2012 Jeep Wrangler Engine Problems

The engine's cylinder head/valve train has failed internally, allowing combustion gases to enter the cooling system — confirmed via a chemical block test performed by a master automotive technician on November 29, 2024, which verified combustion gases present in the coolant. This is a widely documented defect on this engine and model year, related to valve seat erosion in the cylinder head. Symptoms first appeared in June 2018 as an unusual higher-pitched, stressed sound from the engine. Over time this progressed to recurring, confirmed misfires on cylinders 1, 2, 3, and 5 (diagnostic codes P0300, P0301, P0302, P0303, P0305) and a mixture control fault (P219B). The check engine light has intermittently stayed illuminated for months at a time, then gone off for extended periods while the same fault codes remain stored and confirmed by a diagnostic scanner — currently the light is off but the codes persist. The vehicle frequently runs rough enough that the engine must be turned off and restarted to temporarily return to closer-to-normal operation. Noticeable vibration is felt during much of this pattern. Spark plugs, ignition coils, oxygen sensors, and the PCV valve have all been inspected/replaced and ruled out as the cause on multiple occasions over more than a year, isolating the cause to the cylinder head itself. This creates a driveability and potential stalling/hesitation risk, though no crash, injury, or fire has occurred to date. The vehicle has not been formally inspected by the manufacturer, police, or an insurance representative. The affected component remains in the vehicle and is available for inspection upon request.

NHTSA ID

11748922

Incident

Nov 29, 2024

The contact owns a 2012 Jeep Wrangler. The contact stated that while driving at 20 MPH, the check engine warning light illuminated. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The vehicle was taken to an independent mechanic, where a scan was completed, and diagnostic trouble codes for the Emissions, engine misfire, timing chain, and crank position sensor failures were displayed. The manufacturer was not contacted. The failure mileage was approximately 71,756.

NHTSA ID

11728445

Incident

Mar 26, 2026

Mileage

71,756 mi

My complaint is that I was sold a dangerously defective vehicle with a known, unrepaired “stop driving” airbag safety recall, was not warned about the deadly risk, and am now being told to move and tow the car in direct contradiction to official safety instructions. ### Factual background - The vehicle I purchased has a Takata‑type airbag safety recall that carries a formal “do not drive” or “stop driving” warning because the airbag can explode and kill or severely injure occupants, even in a minor crash.[1][2][3][4] - Federal safety authorities have confirmed that at least 28–29 people in the United States have been killed and more than 400 injured by exploding Takata airbag inflators.[3][4][5][1] - I received the recall notice about two months ago, but I was told the repair parts were back‑ordered, which delayed fixing the deadly defect through no fault of my own.[1][3] - During this delay, the vehicle’s battery became completely dead, and I am now being told by the recall and towing company that I must make sure the car is taken out of the garage, which would require entering and moving a vehicle I have been legally and explicitly told not to drive. ### Legal and safety concerns - Official guidance from the National Highway Traffic Safety Administration (NHTSA) and the manufacturer is that vehicles under this Takata “do not drive” recall must not be driven at all until the defective airbag is replaced, because even a minor collision can cause the inflator to explode and send metal shrapnel into the cabin.[2][4][3][1] - The instruction to move or drive the car out of the garage conflicts with this clear safety warning and effectively asks me to assume a risk that has already caused multiple deaths and serious injuries nationwide.[4][5][2][3][1] - Federal law prohibits franchised dealers from selling new vehicles with unrepaired safety recalls, and legal experts warn that selling used vehicles with undisclosed safety defects can expose sellers and dealers to

NHTSA ID

11727336

Incident

Jan 20, 2026

The vehicle exhibits a persistent valvetrain ticking noise associated with the rocker/lifter/cam components of the 3.6L Pentastar V6. The engine makes a rhythmic metallic tapping at idle and during acceleration. The noise has progressively worsened, leading to rough idle and occasional misfires. This issue is documented in multiple Stellantis technical service bulletins (e.g., TSB 09-015-24 and TSB 09-011-25) which attribute the noise to hydraulic lash adjuster and cam/rocker wear. If unaddressed, the failure can cause camshaft damage, metal debris contamination, loss of power and potential engine stall, posing a safety risk. The vehicle is available for inspection. The problem has been confirmed by independent mechanics who recommend replacement of the rocker arms, lifters and camshaft to prevent catastrophic engine failure.

