AutoCodes – Jeep – P3420 Jeep

P3420 Jeep Code - Cylinder 3 Deactivation Control Circuit High

Quick Answer

When all the criteria has been met,power is supplied to each Multi-Displacement System (MDS) Solenoid when engine is making a transition from 8 cylinder mode to 4 cylinder mode. Common causes include Low oil pressure, Restricted oil passage, Engine mechanical condition. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P3420 Jeep indicates Cylinder 3 Deactivation Control Circuit High.
Common causes: Common causes include Low oil pressure, Restricted oil passage, Engine mechanical condition.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 1,311

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 05, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P3420 Jeep Description

When all the criteria has been met,power is supplied to each Multi-Displacement System (MDS) Solenoid when engine is making a transition from 8 cylinder mode to 4 cylinder mode. By actuating the solenoid, oil pressure is raised to the pair of lifter that coincide with each particular solenoid. The oil pressure pushes in the locking pins that allows the lifter to collapse, decoupling the valves and camshafts.

OBDII Code P3420 Jeep - Cylinder 3 Deactivation Control Circuit High - AutoCodes.com — P3420 Jeep Code - Cylinder 3 Deactivation Control Circuit High

What does this mean?

What are the Possible Causes of the DTC P3420 Jeep?

Low oil pressure
Restricted oil passage
Engine mechanical condition
Faulty Multiple Displacement System (MDS) Solenoid
Multiple Displacement System (MDS) Solenoid harness is open or shorted
Multiple Displacement System (MDS) Solenoid circuit poor electrical connection

How to Fix the DTC P3420 Jeep?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Although in some cases changing the engine oil may fix the problem, usually the Multi Displacement System Solenoid may need to replaced.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P3420 Jeep code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P3420 Jeep Code

1. What does the OBDII code P3420 mean on a Jeep?

P3420 indicates an issue with the Cylinder 3 Deactivation Control Circuit High, meaning the signal voltage is outside the expected range.

2. What are the symptoms of code P3420 on a Jeep?

Common symptoms include reduced engine performance, misfires, rough idle, decreased fuel efficiency, and the check engine light turning on.

3. What causes the P3420 code to appear?

Possible causes include a faulty cylinder deactivation solenoid, damaged wiring or connectors, low oil pressure, or an issue with the powertrain control module (PCM).

4. Is it safe to drive with a P3420 code on a Jeep?

While the vehicle may still be drivable, ignoring the code could lead to further engine damage or reduced fuel efficiency. Prompt diagnosis and repair are recommended.

5. How do I diagnose the P3420 code on my Jeep?

Start by inspecting the wiring and connectors for Cylinder 3â€™s deactivation solenoid, then test the solenoid for proper function. Check for low oil pressure or PCM-related issues if needed.

6. Can low oil pressure cause the P3420 code?

Yes, low oil pressure can prevent the cylinder deactivation system from functioning correctly, triggering the P3420 code.

7. How can I fix the P3420 code on my Jeep?

Repair may involve replacing a faulty cylinder deactivation solenoid, repairing damaged wiring or connectors, or addressing oil pressure issues. In rare cases, the PCM may need reprogramming or replacement.

8. How much does it cost to fix the P3420 code?

The repair cost varies depending on the cause, but replacing a cylinder deactivation solenoid typically costs $150â€“$300, including parts and labor.

9. Can a dirty oil filter cause the P3420 code?

Yes, a clogged oil filter can restrict oil flow, leading to insufficient pressure for the cylinder deactivation system and triggering the code.

10. Will clearing the P3420 code solve the problem?

Clearing the code without addressing the underlying issue will only provide a temporary fix, and the code is likely to return. Proper diagnosis and repair are necessary.