The P3425: Cylinder 4 Deactivation/Lifter Solenoid Circuit/Open code identifies a malfunction in the circuit of the cylinder 4 deactivation/lifter solenoid in vehicles equipped with active fuel management systems. This system deactivates certain cylinders under specific driving conditions to improve fuel efficiency. A fault in this system can lead to decreased engine performance and increased fuel consumption.
P3425 quick overview
| Meaning | P3425: Cylinder 4 Deactivation/Lifter Solenoid Circuit/Open |
| Is it serious? | This code indicates an issue with cylinder deactivation which can affect engine performance and fuel efficiency. |
| Possible causes | – Faulty cylinder deactivation solenoid – Wiring issues or poor electrical connections in the deactivation solenoid circuit – Engine using incorrect type of oil – Mechanical problems in the engine, such as faulty lifters – ECM (Engine Control Module) software needing an update |
| How to diagnose? | Inspect Solenoid and Wiring: Check the cylinder 4 deactivation solenoid for damage and examine wiring for any signs of wear or corrosion. Check Oil Type and Quality: Verify the use of correct oil type as inappropriate oil can affect the solenoid function. Perform Electrical Tests: Conduct electrical tests on the deactivation solenoid to ensure proper operation. Update ECM Software: If applicable, update the ECM software to the latest version. Mechanical Inspection: Assess the engine mechanically for issues like faulty lifters, especially if the vehicle has high mileage. |
P3425 Meaning
Code P3425 pops up when there’s a problem with one part of your engine that helps save fuel. This part, called the cylinder 4 deactivation solenoid, turns off some of the engine’s cylinders when they’re not needed, like during cruising. If this part isn’t working right, your engine might not run as smoothly and could use more gas than it should. To fix it, a mechanic might need to check the part itself, the wiring connected to it, or update the car’s computer software.
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How to fix P3425 – learn from mechanics
I looked into P3425 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Chrysler
Vehicle Information: 2007 Chrysler 300 C 5.7L
Issue + Repair History:
- MIL lamp on, vehicle stalled once.
- Codes P3425 and P0520 (Oil Pressure) retrieved, oil gauge showed 0 then 99 lbs.
- All deactivation solenoids replaced, oil pressure sender replaced, alternator checked.
- Customer reported low oil pressure before service.
- New code P3400 (Bank One Lean) after service.
Other OBD2 Codes + Test Results:
Suggestions to Fix Issue:
- Check for possible faults in lifters, oil pressure, or MDS solenoid/wiring.
- Use a pressure transducer to check manifold vacuum and ensure cylinder equality.
- Inspect sub harness and connector for MDS Solenoids for heat damage or shorts.
- Confirm oil pressure with a pressure gauge.
- Evaluate if aftermarket parts, particularly MDS solenoids, are affecting performance.
- Consider resetting adaptive memory in the ECM if applicable.
Final Fix:
- Replaced ECM with a rebuilt unit; the vehicle then performed as expected.
- The key indicator was the functioning of fuel saver mode briefly after a restart.
- Original suspicion was the ECM, confirmed by the vehicle’s response after replacement.
Case #2: Jeep
Vehicle Information: 2007 Jeep Grand Cherokee Limited 5.7L
Issue + Repair History:
- Running on only 4 cylinders with all 4 MDS sensor codes.
- Dealer performed TSB reflash, replaced PCM under emission warranty, and replaced all 4 sensors, but no resolution.
- Hardwiring all 4 sensors by the dealer didn’t help.
- Dealer suggested replacing engine harness for $1900 without guarantee of fix.
- Customer looking for alternative solutions.
Computer Codes & Descriptions:
- P3449: MDS Codes
- P3441: MDS Codes
- P3401: MDS Codes
- P3425: MDS Codes
Suggestions to Fix Issue:
- Check BK/LG Z42 circuit for common ground issues.
- Consider possibility of electrical issues rather than mechanical ones like lifters.
- Disconnect the battery for an hour as a reset after PCM flash.
- Look for wire harness problems, particularly around connector C112 at the left rear of the engine.
Final Fix:
- The issue was resolved by repairing the harness that was previously hardwired.
- Found that the ASD relay was toggling rapidly due to a #2 coil with high secondary resistance.
- Replacing the problematic coil resolved the MDS light issue and the vehicle ran perfectly.
- The original problem was likely related to the ASD relay being affected by the coil issue.
Case #3: Dodge
Vehicle Information: 2008 Dodge Charger R/T 5.7L
Issue + Repair History:
- Runs rough after heat soak or extended idle, particularly in high ambient temperatures.
- All coils and spark plugs (OE) have been replaced.