NHTSA ID

11696485

Incident

Oct 29, 2025

The vehicle exhibits a persistent valvetrain ticking noise associated with the rocker/lifter/cam components of the 3.6L Pentastar V6. The engine makes a rhythmic metallic tapping at idle and during acceleration. The noise has progressively worsened, leading to rough idle and occasional misfires. This issue is documented in multiple Stellantis technical service bulletins (e.g., TSB 09-015-24 and TSB 09-011-25) which attribute the noise to hydraulic lash adjuster and cam/rocker wear. If unaddressed, the failure can cause camshaft damage, metal debris contamination, loss of power and potential engine stall, posing a safety risk. The vehicle is available for inspection. The problem has been confirmed by independent mechanics who recommend replacement of the rocker arms, lifters and camshaft to prevent catastrophic engine failure.

NHTSA ID

11690582

Incident

Jul 1, 2025

Timing chain and misfire bank 1 and bank 2 crank shaft and crank sensor issues.

NHTSA ID

11684159

Incident

Aug 10, 2025

I am reporting a persistent and safety-relevant defect in my 2012 Jeep Wrangler with the 3.6L Pentastar engine. The vehicle is experiencing misfires on multiple cylinders, especially cylinders 1 and 5, triggering codes P0300, P0301, and P0305. These misfires result in loss of power, hesitation, and rough idle, creating serious safety concerns during acceleration or highway driving. Despite replacing spark plugs, ignition coils, the crankshaft position sensor, purge valve, and both oxygen sensors, the problem continues. The vehicle has just 83,000 miles and is currently at a certified third-party repair facility. Multiple mechanics believe the issue stems from known defects in the left (Bank 1) cylinder head or valve train components—an issue Chrysler previously acknowledged via TSBs and a 10yr/150k mile extended warranty on select VINs. I contacted Jeep Cares and requested goodwill support, but they refused to even discuss the issue because my Jeep is not at a dealership. This leaves owners like me with limited, expensive options despite being affected by a well-documented defect. Jeep forums and independent shops have seen widespread misfire problems on early 3.6L Pentastar engines, especially 2012-2013 models. I urge NHTSA to investigate this pattern of failure. The misfires impact driveability and safety, and the manufacturer has not offered sufficient resolution or consistent support to affected customers. I’m happy to provide additional information, documentation, or diagnostics.

NHTSA ID

11665284

Incident

May 11, 2025

Engine spontaneously caught fire. It had been parked for hours before it happened. Everything under the hood was totaled

NHTSA ID

11639631

Incident

Jan 28, 2025

The contact owns a 2012 Jeep Wrangler. The contact stated that while operating the vehicle the ABS, Traction Control and check engine warning lights had remained illuminated. The contact indicated that while pressing the brake pedal to stop, the brake pedal extended to the floor causing the braking distance to become extended. The vehicle was taken to the local dealer who diagnosed that the ABS module was faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure but no assistance was offered. The failure mileage was 55,000.

NHTSA ID

11619915

Incident

Oct 15, 2023

Mileage

55,000 mi

In my 2012 Jeep I had to replace the engine and catalytic converters. The engine number 3 cylinder failed due to excessive ware causing lower compression. After the engine (long block) was replaced, one of the cylinders was miss firing. This miss firing was traced to micro cracks in the plastic/composite intake manifold (original and not part of the engine replacement). Because these micro cracks changed the fuel air ratio on specific cylinders by leaning out the cylinders near the cracks this lean mixture would cause the affected cylinders to run hot that would lead to both the excessive ware on the one cylinder and would comprise the catalytic converters. Because this change in fuel air mixture was caused by the intake manifold and Jeep does not have any inspection requirements or methods for this item and even after the Jeep Dealer did a full diagnosis using their factory specified equipment the issue with the manifold was not found. My local AMMCO shop found the cracking in the manifold that was the route cause of the problem.

NHTSA ID

11563525

Incident

Jul 31, 2023

Jeep Wrangler 3.6 liter 90k miles lifter making loud noise. Seems you had a recall about this on the 2012 and guess I missed out

NHTSA ID

11562348

Incident

Aug 24, 2023

6 days after an oil change, the temp gauge while driving went from cool to hot in under a mile and the engine temp light came on. There was coolant all over the underside of the car it was near catastrophic. I had to have it towed to the dealership for repairs. The faulty part was the oil filter adapter it was cracked by over tightening of the oil filter.

