LUCAS MEMS 2J - Known Fitments
Vehicle makes, models and variants known or believed to be using this vehicle system, required diagnostic lead and degree of known compatibility.

Vehicle Make Vehicle Model Vehicle Variant Diagnostic Lead Compatibility Level
Rover Mini 1300 1300 MPI Black OBDII Lead Verified
Rover 200 K1800 VI (Inc Coupe) Black OBDII Lead Verified
Rover 400 1.8 Litre VVC Black OBDII Lead Verified
Rover 800 2.5 Litre V6 Black OBDII Lead Verified
MG MGF K1800Vi Black OBDII Lead Verified

LUCAS MEMS 2J - Physical Details
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LUCAS MEMS 2J - Pin Outs
Details of the pin usage for the ECU connector(s).

BLACK CONNECTOR  
1 Not used
2 Control valve (1 increase)
3 Not used
4 Fan (2) relay
5 - 7 Not used
8 MAP sensor
9 A/C sense
10 Oil temperature sensor
11 Not used
12 Throttle pot
13 Sensor ground
14 Inlet air temperature sensor
15 Coolant temperature sensor
16 Not used
17 Engine immobiliser
18 Throttle pot
19 Fan relay request
20 Oxygen sensor relay
21 ECU ground
22 Main relay control
23 Control valve (2 decrease)
24 Not used
25 Ignition coil 1
26 Ignition coil 2
27 Power feed
28 Fan 1 relay
29 A/C active
30 Fuel pump relay drive
31 - 32 Not used
33 Ignition sense
34 - 35 Not used
36 MAP sensor

RED CONNECTOR  
1 Cam sensor +
2 CAM sensor -
3 - 8 Not used
9 Tachometer
10 Stepper motor
11 Not used
12 Injector
13 Injector
14 Injector
15 Stepper motor
16 ECU ground
17 Purge valve
18 - 23 Not used
24 ECU ground
25 Crank sensor +
26 Crank sensor -
27 Oxygen sensor +
28 Oxygen sensor -
29 Not used
30 Speed sensor
31 Diagnostic line (K line)
32 Not used
33 Stepper motor
34 Stepper motor
35 Injector
36 Not used

SM072 - LUCAS MEMS 2J - Diagnostic Capabilities (Read Fault Codes)
This function reads the faults from the MEMS fault code memory. This memory not only stores codes associated with events which may have occurred in the past and have triggered the code being stored, requiring the memory to be cleared, but also has some internal fault statuses which use the fault memory dynamically, setting a code associated with a missing sensor input, but automatically clearing it whenever the sensor input is being detected again. This means that for some inputs which are only available when the engine is running, such as the crank sensor input, are shown as missing when the engine is stationary.

SM072 - LUCAS MEMS 2J - Diagnostic Capabilities (Clear Fault Codes)
This function checks the fault code memory for resident faults and clears the fault code memory if the fault has been rectified. Having deleted the faults the system then rechecks the fault memory to ensure that it is clear. Failure to clear the fault memory successfully is usually due to the system re-logging the fault the moment the fault memory is clear, meaning that the fault has not been rectified properly and as far as the system is concerned, still exists. The system may also carry out a re-check for successful clearing of the fault code memory but then the system may re-log the fault shortly after.

SM072 - LUCAS MEMS 2J - Diagnostic Capabilities (Settings)
Values, configuration settings, and other stored information which can be read from the ECU, edited and then rewritten back. Read settings can also be stored as a standard HTML page for reference. These pages can then later be re loaded and re written back to the ECU. Please note that some values may be read only due to the fact that they are supplied from the ECUs ROM or are internally calculated.

