Proton GEN-2
Launched in the United Kingdom in September 2004, the Proton GEN-2 marked a pivotal evolution for the Malaysian marque as its first clean-sheet family hatchback engineered around an in-house platform rather than recycled Mitsubishi architecture. Styled by the Lotus Design Studio and riding on a development of the well-received Impian platform, the GEN-2 boasted an assertive wide-track stance, distinctive coupe-like roofline, and surprising chassis poise tuned by Lotus Dynamics in Hethel. Power came from Proton's bespoke CamPro 1.3-litre and 1.6-litre 16-valve petrol engines, supplemented in 2008 by a four-door Persona saloon variant and an innovative dual-fuel ecoLogic LPG model that offered halved running costs with zero purchase price penalty. While UK motoring reviewers praised its crisp steering feedback and suppression of body roll, sales suffered from persistent British badge resistance, a spartan cabin dominated by hard brittle plastics, and a pronounced low-rpm torque flat spot on early non-IAFM CamPro units. In the modern sub-£1,000 used car market, surviving GEN-2s represent rare, highly affordable runabouts with engaging handling, provided buyers inspect thoroughly for suspension fatigue, sticky throttle bodies, and binding rear brakes.
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Common Faults & Reliability
These are the most common documented problems for the Proton GEN-2, sorted by their typical impact and frequency.
CamPro S4PH Electronic Throttle Body Carbon Fouling and Idle Speed Hunting
medium severityThe 1.6-litre CamPro S4PH engine utilizes an electronic throttle body assembly that is prone to oil mist and carbon contamination from the positive crankcase ventilation (PCV) system. Over time, gummy carbon deposits accumulate around the throttle butterfly plate and idle bypass bore. This disrupts the airflow calculations of the engine control unit (ECU), causing erratic idle hunting between 600 rpm and 1,300 rpm, delayed throttle response when pulling away, and sudden engine stalling when dipping the clutch at roundabouts or traffic lights. Cleaning the throttle assembly and performing an ECU idle relearn procedure is required to restore smooth operation.
Manual Gear Linkage Bush Perishing and Notchy Selection
low severityThe five-speed manual transmission linkages on the Proton GEN-2 rely on rubber and nylon pivot bushings beneath the cabin centre console and along the underbody selector rods. Due to heat from the exhaust tunnel and road grime ingress, these bushings degrade, perish, and develop excessive slop. The gear selector lever loses its positive spring-loaded gate definition, resulting in an imprecise, vague shift action, difficulty selecting first gear or reverse from neutral, and occasional gear crunching into second. Replacing the worn bushings with uprated polyurethane or new factory nylon bushes restores shift precision.
Rear Brake Caliper Slider Pin Seizure and Handbrake Inefficiency
medium severityThe Proton GEN-2 is equipped with rear solid disc brakes that incorporate an internal mechanical handbrake actuator lever on each caliper. Exposed to corrosive UK road salt and road wash, the rubber slider pin dust gaiters split and allow moisture into the guide bores. This causes the steel pins and internal handbrake return springs to corrode and seize. As a result, the rear brake pads drag persistently against the rotor, generating excessive brake dust, overheating the rear hubs, and leading to MOT failures for inadequate parking brake efficiency or brake effort imbalance exceeding 30 percent.
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