What is the 2000-2006 Jeep Wrangler Front Frame Rust and Control Arm Bracket Corrosion?

Rust-through of the TJ frame, especially near the lower control arm mounts, skid plate area, and rear trailing arm sections, is one of the most serious age-related Wrangler problems. In rust-belt states, owners report perforation severe enough to affect suspension mounting integr… Repairs typically run $800-$5,000. Severity: high.

What is the 1994-2006 Jeep Wrangler Body Tub, Floor Pan & Body-Mount Rust (Torque Box Corrosion)?

Distinct from frame corrosion, the steel body tub rusts from the inside out on older Wranglers, especially in salt regions. The spot-welded body-mount channels ('torque boxes') under the floor, the floor-pan seams, and the rocker areas trap moisture and rot around the three body… Repairs typically run $400-$3,500. Severity: high.

What is the 1997-2006 Jeep Wrangler 4.0L Crankshaft Position Sensor Thermal Failure — Random Stalling & Hot No-Start?

The crankshaft position sensor (CPS) on the 4.0L (and 2.5L) inline engines mounts on the transmission bellhousing and is exposed to severe heat soak. As it ages it develops intermittent thermal failure: the engine stalls without warning once hot, then refuses to restart until it… Repairs typically run $60-$250. Severity: high.

What is the 1994-2006 Jeep Wrangler Dana 35 Rear Axle Shaft C-Clip Failure ("Grenade")?

The Dana 35 rear axle fitted to most non-Rubicon YJ/TJ Wranglers uses a C-clip design: each semi-float axle shaft is retained inside the housing only by a C-clip seated in the differential. If a shaft snaps — common with 33-inch-plus tires, a locker, or aggressive trail use — the… Repairs typically run $300-$2,200. Severity: high.

What is the 2000-2006 Jeep Wrangler Catalytic Converter Failure and Pre-Cat Efficiency Codes on 4.0L?

TJ Wranglers with the 4.0L frequently develop catalytic converter deterioration, especially on higher-mileage vehicles and 2000-2006 emissions configurations using multiple converters/pre-cats. Owners commonly report a check-engine light with catalyst-efficiency codes, sulfur sme… Repairs typically run $600-$1,800. Severity: medium.

What is the 2000-2006 Jeep Wrangler Ignition Coil Rail Failure Causing Misfire on 4.0L?

The 4.0L coil-rail ignition system used on TJ Wranglers is known to develop internal failures that cause intermittent or persistent misfires. Owners report rough idle, hesitation, flashing check-engine lights, and cylinder-specific misfire codes, often after moisture intrusion, a… Repairs typically run $180-$500. Severity: medium.

What is the 1997-2006 Jeep Wrangler Heater Core Leak — Coolant Smell & Fogged Windshield?

The heater core inside the dash-mounted HVAC box develops leaks on high-mileage Wranglers, releasing a sweet coolant smell in the cabin, an oily film that fogs the windshield, and eventually a wet passenger-side carpet with unexplained coolant loss. A common older-Jeep HVAC searc… Repairs typically run $400-$900. Severity: medium.

What is the 1997-2006 Jeep Wrangler Throttle Position Sensor (TPS) Failure — Erratic Idle, Stalling & Shift Problems?

The throttle-body-mounted TPS wears and produces an erratic voltage signal, causing high/hunting idle, stalling at stops, hesitation or bucking on acceleration, and — on automatics — erratic or harsh shifting. A very common, high-search TJ driveability complaint that often illumi… Repairs typically run $50-$220. Severity: medium.

What is the 2000-2006 Jeep Wrangler Radiator End Tank Cracking and Coolant Leaks?

The TJ/LJ Wrangler commonly develops coolant leaks from the plastic radiator end tanks, especially near the upper hose neck or crimp seam. Heat cycling and age make the plastic brittle, and owners often first notice a sweet smell, dried coolant residue, or overheating in traffic… Repairs typically run $250-$700. Severity: medium.