NHTSA ID

11549495

Incident

Sep 7, 2023

Engine Stalls Randomly while Driving. Will crank over several times and over approx 10-15 min. of cranking(Say every 3-5min) vehicle will and will restart. No check engine lights and no warning. The loss of power can be dangerous since brake and steering assist require engine to be running. Vehicle will be fine for several days local commute and problem will recur without warning, usually on longer commute. Vehicle is unsafe and unpredictable.

NHTSA ID

11515380

Incident

Apr 4, 2023

CAM SENSOR FAILED. CHECK ENGINE LIGHT AND TRACTION CONTROL LIGHT APPEARED. REPLACED AND SAME PROBLEMS OCCURRED. MAY BE WIRING OR CAM/ROCKER ISSUES.

NHTSA ID

11496427

Incident

Dec 5, 2022

The contact owns a 2012 Jeep Wrangler. The contact stated while starting the vehicle, there was an abnormal burning odor around the vehicle. The contact stated while driving 45 MPH and other various speeds the burning odor was still present. The check engine warning light illuminated with the temperature gauge rising from normal to hot. An audible alarm was heard during the failure. The vehicle was driven to the residence and then towed to a dealer. The vehicle was diagnosed and determined that the radiator needed to be replaced. The contact had the vehicle towed to an independent mechanic who determined that coolant was leaking into the cylinder head. The vehicle had not been repaired. The manufacturer had been informed of the failure. The failure mileage was approximately 60,000.

NHTSA ID

11494026

Incident

Jan 14, 2018

Mileage

60,000 mi

While driving the car randomly stalls. I lose power steering and braking. The car will not restart. This issue has been recorded by the dealer. The vehicle was last inspected on July 5th. I have been issued a Jeep Care case manager, case # 82963828. There are no warnings, while driving makes a left-hand turn the car just stalls!

NHTSA ID

11473598

Incident

Jul 12, 2022

While driving making a turn, shifting from 1st to 2nd gear, and vehicle stalls losing all power. I had a crank no-start scenario! The vehicle has been to the dealer multiple times and the issue can not be duplicated. The vehicle has been inspected multiple times and there are no known issues. No-fault codes are thrown. I was able to cost to a safe location, and wait. after 3-5 min the vehicle restarted.

NHTSA ID

11472279

Incident

Jul 4, 2022

While driving making a turn, shifting from 1st to 2nd gear, and vehicle stalls losing all power. I had a crank no-start scenario! The vehicle has been to the deal multiple times and the issue can not be duplicated. The vehicle has been inspected multiple times and there are no known issues. No-fault codes are thrown. I was able to cost to a safe location, and wait. after 3-5 min the vehicle restarted.

NHTSA ID

11472278

Incident

Jul 1, 2022

While driving making a turn, shifting from 1st to 2nd gear, and vehicle stalls losing all power. The vehicle has been to the deal multiple times and the issue can not be duplicated. The vehicle has been inspected multiple times and there are no known issues. No-fault codes are thrown. I stalled in the middle of a busy intersection, with my children in the car. I had to push the vehicle to safety!

NHTSA ID

11472276

Incident

Jul 1, 2022

Starting out at a stop sign. engaging the clutch to start moving, while shifting into 2nd gear while turning the vehicle stalls. Losing all power steer and brakes. I try to re-start the car i get a crank no-start scenario. Wait 3-5 min, retry starting the vehicle starts.

NHTSA ID

11472274

Incident

Jun 29, 2022

Starting out at a stop light, engaging the clutch to start moving, I depressed the clutch to shift into second gear while making a turn, the vehicle stalls, losing all power.

NHTSA ID

11472273

Incident

Jun 27, 2022

I was driving on the highway and the engine caught fire. I’ve been looking for an engine to rebuild and all of them had previously been on fire. I believe the engine is defective for the jeeps that year, make and model.

NHTSA ID

11471058

Incident

Apr 21, 2021

While driving the car stalled. Loss of power steering and braking. I was able to coast to a safe location. I tried to restart, but Crank- No Start.

NHTSA ID

11466515

Incident

May 28, 2022

Random Stalling while driving, making a left-hand turn. While entering an intersection, the vehicle stalled losing all power. Was able to coast to a safe spot. Waited 15 min, the vehicle started. No check engine light.

NHTSA ID

11463049

Incident

Apr 6, 2022

While crossing an intersection the vehicle stalled for no reason. No Codes were posted. Crank No Start, waited 10 min, and the vehicle started. Drove to the dealer to resolve. Dealer has no known reason for stalling while driving

NHTSA ID

11463048

Incident

Apr 18, 2022