivation/intake-valve control electrical path. Look for heat, abrasion, fluid entry, corrosion, tension and unsuitable prior repairs. Check the supporting mechanical, air, exhaust, fluid or vacuum path named in the service information. Photograph evidence before correcting it.
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Prove circuits and physical conditions
Use the oil-pressure test equipment, multimeter, scope and mechanical inspection tools specified for the engine as the exact procedure requires. Prove feeds, grounds and references under the specified load, then test signal or control integrity at the correct states. Isolate components before resistance tests. Never bridge a controller pin to battery or ground, and do not substitute a continuity beep for a load, pressure or waveform test.
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Compare supported command and response
Compare supported deactivation command, cylinder state, misfire and oil-control data, but confirm actual pressure and circuit load with external instruments. Compare scan evidence with the external measurement and companion faults. A command does not prove physical movement, pressure, current, temperature or torque. A missing PID or active test is a coverage limitation, not evidence that the vehicle component failed. Stop any test if operation becomes unsafe.
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Choose the supported repair and setup
Repair the failed path and correct the reason for damage. Confirm part application, programming authority and any relearn. Consider a controller only after its powers, grounds, inputs, outputs and service information pass.
Specifications are vehicle-specific. There is no universal voltage, resistance, current, pressure, waveform, timing, temperature, percentage, learned value or drive cycle for P3425. Test state, connector location and system design change what a valid value means. Use only specifications for the exact VIN and do not transfer the OEM example in this article to another application.
P3425 Repairs and Typical Costs
The correct P3425 repair follows the failed test. Wiring, a physical repair, a proven component, software and controller work are different outcomes. Do not replace an assembly from the generic code alone.
After installation, recheck connector seating, harness clearance, fluid or mechanical setup and every required learn. If an OEM bulletin appears relevant, document vehicle eligibility, installed calibration and prescribed action. The existence of the bulletin in the references does not promise warranty, free repair or a software cure for other vehicles.
| Possible path | Current US estimate |
|---|---|
| Repair the cylinder 4 connector, harness, feed or driver path | VIN-specific quote |
| Correct a proven oil-level, oil-quality, pressure or passage problem | VIN-specific quote |
| Replace a tested deactivation solenoid or permitted valve-train component | VIN-specific quote |
| Perform applicable programming/setup only after the physical and circuit diagnosis | VIN-specific quote |
There is no single national P3425 repair price because these rows are alternative outcomes. Ask for an itemized estimate showing diagnostic time, parts, labor, fluids, programming access and verification. Location, taxes, related damage and warranty eligibility change the total. Do not add the rows together or authorize an assembly without the supporting failed test.
Using iCarsoft CR Max P for P3425
On a supported vehicle, iCarsoft CR Max P can retrieve accessible module faults, save available freeze frame, display ECU-provided live data and create a diagnostic report. For P3425, preserve the original evidence and compare related modules before clearing an erasable record.
Preserve the cylinder 4 deactivation/intake-valve control electrical path evidence
iCarsoft CR Max P
Review supported codes and relevant live data together. Confirm the exact VIN, controller access, PIDs and any requested active test with iCarsoft before purchase; generic product capabilities do not guarantee a P3425-specific function.
Check current CR Max P price and availabilityCheck CR Max P compatibility by VINThe official product page describes full-system diagnosis, available freeze frame/live data, reports, topology and supported bidirectional functions; every function remains vehicle, ECU and software dependent. Follow OEM prerequisites and stop for abnormal operation. A topology, coding or programming feature does not by itself supply the manufacturer file, subscription, authorization or procedure required by an OEM bulletin.
Know the measurement boundary. The scanner reports information supplied by the vehicle. It does not directly prove terminal tension, circuit load capacity, leakage, pressure, temperature, mechanical travel or internal condition in the cylinder 4 deactivation/intake-valve control electrical path. It also cannot replace the oil-pressure test equipment, multimeter, scope and mechanical inspection tools specified for the engine when the OEM procedure requires them. Interpret commanded and reported values alongside measured evidence.