What is the 1994-2006 Jeep Wrangler 4.0L Two-Piece Rear Main Seal Oil Leak?

A leaking rear main seal is nearly universal on high-mileage 4.0 Wranglers — the two-piece crankshaft seal hardens and weeps oil at the back of the block, dripping onto the bellhousing and often collecting at the transmission. It is one of the most-searched 4.0 oil leaks and is f… Repairs typically run $200-$700. Severity: medium.

What is the 1997-2010 Jeep Wrangler Dana 30 Front Ball Joint Wear — Clunking, Wandering & Steering Vibration?

The solid-axle Dana 30 front end uses pressed-in upper and lower ball joints that wear out on high-mileage Wranglers, especially lifted rigs with larger tires. Worn ball joints introduce play in the steering knuckle, causing clunking over bumps, loose/wandering steering, uneven t… Repairs typically run $200-$700. Severity: medium.

What is the 2000-2006 Jeep Wrangler Exhaust Manifold Cracking on 4.0L Inline-Six?

A very common TJ Wrangler problem is cracking of the 4.0L exhaust manifold/header, especially around the collector and expansion joints. Repeated heat cycling and engine movement fatigue the factory manifold, leading to ticking noises on cold start, exhaust smell, and sometimes f… Repairs typically run $400-$1,200. Severity: medium.

What is the 2000-2006 Jeep Wrangler Blower Motor Resistor and HVAC Fan Speed Failure?

TJ Wranglers commonly lose one or more cabin fan speeds because the blower motor resistor overheats or the connector melts. Owners usually notice the fan only works on high speed, or stops working on lower settings first. The issue is well documented in owner forums and service p… Repairs typically run $40-$300. Severity: low.

What is the 1994-2006 Jeep Wrangler 4.0L Valve Cover Gasket Oil Leak?

One of the most common 4.0 oil leaks: the valve cover gasket hardens and seeps, typically worst at the rear of the head, leaving oil and grime down the back of the block and sometimes dripping onto the exhaust (burning-oil smell). Frequently mistaken for a more serious rear main… Repairs typically run $30-$300. Severity: low.

What is the 1994-2006 Jeep Wrangler NP231 Transfer Case Rear Output Shaft Seal / Slip-Yoke Leak?

The NP231 (Command-Trac) transfer case in YJ/TJ Wranglers uses a slip-yoke rear output. The rear output shaft seal is a chronic leak point — the exposed slip yoke picks up grit and rust that scores the seal, and a worn tail-housing bushing lets the yoke move and tear the seal. Re… Repairs typically run $20-$400. Severity: low.

Jeep · Known Issues

2003 Jeep Wrangler Problems: 17 Known Issues

2003 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated September 2026

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According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2003 Jeep Wrangler has 17 documented known issues, with 6 rated critical. The most serious are In-Tank Fuel Pump Module Failure — Whine, Hard Start & No-Start ($200-$550 repair), Clock Spring Failure Causing Airbag Light, Horn, and Cruise Control Loss ($250-$700 repair), Front Frame Rust and Control Arm Bracket Corrosion ($800-$5,000 repair), Body Tub, Floor Pan & Body-Mount Rust (Torque Box Corrosion) ($400-$3,500 repair), 4.0L Crankshaft Position Sensor Thermal Failure — Random Stalling & Hot No-Start ($60-$250 repair) and Dana 35 Rear Axle Shaft C-Clip Failure ("Grenade") ($300-$2,200 repair). Across all issues with published estimates, repair costs range from $20 to $5,000. DIY maintenance guides at au7o.io.

Frequently Asked Questions

What are the most common Jeep Wrangler problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2003 Jeep Wrangler has 17 documented issues. The most frequently reported are: In-Tank Fuel Pump Module Failure — Whine, Hard Start & No-Start, Clock Spring Failure Causing Airbag Light, Horn, and Cruise Control Loss, Front Frame Rust and Control Arm Bracket Corrosion. Of these, 6 are rated critical and should be addressed promptly.

