Lotus Elise / Lotus Exige. Manual - part 42

Page 42

 

 

Lotus Service Notes   

 

 

  Section EMP

Camshaft Lift Control (VVL)        P2646

                          P2647

                          P2648

                          P2649

P2646  A Rocker Arm Actuator System Performance or Stuck Off

P2647  A Rocker Arm Actuator System Stuck On

P2648  A Rocker Arm Actuator Control Circuit Low

P2649  A Rocker Arm Actuator Control Circuit High

Description

Intake and exhaust camshaft lift can be changed by means of the Variable Valve Lift (VVL) system, which varies 

the amount of maximum lift of the intake and exhaust valves.  The mechanism uses dual element rocker arms to 

provide cam changeover, with both the intake and exhaust camshafts having high and low speed cam profiles.  

The system is ECU controlled, using an oil control solenoid which, when activated, uses hydraulic pressure to 

push a rocker arm locking pin into engagement to activate the high-speed cam profile.  A signal from the VVL 

oil pressure switch provides feedback to the ECU that VVL activation has taken place.  VVL activation* to the 

high lift camshaft profile occurs at 6200rpm when engine speed is increasing, and returns to the low lift camshaft 

profile at 6000rpm when the engine speed is decreasing.

*Coolant temperature must be >60°C (140°F).

Component connections

Connector    Description            ECU Pin      ECU Connector

1          Battery Voltage         -          -

2          VVL Oil Control Valve     12 (H3)      52 Way (Right)

                                                   

'06 M.Y. in brackets

-          VVL Oil Pressure Switch    21 (B2)      52 Way (Right)

Monitor: Continuous

Enable Criteria: Engine running

Disable Criteria: None

Potential failure modes:

•  VVL valve stuck open / closed

•  VVL valve open circuit

•  VVL valve short to ground

•  Rocker arm failure

•  Rocker shaft location pin failure

•  ECU output circuit failure

Notes:

The MIL will be illuminated if the fault is present for 2 consecutive trips.

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Lotus Service Notes   

 

 

  Section EMP

Page 43

EMP.2 - ‘LOTUS SCAN’ DIAGNOSTIC TOOL

In order to provide for communication with the engine management system electronic control module, a 

hand held electronic scanner ‘Lotus Scan’ (part number T000T1418F), may be plugged into a special 16 terminal 

harness connector socket, known as a Data Link Connector (DLC), located at the front of the passenger footwell.  

Note that this tool may also be used on previous Elise models (excluding Exige, 340R and 160 models).

Amongst the operations available using the ‘Lotus Scan’ tool are:

- 

Reading of Trouble Codes

- 

Clearing of Trouble Codes

- 

Reading live data

- 

Test operation of individual solenoids

- 

Running engine history report

- 

Reprogramming ECU

 

Operating instructions are provided with the tool.

Important Note 

The power supply transformer is used for overnight charging of the printer, and also for powering  the Scan 

tool during software downloading from a PC (personal computer).  For the software download operation, the 

Scan tool requires a power supply from the mains via the transformer and an inverter.  Two types of inverter 

have been used; early kits used an adaptor lead to plug into the bottom end of the Scanner tool.  Later kits use 

an adaptor plug fitting into the top end of the scanner.

When charging the printer, it is most important that the inverter is NOT used, or damage to the transformer 

may be caused.  Incorrect connection is possible only with the early type adaptor lead, with which extra care 

should be exercised.

1.  Reading data from vehicle

    Data Link Connector (DLC)                Scan tool

    (front of passenger footwell)     

                                                  Printer

                                  

                                                                 

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Page 44

 

 

Lotus Service Notes   

 

 

  Section EMP

2.  Downloading software from P.C.

   

  With early type adaptor lead

    Connect to COM                                              Power 

    port on PC                                                  supply

                                                            transformer

    Adaptor lead used 

    to connect to 

    transformer                                                         

em192c

With later type adaptor

    Connect to COM                     

    port on PC                       

   

                         

                                                            Power

                                                            supply

                                                            transformer

                                      Power supply adaptor                 

em192f

                                          T000T1436F

3.  Charging printer

                          Power supply

                          transformer

    Do NOT use adaptor

    lead for this application

                                                    Printer

                                                                     

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Lotus Service Notes   

 

 

  Section EMP

Page 45

EMP.3 - ENGINE MANAGEMENT COMPONENT LOCATION

Key to engine management component location drawing

1.  Electronic Control Unit (ECU).

2.  Multi-function relay unit.

3.  Oil control valve for variable valve lift.

4.  Camshaft position sensor.

5.  Fuel injector.

6.  Knock sensor.

7.  Oil control valve for variable valve timing.

8.  Crankshaft position sensor.

9.  Plug top coil.

10.  Coolant temperature sensor.

11.  Pre-catalyst oxygen sensor.

12.  Post-catalyst oxygen sensor.

13.  Oil pressure switch.

14.  Throttle position sensor.

15.  Vacuum solenoid for intake flap valve.

16.  Mass airflow sensor.

17.   Idle Air Control (IAC) valve - prior '06 M.Y.

For component replacement procedures, refer to manual B120T0327J.  

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