Verify the P3425 Repair
After repair, verify connectors, harness clearance, setup and controller supply. Save post-repair findings, then clear only erasable records through the approved procedure. Battery disconnection is not a repair.
Run the manufacturer's applicable verification conditions in a safe workshop or route. Compare the original operating state with current data for the cylinder 4 deactivation/intake-valve control electrical path, and check current and pending faults in related modules. One clean start or idle period does not prove that every conditional monitor has completed.
If P3425 returns, compare its suffix, status, failure order and operating conditions with the saved baseline before replacing another part. Revisit the failed branch and inspect anything disturbed. Keep mechanical repair, monitor completion, readiness and local inspection eligibility as separate outcomes.
A permanent P3425 can remain immediately after a successful repair. If the vehicle stores it as a permanent DTC, a scan tool or battery disconnect cannot erase it. Once current and pending faults are absent, the OBD system removes the permanent record only after the applicable monitor reruns and passes.
Related Cylinder 4 Deactivation/Intake-Valve Control Electrical Path Code Guides
P3425 Frequently Asked Questions
Does P3425 mean the named component is bad?
No. P3425 describes cylinder 4 deactivation/intake valve control circuit/open, not a confirmed part. It also does not prove cylinder 3 is affected, the cylinder 4 solenoid alone failed, or a misfire proves an internal valve-train fault. Test accessible wiring, supplies, grounds and supporting physical conditions, then follow the exact monitor tree. Replace a component only when its branch fails or an applicable OEM action specifically supports it.
What should I check first for P3425?
Save every module's codes and freeze frame before clearing. Confirm the full definition, suffix and VIN architecture. Then inspect recent oil, valve-train, intake, cylinder-head, battery or software work, connectors and shared supplies. Those facts determine whether the next test needs the oil-pressure test equipment, multimeter, scope and mechanical inspection tools specified for the engine or a manufacturer-specific functional procedure.
Can I drive with the P3425 code?
Only consider a short light-load trip when operation is normal and the owner's manual permits it. Stop if an oil-pressure warning appears, knocking or severe ticking starts, the MIL flashes, the engine misfires heavily or power loss is unsafe. The code number cannot establish a safe mileage allowance, and another warning can make the situation more urgent.
Why did P3425 return after a part was replaced?
The original circuit or supporting-system fault may remain, the part or setup may be wrong, or the first diagnosis may have confused a monitored result with a failed component. Compare the new failure conditions with the saved record and recheck every disturbed connection before buying another part.
How much does a P3425 repair cost?
A VIN-specific estimate is required because diagnosis may lead to wiring, a supporting physical repair, a verified component, software or a controller. Ask which failed test supports the quote and whether diagnosis, taxes, setup and post-repair verification are included.
Can CR Max P diagnose and clear P3425?
On a supported vehicle, CR Max P can organize available faults, freeze frame, live data and reports, and can clear erasable records after repair. Confirm exact ECU coverage. It cannot force-clear a permanent DTC or replace physical measurements for the cylinder 4 deactivation/intake-valve control electrical path.
The iCarsoft Official Store Technical Team maintains the store's fault-code library. This guide organizes published manufacturer evidence and verified product information; it does not document a hands-on test of a particular vehicle or claim an individual engineer's review.
Technical and cost references
- Stellantis TSB 18-002-25, January 25, 2025. Lists P3425 as Cylinder 4 Deactivation Control Circuit on the specified Ram 1500 5.7L Hemi application.
- California Bureau of Automotive Repair — On-Board Diagnostic Test Reference. Permanent DTCs are removed by the vehicle after applicable verification, not by a scan-tool erase command.
Product information: Official iCarsoft CR Max P page.
Editorial note: General diagnostic education, not a substitute for the owner's manual, current VIN-specific service information or professional inspection. Test limits, procedures, coverage and costs vary. Related articles provide context; apply only the specifications and repair procedures that match the vehicle. No universal failure rate, repair price or outcome is implied.
