Engine Control Unit

Car	ECU	Protocol/Bus	Scanner	Notes
Elise S1 (120bhp)	MEMS 1.9	proprietary	LotusScan (Connector SAE J1962) or Rover Test-Book Omitec	12, 10 or 5 pin?
Elise S1 111S	MEMS 2J	proprietary	LotusScan (Connector SAE J1962) or Rover Test-Book Omitec
Elise S1 Sports 160	GEMS (SVA, 50 cars) or EFi Euro1(EWVTA)
Elise S1 Sports 190	MEMS 1.9 (or Lotus K4 update kit)	proprietary	LotusScan (Connector SAE J1962) or Rover Test-Book Omitec
Exige S1 340R	Lotus "918" ECU (As used in Esprit V8)	K-Line (9141)	LotusScan2 (Connector SAE J1962)	Manufactured by EFi Technology Srl.
Elise S2 K Series	K4	K-Line (9141)	LotusScan2 (Connector SAE J1962)	Manufactured by EFi Technology Srl.
Elise S2 111R Exige S2	T4	K-Line (9141)	LotusScan3 (Connector SAE J1962)	Manufactured by EFi Technology Srl.
Elise S2 Exige S2 with electronic throttle	T4e	K-Line (9141) MY08 onward CAN	LotusScan3 (Connector SAE J1962)	Manufactured by EFi Technology Srl.
Non Standard ECUs
N/A	MEMS 3	KWP2000
N/A	Emerald

S1 = For a s1 it's inside the boot on the left as you look at the car, near the bottom but on the back wall, peel back the carpet and you'll see it. S2 = On a S2 its under the dash on the passenger side above the foot rest.

K Series Elises

EFi Technology EURO1 ECU

EFi Technology Srl ( http://www.efitechnology.it ) "Euro1" ECU: Fitted to EWVTA S1 Sport160 cars.

Lotus K4 ECU

Lotus K4 Engine Control Unit: fitted to S2 Elise with K-series(i.e. 122ps, 135ps, 158ps VVC, Sport190)

Toyota Elises

Lotus T4 ECU

Lotus T4 Engine Control Unit: fitted to all manual throttle controlled Toyota 2ZZ-GE engined cars.

Lotus T4e ECU

Lotus T4e Engine Control Unit: fitted to electronically throttle controlled Toyota 1ZZ-FE, 2ZZ-GE and 2ZZ-GZE engined cars.

Aftermarket ECUs

Emerald M3DK

The Emerald M3DK is a plug compatible replacement ECU for the Rover MEMS unit used on the K series, it utilises the existing engine sensors and works with distributor based systems and distributorless 'wasted spark' systems. It is compatible with the immobiliser as fitted to Elises and Caterhams. It is fully programmable and comes complete with software, manual, comms cable and example maps. It has user tailorable soft and hard cut rev-limits and a user programmable shift light.

ECU mapping

If you make substantial changes to your car setup or simply want to ensure that the ECU is correctly configured to control the fuel system, then you could consider a "mapping" session on a rolling road.

ECUs generally work by comparing the engine speed in rpm to the position of the throttle. The ECU then compares these values on a "map" to find the correct amount of fuel to add. This ensures that an engine is not running too rich or too lean, both of which can be undesirable with the latter leading to detonation.

The mapping process will involve your car being run on a rolling road for a period of time, with an operator changing the map on the fly. The rolling road will then allow the operator to add the optimum values to the map.

Name & Website	Address & Google map reference
JKM Performance	Bolde Close, Copnor, Portsmouth, Hampshire, PO3 5RD

See Also

• http://en.wikipedia.org/wiki/Engine_Control_Unit
• http://en.wikipedia.org/wiki/OBD-II_PIDs

Forum links

• http://forums.seloc.org/viewthread.php?tid=143423
• http://forums.seloc.org/viewthread.php?tid=71330

External links

• http://www.sae.org/technical/standards/J1962_200204