  • ECU configuration map ID: The code is shown exactly as it is stored with each of the 5 ID letters and 3 revision numbers being duplicated twice. With the duplicates stripped out, the resulting code should match the ECU configuration map ID code.
  • Vehicle type: This shows the vehicle type for this MEMS ECU.
  • ECU configuration map ID code: This code is made up from 5 letters followed by 3 numerical digits and is stored in the fuel tune data area. It uniquely identifies this specific fuel tune data map and the vehicle.
  • Fuel tune map ID code: The first five letters of the fuel tune ID code denote application usage as follows:
      knh7 Rover 800 KV6 AUTOMATIC
      kph7 Rover 800 KV6 MANUAL
      ksh8 Rover Coupe Vi
      kshb Rover 200 Vi
      ksh3 MGF
      adhm Mini

SM072 - LUCAS MEMS 2J - Diagnostic Capabilities (Inputs)
Realtime live display of the information the electronic control unit of the selected vehicle system is currently deriving from its input sensors.

  • Coolant Temperature (C): This displays the coolant temperature as measured by the ECU. The value should rise smoothly during the engine warm up from the ambient temperature to approximately 85C. A faulty temperature sensor may cause poor starting, fuel consumption, fast idle speed and cooling fans to run continuously.
  • Oil Temperature (C): This displays the oil temperature measured by the ECU. The value should rise smoothly during the engine warm up from the ambient temperature to approximately 85C. A faulty temperature sensor may cause fuelling and idle speed problems.
  • Inlet Air Temperature (C): This displays the temperature measured by the ECU using the inlet air temperature sensor. The inlet air temperature is used by the ECU to retard the ignition timing to avoid knock and trim the fuelling when hot. If the sensor is not operating correctly the engine performance may be impaired slightly.
  • Ambient Temperature (C): This displays the ambient temperature in the engine bay measured by the ECU using the ambient air temperature sensor. This is done to control an extra engine bay cooling fan on vehicles which require this. A faulty temperature sensor will effect the normal operation of the cooling fan.
  • Fuel Rail Temperature (C): This displays the temperature measured by the ECU using the fuel rail temperature sensor. This reading is used by the ECU to make correction to fuelling and as an aid to hot starting. A faulty sensor can alter the performance of the engine and hot starting.
  • Manifold Pressure (KPa): This displays the pressure measured by the external MEMS air pressure sensor. Normal reading with the engine not running is approximately 100 KPa and 30-40 KPa when the engine is idling. Very high values may indicate problems with the sensor or a blocked or disconnected vacuum pipe. Moderately raised values may indicate mechanical problems with the engine.
  • Throttle Angle (deg): This displays the position of the throttle disc obtained from the MEMS ECU using the throttle potentiometer. This value should change from a low value to a high value as the throttle pedal is depressed. Accepted values are between 0 and 369 deg.
  • Throttle Status: This displays the status of the throttle position as received from the throttle position sensor. If the switch shows open when the throttle is closed then the vehicle will not idle correctly and the closed throttle position may need to be reset.
  • Feedback (Oxygen Sensor Feedback Correction: Display of the current feedback fuelling correction. This is shown as a percentage of the mapped (open loop) value. This percentage is continuously updated by the MEMS ECU whenever the conditions for closed loop fuelling are present. Other times the feedback value will show 100% indicating that closed loop fuelling is not operational. High values of feedback (e.g.120%) indicate that feedback is at tempting to compensate for fuelling being too lean and low values (e.g.80%) for fuelling being too rich. Note: Misfire condition will be shown as high values as feedback will be fooled into compensating for a system running too lean. There are two values shown the first is for single sensor configurations or Bank 1 in dual bank configurations and the second is for Bank 2 and will show as 0 in single bank configurations.
  • Oxygen Sensor: These values show the voltage across the oxygen sensors as read by the MEMS ECU. Once the engine is fully warm, during most idle and driving condition this voltage will be alternating from above 2.025v to below 1.575v. The sensor detects the presence or absence of oxygen in the exhaust gas. When the exhaust gas has oxygen present the ECU will read a low voltage.
