SevereAffected: 2012-201970,000–120,000 miles

Renault Clio Mk4 0.9 TCe 90bhp — Alternator / Smart Charge System Failure

Modern vehicles use smart charging systems to reduce engine load, but the complex regulators on the alternators frequently fail.

Severity

Severe

DIY Difficulty

Moderate

Est. Cost

£250–£450

OBD Codes

P0620P0622

Component Diagram

Electrics

Typical layout and location for the Electrics assembly.

Reference Illustration

Symptoms

Red battery warning light on dashboard
'Charging System Fault' message
Systems shutting down (radio, power steering) as battery depletes
Car fails to start

Root Cause

The internal voltage regulator or diode pack on the alternator burns out due to heat and age. Occasionally, a slipping auxiliary belt causes the issue.

How To Fix

Test battery voltage with engine running (should be 13.8V - 14.7V).
If below 12.5V, replace the alternator.
Always replace the auxiliary drive belt at the same time.
Cost: £250-450

Estimated Repair Costs

Repair Option	Est. Cost (GBP)
DIY (parts only)	£100–£180
Independent Garage	£250–£450
Main Dealership	£400–£720

Other Faults on This Variant

Thermostat Housing Leak

Severe

2012-201940,000–80,000 miles£150–£200

The plastic thermostat housing on the 0.9 TCe warps and cracks, leading to a rapid loss of engine coolant and severe overheating risk.

Timing Chain Stretch and Rattle

Severe

2012-201950,000–90,000 miles£600–£800

The 0.9 TCe 3-cylinder engine suffers from premature timing chain stretch, causing an aggressive rattle and potentially fatal engine timing slip.

VVT Solenoid Oil Leak

Minor

2012-201950,000–100,000 miles£10–£80

The Variable Valve Timing (VVT) solenoid located on the top of the cylinder head leaks oil, which runs down the front of the engine.

Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.