- Grounds checked and cleaned.
- Regular oil changes with 5w20 oil.
- Considering inspecting wiring to MDS solenoids under the manifold.
Computer Codes & Descriptions:
- P3401: MDS Solenoid 1 Circuit
- P3425: MDS Solenoid 4 Circuit
- P3441: MDS Solenoid 6 Circuit
- P3449: MDS Solenoid 7 Circuit
Suggestions to Fix Issue:
- Reflash PCM, as early HEMI MDS had known issues.
- Check connector at the back of the intake manifold for poor connections.
- Verify ground connection at the back of the driver’s side head.
- Check the common ground for MDS solenoids.
- Ensure the latest PCM flash level is installed.
- Use non-platinum spark plugs.
- Inspect the harness to MDS solenoids for damage or brittleness due to oil exposure.
Final Fix:
- Vehicle was reflashed at the dealer.
- Issue could not be duplicated post-reflash, indicating it was a solution.
Case #4: Chevrolet
Vehicle Information: 2006 Chevrolet Impala SS 5.3L
Issue + Repair History:
- SES light on.
- Emissions 2 fuse under the hood is blown and blows again after a few miles.
- Unplugged all fan and AC relays, fans, and deactivation solenoid wires, but found no visible damage.
- Seeking a starting point for testing.
Computer Codes & Descriptions:
- P0102: MAF
- P0480: Cooling Fan Relay
- P081: Cooling Fan Relay
- P3401, P3425, P3441, P3449: Cylinder Deactivation Solenoid Control Circuit
Suggestions to Fix Issue:
- Check cooling fans for excessive amperage draw.
- Unplug fans and relays sequentially to isolate the issue.
- Consider splitting the circuit and adding a half-rating fuse to two legs.
- Conduct a thorough visual inspection for potential shorts.
- Check farthest components from the fuse first.
- Measure amperage draw of components to identify excessive load.
Final Fix:
- Vehicle sent to the dealer for further diagnosis.
- Specific resolution not provided in the post, but the Emissions 2 fuse was identified as not powering the cooling fan motors but rather the relay control coils, A/C compressor circuit, MAF/IAT assembly, and cylinder deactivation solenoids.
Case #5: Chevrolet
Vehicle Information: 2007 Chevrolet Silverado 1500 WT 5.3L
Issue + Repair History:
- The vehicle runs rough after installing a new (used) engine.
- Exhibits loss of power after a road test.
- Initial diagnosis revealed multiple codes related to cylinder deactivation.
- No pulse on injectors for certain cylinders.
- Vehicle previously parked for a long time without hood and engine.
Related Repair History:
- Installed used engine.
Computer Codes & Descriptions:
- P3401: Cylinder 1 Deactivation Valve Circuit
- P3425: Cylinder 4 Deactivation Valve Circuit
- P3441: Cylinder 6 Deactivation Solenoid Circuit
- P3449: Cylinder 7 Deactivation Solenoid Circuit
Suggestions to Fix Issue:
- Ensure the replacement engine matches the vehicle’s original specifications, particularly for the Displacement on Demand (DoD) system.
- Check electrical connections, particularly those related to the cylinder deactivation system.
- Consider reprogramming the ECM to match the engine if it is different from the original.
- Inspect for wiring harness issues and proper solenoid function.
Final Fix:
- After reevaluation, it was determined that the installed engine did not have the Displacement on Demand (DoD) system.
- The vehicle was fixed by installing an engine with the AFM (Active Fuel Management) system compatible with the original vehicle setup.
How to diagnose P3425
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Advice | Brief Description of Diagnostic Step |
|---|---|
| Check Engine Compatibility | Ensure the engine installed is compatible with the vehicle’s system, especially concerning cylinder deactivation. |
| Inspect Wiring Harness | Closely examine the wiring harness for damage, shorts, or corrosion, particularly around the MDS solenoids. |
| Test MDS Solenoids | Perform tests on the Multi-Displacement System (MDS) solenoids to check their functionality and resistance. |
| Reprogram/Update ECM | Consider reprogramming or updating the Engine Control Module (ECM) to ensure it matches the engine setup. |
| Check Electrical Connections | Ensure all electrical connections, especially to the MDS solenoids, are secure and free of corrosion. |
| Examine Cylinder Deactivation System | Thoroughly inspect the cylinder deactivation system for any mechanical or electrical faults. |
| Verify Proper Grounding | Check the grounding points related to the MDS system to ensure they are properly connected and intact. |
| Use OEM Parts | Prefer original equipment manufacturer (OEM) parts for replacements, especially for components like lifters and solenoids. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko