Lotus 2004 Eleven Service Notes page 192

Lotus Service Notes
EMP.5 - 2006 MODEL YEAR ELECTRONIC THROTTLE CONTROL (ETC)
For '06 model year, the 2ZZ-GE engine is equipped with an electronic 'drive by wire' throttle in order to
meet Low Emissions Vehicle 2 emissions standards as dictated by California Air Resources Board. This is
achieved by allowing fuel pre-scheduling and consistency of load demand.
The mechanical throttle control cable is replaced by a pedal actuated potentiometer unit which feeds
pedal movement and position information to the engine management ECU. The ECU compares this demand
information with existing engine throttle position data, and outputs a suitable command signal to the DC step-
per motor which operates the throttle valve. For optimum safety, two output curves are produced by the pedal
unit and are fed into two processors contained within the ECU. Similarly, two streams of engine throttle valve
positional information are fed back into these processors, which are then compared by the ECU software. Any
discrepancies are analysed and appropriate safety oriented commands outputed to the throttle valve which may
be limited to a maximum 15% opening, or to a 7% mechanically sprung setting for 'limp home', or in extreme
cases, the injectors may be shut off.
Note that no IAC valve is required, as the idle air control function is incorporated into the electronic throt-
tle system.
ECU Communication
2006 model year cars with ETC have the VIN included in the ECU memory, without which the MIL will
be illuminated, and a fault code stored. The Lotus Scan tool requires an updated operating programme which
includes VIN download facility and is available on CD under part number T000T1466/2. This programme must
be downloaded on to a PC before being transferred to the Scan tool. The ECU progamme is also specific to
ETC, with an i.d. of A120E0030H (non USA) or A121E0010H (USA) .
Section EMP
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