    There are two values shown, the first one displays the voltage of the single sensor in single sensor configurations or the sensor serving bank 1. The second voltage is the Bank 2 sensor and is only active in dual sensor configurations. This always reads zero in single sensor configurations.
  • Feedback States: This shows whether the fuelling is being controlled using feedback from the oxygen sensors. On a fully warm vehicle, the fuelling should be ACTIVE under most driving and idling conditions. There are two values shown, the first one displays the feedback state of the ECU in single sensor configurations or the feedback state of bank 1 on dual bank (2 sensor) configurations. The second displays the feedback control state of Bank 2 and is only active in dual bank (2 sensor) configurations. This always reads OPEN in single sensor configurations.
  • Required Cam Period: This display the cam period that the MEMS ECU is trying to achieve for a set of given driving conditions. If the required and measured cam period do not closely correspond this may indicate possible faults with the Vi mechanism.
  • Measured Cam Period: This displays the current cam period as measured by the MEMS ECU. If the required and measured cam period do not closely correspond this may indicate possible faults with the Vi mechanism.
  • Ignition Switch: This shows the state of the ignition switch as read by the MEMS ECU.
  • A/C Switch: This shows the state of the air condition request signal at the MEMS ECU. This signal depends on the state of the air condition switch, the blower fan control, the air con thermal switch and the trinary high/low pressure switch. The ECU will not show air con on unless all of these switches are on. The thermal switch will be off if the temperature of the air leaving the evaporator is less than about 3 C and the high/low pressure switch will be off if the pressure of the refrigerant is too high or too low.
  • Drive Switch: This reading is valid only for vehicles with automatic transmission. This shows the measured state of the Park/Neutral switch. This switch is used to improve the quality of engine idle speed control on automatic gearbox vehicles. A fault with this switch will cause the idle speed to dip or rise suddenly when the gear selection is changed between neutral and drive.
  • Fan Request: This shows the ECU fan request input. This input will be active if the air condition trinary medium pressure switch is closed requesting that the ECU fan control is set to maximum (fans on high speed).
  • Battery Voltage: This shows the voltage of the vehicle supply measured internally by the ECU. Large errors in this measurement will lead to possible poor starting and errors in idle CO.
  • Crankshaft Synchronisation: This shows the state of the crank. This should read SYNCRONIZED when the engine is running.
  • Camshaft Synchronization: This shows the state of the cam. This should read SYNCRONIZED when the engine is running.
  • Stepper Position (steps): This shows the position of the IACV stepper motor as calculated by the ECU. The ECU has no method of actually measuring this position but instead works it out by remembering how may steps it has moved the steppers since the last time the ignition was switched off. If a stepper motor fault exists this number will be incorrect. This value will normally be changing during idle conditions the ECU makes minor changes to the idle speed. A value of 0 during idle conditions indicates a fault condition or poor adjustment as does a very high value.
  • Engine Speed: This shows the rotational speed of the engine, calculated by the MEMS ECU using the crankshaft sensor. Faults in the crankshaft sensor or associated wiring may be indicated if this display reads 0 during engine cranking.

SM072 - LUCAS MEMS 2J - Diagnostic Capabilities (Outputs)
Choice of outputs that can be tested. The outputs will be pulsed for 10 seconds and it will error if the feature is not fitted.

SM072 - LUCAS MEMS 2J - Diagnostic Capabilities (Other)
Choice of functions that can be performed

  • Read security status: MEMS 2J ECU has improved capabilities in terms of allowing diagnostic checking of the status of the security input line.
  • Security learn mode: This function causes the MEMS 2J ECU to learn a new mobilisation code and would be required to mobilise the engine if either the Alarm or the MEMS 2J ECU have been changed. After using the function you will need to turn the ignition off and then on.
  • Coil Test: Make sure that you have the hand brake on and park or neutral selected as this test might momentarily start the engine. The test will display the charge time for each coil.
  • Reset adaptive values: This causes the MEMS 2J ECU to reset all adaptive values and re learn them.