Description
The A6121534979 is a factory-fitted engine management ECU for the Mercedes-Benz W209 CLK-Class — the rear-wheel-drive coupé and cabriolet produced between 2002 and 2010. This module handles all key petrol engine management tasks including fuel injection control, ignition mapping, variable valve timing coordination and cold-start enrichment, ensuring smooth and confident power delivery across the CLK’s performance-oriented drive range.
The ECU sits at the centre of the W209’s sensor network, reading live data from the airflow meter, oxygen sensors, knock sensors and throttle actuator to refine combustion on every cycle. The CLK’s sport-tuned engine maps are embedded in this unit’s calibration, making the condition of this ECU directly relevant to throttle response sharpness and the quality of high-load performance.
Symptoms that often lead W209 owners to suspect the ECU include misfires at mid-range revs that are not resolved by replacing plugs or coil packs, erratic idle or stalling when the engine is warm, loss of power accompanied by a Check Engine light, and fault codes logged for sensors that have been tested and proven good independently.
This is a genuine used OEM unit recovered from a W209 CLK-Class and tested for core function prior to listing. Used engine management modules may require coding or adaptation to the receiving vehicle’s EIS and immobiliser by a Mercedes specialist or suitably equipped workshop. Verify the part number with your existing ECU before purchasing.
Returns accepted only for genuine faults — faulty on arrival, not as described, or wrong part supplied — requested within 14 days, with all 3 anti-tamper stickers intact. No returns for change of mind, incorrect installation, coding/programming, or buyer compatibility errors; checking compatibility (OEM number, firmware, vehicle) is the buyer’s responsibility. Full policy: https://giantparts.eu/refund-and-returns/
