Motronic Control Unit Me 7.8
Motronic Control Unit ME 7.8
The familiar Motronic ME 7.8 control unit serves as the engine controller, with an increased computer capacity of 40 MHz and a memory capacity of 1 MB. These enhancements are required on the new models to ensure the enhanced OBD scopes and to facilitate the Sport Chrono function. The Motronic control unit is additionally designed to actuate the VarioCam Plus system (valve lift switchover) and the double-flow distribution pipe in the intake system.
DME 7.8_40_LSU, data records for programming USA vehicles:
DME control unit 7.8_40_LSU is installed for the USA. This controller is designed for operation with LSU broadband oxygen sensors upstream of the pre-catalytic converters. Data records LEV MT and LEV AT are available for programming purposes.
Enhancement Of OBD
The familiar On-Board Diagnostics system (OBD > USA) for emission monitoring is used on these vehicles. This system is designed to warn drivers via an appropriate signal in the instrument cluster, of any emission or engine-related faults. The scope of functions is tailored to meet all the different regulations world-wide (OBD II LEV 2 or EOBD EU 4).
The Motronic control unit can be diagnosed using the PIWIS Tester to:
- Check Engine light lights up - emission-related fault.
- Check Engine light flashes - a fault causing damage to the catalytic converter has occurred.
Similar to the Cayman S (987) and 911 Carrera (997), the Boxster S also features the enhanced version of the On-Board Diagnostics system worldwide. Any occurring faults are stored with additional information (such as environmental conditions, fault counter and extended fault memory) in the fault memory of the Motronic control module and can be read out with the PIWIS Tester.
The additional scopes required specifically for California (included for all USA vehicles) are:
- More extensive sensor diagnosis - The operating range and plausibility of emission-related sensor signals, such as ambient pressure, ambient temperature, intake air temperature, engine oil temperature, fuel level and vehicle speed must be verified.
- Increased number of fault paths - Each fault type of a signal fault must be stored in a separate fault path.
- Enhanced field monitoring of the vehicle fleet - The function and fault management systems of the diagnostics system on standard production vehicles must be tested and documented every year.
Adaptation Of The Motronic Control Unit
The Motronic control units have been adapted to the engine-specific requirements of the following components and systems:
- ME 7.8_40_LSU: For USA vehicles, stereo lambda control with LSU broadband oxygen sensors upstream of catalytic converter, LSF step oxygen sensors downstream of catalytic converter
- VarioCam Plus (camshaft adjustment and valve lift switchover)
- Sequential fuel injection with EV-14 injection valves
- Electronic throttle
- Cylinder-specific knock control
- Static high-voltage system with individual ignition coils
- Load measurement using hot film mass air flow sensor HFM 5
- Two-stage resonance intake system
- Switchable double-flow intake air distribution pipe
- Oxygen sensor heating
- 2 parallel three-way catalytic converters, each with pre- and main converter
- Secondary air control
- Fuel tank leakage check using excess pressure
- Force coordination for Tiptronic and PSM
- On-Board Diagnostics system for monitoring emission control system (OBD II and EOBD)
- Infinite activation of the electronic radiator fans
- Engine compartment scavenging blower
- Air conditioning compressor control
- Cruise control function (via electronic throttle)
- Sport Chrono Package Plus (optional)
Input Signals Of The Motronic Control Unit
- Power supply terminal 15, terminal 30, terminal 87 and ground
- Engine speed sender
- Hall sender - inlet camshaft, bank 1 and bank 2
- Electronic accelerator pedal unit with pedal sensor 1 and 2
- Throttle potentiometers 1 and 2 (in the electronic throttle)
- Hot film mass air flow sensor HFM 5 (load signal and intake air temperature)
- Coolant temperature sensor (NTC)
- Knock sensor, bank 1 and bank 2
- LSU broadband oxygen sensors up line of catalytic converter, bank 1 and bank 2
- LSF oxygen sensors downstream of catalytic converter, bank 1 and bank 2 (worldwide)
- Oil temperature and oil level
- Oil pressure sensor
- Engine compartment temperature sensor (NTC)
- Tank leakage diagnostics module DM-TL
- CAN information
- Brake light switch
- Clutch pedal switch
- Fuel level
- Vehicle speed
- Environment class
- Immobilizer
- Sport Chrono button (option)
Drive Links Of The Motronic Control Unit
- Starter controller
- Fuel pump
- Injection valves for cylinders 1 to 6
- Individual ignition coils for cylinders 1 to 6
- Throttle position adjuster (electronic throttle)
- Cruise control (Speed Adjustment System SAS)
- Oxygen sensor heating
- Valve for valve lift switchover, bank 1 and bank 2
- Valve for inlet camshaft adjuster, bank 1 and bank 2
- Switching valve for tuning flap
- Switching valve for double-flow intake air distribution pipe
- Tank vent valve
- Tank leakage diagnostics module DM-TL
- Secondary air pump
- Cooling water fan right and left (via auxiliary control module)
- Engine compartment scavenging blower
- Cooling water shutoff valve (Tiptronic only)
- Air conditioning compressor relay
- "Check engine" lamp
Intervention Of The Motronic Unit In The Sport Chrono Functions
Sport Chrono Package Plus, which is familiar from the Cayman S (987) and the 911 Carrera (997), is also optionally available for the Boxster S. This option markedly increases driving pleasure, performance and vehicle dynamics. Sport mode can be activated via a button in the center console.
Motronic modifies the following functions when the Sport Chrono button is active:
- More dynamic accelerator pedal characteristic.
- Hard engine speed limiter.
- More sporty load cycle behavior.
NOTE: A complete description of the functions of the Sport Chrono Package Plus is to be found in the Service Information Technik for the Boxster (987) and 911 Carrera (997).