System Specific Notes

Note regarding diagnostic trouble code (DTC) readout:
The engine control module (N3/10) for the ME-SFI system is equipped with diagnostic trouble code (DTC) memory. Malfunctions are recognized and stored as DTC's and are distinguished as follows:
- Malfunctions which are constantly present,
- Intermittent contact malfunctions which have occurred during a trip and have been stored.

The DTC memory is erased when the vehicle's battery is disconnected.

Malfunctions which are no longer present, are automatically erased as follows:
- After three trips the "CHECK ENGINE" MIL goes out.
- After an additional 40 warm-up periods the DTC is automatically erased.
- "CHECK ENGINE" MIL is illuminated if the fault was stored on the previous driving-cycle.

A warm-up period or trip is defined as follows:

Warm-up period
- Engine coolant temperature at start < 35 °C,
- Engine coolant temperature increases to > 70 °C.

Trip
- Engine running for > 20 minutes,
- Engine oil temperature > - 7 °C,
- Engine speed > 500 rpm,
- All emission related logic chain functions already there were checked during previous trips.

Driving-cycle (for a test) consists of:
- Engine start
- Completion of test,
- Shutting engine: OFF

The stored DTC's can be read at the data link connector (X11/4) using the HHT only, with the ignition switched "ON" or with the "engine running".

Readout via an on-off ratio readout or impulse counter scan tool has been eliminated.

As required by law, the DTC's can be read out using the Generic Scan Tool, by connecting scan tool to the OBD II diagnostic connector.

Note regarding mixture preparation self-adaptation:
The Lambda control system determines the fuel injection duration so precisely that the fuel/air ratio is kept constant at Lambda level 1 (equals 14.7 kg air to 1 kg fuel) under all operating conditions.
Should malfunctions occur in the form of:
- