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RennTech ECU+ Upgrade for the 2011-2018 CLS 550: grey RennTech HHT tuner showing the OBD2 plug end

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Compact black power module - RennTech ECU+ Upgrade for the 2011-2018 CLS 550

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Back of the RennTech HHT tuner with its USB port and status lights - RennTech ECU+ Upgrade for the 2011-2018 CLS 550

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RennTech ECU+ (Plus) Upgrade 2011-2018 Mercedes-Benz CLS 550 C218

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Regular price: $2,405.60
Regular price: ~~$2,480.00~~
Sale price: $2,405.60
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Subtotal: $2,405.60

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RennTech ECU+ (Plus) Upgrade 2011-2018 Mercedes-Benz CLS 550 C218

Subtotal: $2,405.60

Not sure it fits? Text us your VINSee all fitment

Vendor: RennTech

SKU: 54.218.CLS550BT.F

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Overview

The 2011-2018 CLS 550 responds well to software, and RennTech has been writing engine calibrations since electronic engine management arrived in the mid-1980s. This ECU+ Upgrade rewrites ignition timing, throttle mapping, fueling and boost control on the 4.7L M278 twin-turbo V8, so the extra power arrives across the whole rev range without giving up everyday drivability. RennTech rates the CLS 550 at up to 540 hp and 705 lb-ft with this upgrade, a gain of 105 hp and 262 lb-ft.

Watch it explained

Features

Loaded through the RennTech HHT hand-held tuner via the OBD2 port, no ECU removal
The HHT stores the tuned and the factory file, so you can switch back to stock any time
Revised ignition timing, throttle mapping, air-fuel ratios and boost control
Gains across the entire rev range, not just at peak
Developed on RennTech's own dyno and road tested
Keeps factory-like drivability and reliability for daily use
93 octane or better recommended for the full calibration

What is included

RennTech calibration for your car
Delivery as listed by RennTech for this model (HHT tuner or ECU flash)

Specs

Part number	54.218.CLS550BT.F
Engine	4.7L M278 twin-turbo V8
RennTech rated output	540 hp / 705 lb-ft
Gain (RennTech)	+105 hp / +262 lb-ft

Fitment notes

For the CLS 550 (C218), 2011-2018 as listed by RennTech. Please include your VIN with the order so RennTech can confirm the exact application. The full calibration needs 93 octane or better fuel. Check the fitment table before ordering, and contact us if your car differs.

Fitment

Make	Model	Chassis	Year	Engine
Mercedes-Benz	CLS 550	C218	2011-2018	4.7L M278 twin-turbo V8

Fitment

Year	Make	Model
2012–2018	Mercedes-Benz	CLS550

Not sure? Text us your VIN and we’ll confirm.

Shipping & returns

Shipping: Orders ship via UPS, FedEx or USPS, from our facility near Los Angeles or directly from the manufacturer. Rates for many items are weight-based and shown at checkout. If you need it by a certain date, text us before you order.

Returns: Unused items in brand-new condition and original packaging can be returned within 30 days of the invoice date, with a 25% restocking fee unless otherwise specified. In some cases we can offer a lower fee with the balance as store credit. Shipping charges aren't refundable in either direction unless approved by AutoTalent.

Not returnable: special-order or custom items, and anything that has been installed, modified or altered.

Cancellations: free if the item is out of stock or we miss the ETA you agreed to. Other cancellations carry a 5% processing fee to cover card fees we can't recover. Special-order items can't be cancelled.

Damaged in transit? Report it to the carrier and to us within 48 hours, keep all packaging, and don't send anything back without our written approval.

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