2003 Mercedes-Benz C240

2003 Mercedes-Benz C240

Overview

The 2003 Mercedes-Benz C240, part of the W203 generation, offered a blend of luxury and performance, though it wasn’t without its potential reliability concerns. This model year saw the introduction of various engine and transmission configurations, each with its own set of documented issues. While many owners report a generally positive experience, specific components, particularly within the electrical and engine systems, have shown a propensity for problems. Understanding these potential weaknesses can help prospective buyers and current owners budget for and address common repairs, ensuring the longevity of this executive sedan. The focus here is on recurring technical faults rather than routine maintenance.

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Engine

2.6L V6 (M112 E26)

Intake Manifold Gasket Leak

• Symptoms: Coolant leaks, sweet smell of coolant, engine misfires, overheating.
• Solution: Replacement of intake manifold gaskets.
• Cost: $300 - $600

Oil Cooler Seals

• Symptoms: Oil in coolant, coolant in oil, potential for engine damage if not addressed.
• Solution: Replacement of oil cooler seals.
• Cost: $400 - $700

Transmission

5G-Tronic Automatic (722.6)

Transmission Control Module (TCM) Failure

• Symptoms: Harsh shifting, slipping gears, ‘limp mode’ engagement, check engine light.
• Solution: Replacement or repair of the TCM.
• Cost: $800 - $1500

Conductor Plate Issues

• Symptoms: Erratic shifting, failure to engage gears, transmission warning light.
• Solution: Replacement of the conductor plate and associated sensors.
• Cost: $500 - $900

Suspension

Standard Chassis

No Major Issues

• Symptoms: No widespread issues reported.
• Solution: No widespread issues reported.
• Cost: No widespread issues reported.

Electrical

General Electrical System

SAM (Signal Acquisition Module) Failure

• Symptoms: Various electrical gremlins, including non-functional lights, wipers, power windows, and dashboard warning lights.
• Solution: Repair or replacement of the SAM module.
• Cost: $600 - $1200

Window Regulator Failure

• Symptoms: Power windows not operating, window getting stuck.
• Solution: Replacement of the window regulator mechanism.
• Cost: $250 - $450

Instrument Cluster Issues

• Symptoms: Pixelated displays, non-functional gauges, intermittent power loss to the cluster.
• Solution: Repair or replacement of the instrument cluster.
• Cost: $500 - $1000

Exterior

Body and Trim

No Major Issues

• Symptoms: No widespread issues reported.
• Solution: No widespread issues reported.
• Cost: No widespread issues reported.

Interior

Cabin Components

No Major Issues

• Symptoms: No widespread issues reported.
• Solution: No widespread issues reported.
• Cost: No widespread issues reported.

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Summary Verdict

The 2003 Mercedes-Benz C240 presents a mixed reliability profile. While the engine and transmission are generally robust, specific components like the intake manifold gaskets and the 5G-Tronic automatic transmission’s conductor plate and TCM can be sources of costly repairs. The electrical system is a notable area of concern, with SAM module failures and window regulator issues being relatively common. Owners should be prepared for potential electrical gremlins and transmission-related expenses. Suspension, exterior, and interior components tend to be more reliable, with no widespread critical failures reported. Regular maintenance and prompt attention to early signs of trouble are crucial for maintaining this vehicle.