Is the Jeep Wrangler reliable?

The 2003 Jeep Wrangler has 17 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 6 issues are rated critical: In-Tank Fuel Pump Module Failure — Whine, Hard Start & No-Start and Clock Spring Failure Causing Airbag Light, Horn, and Cruise Control Loss and Front Frame Rust and Control Arm Bracket Corrosion and Body Tub, Floor Pan & Body-Mount Rust (Torque Box Corrosion) and 4.0L Crankshaft Position Sensor Thermal Failure — Random Stalling & Hot No-Start and Dana 35 Rear Axle Shaft C-Clip Failure ("Grenade"). Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Jeep Wrangler problems?

Repair costs for known Jeep Wrangler issues range from $20 to $5,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, In-Tank Fuel Pump Module Failure — Whine, Hard Start & No-Start, typically costs $200-$550 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 1997-2006 Jeep Wrangler In-Tank Fuel Pump Module Failure — Whine, Hard Start & No-Start?

The in-tank fuel pump module (pump, sending unit, and level float) wears out on high-mileage TJ Wranglers, producing a loud whine from the tank, hard starting, stalling, and eventual crank-no-start as fuel pressure drops. A top-searched TJ fuel-system failure, sometimes accompani… Repairs typically run $200-$550. Severity: high.

All 17 Known Issues

Other Jeep Models

Frequently Asked Questions

What are the most common Jeep Wrangler problems?

Is the Jeep Wrangler reliable?

How much does it cost to fix common Jeep Wrangler problems?

What is the 1997-2006 Jeep Wrangler In-Tank Fuel Pump Module Failure — Whine, Hard Start & No-Start?

What is the 2000-2006 Jeep Wrangler Clock Spring Failure Causing Airbag Light, Horn, and Cruise Control Loss?

When Issues Typically Appear

2000-2006 Jeep Wrangler: Front Frame Rust and Control Arm Bracket Corrosion#

1994-2006 Jeep Wrangler: Body Tub, Floor Pan & Body-Mount Rust (Torque Box Corrosion)#

1997-2006 Jeep Wrangler: 4.0L Crankshaft Position Sensor Thermal Failure — Random Stalling & Hot No-Start#

2000-2006 Jeep Wrangler: Catalytic Converter Failure and Pre-Cat Efficiency Codes on 4.0L#

2000-2006 Jeep Wrangler: Ignition Coil Rail Failure Causing Misfire on 4.0L#

1994-2006 Jeep Wrangler: 4.0L Two-Piece Rear Main Seal Oil Leak#

2000-2006 Jeep Wrangler: Exhaust Manifold Cracking on 4.0L Inline-Six#

1994-2006 Jeep Wrangler: 4.0L Valve Cover Gasket Oil Leak#

1997-2006 Jeep Wrangler: In-Tank Fuel Pump Module Failure — Whine, Hard Start & No-Start#

1997-2006 Jeep Wrangler: Throttle Position Sensor (TPS) Failure — Erratic Idle, Stalling & Shift Problems#

1994-2006 Jeep Wrangler: Dana 35 Rear Axle Shaft C-Clip Failure ("Grenade")#

1994-2006 Jeep Wrangler: NP231 Transfer Case Rear Output Shaft Seal / Slip-Yoke Leak#

2000-2006 Jeep Wrangler: Clock Spring Failure Causing Airbag Light, Horn, and Cruise Control Loss#

1997-2006 Jeep Wrangler: Heater Core Leak — Coolant Smell & Fogged Windshield#

2000-2006 Jeep Wrangler: Radiator End Tank Cracking and Coolant Leaks#

1997-2010 Jeep Wrangler: Dana 30 Front Ball Joint Wear — Clunking, Wandering & Steering Vibration#

2000-2006 Jeep Wrangler: Blower Motor Resistor and HVAC Fan Speed Failure#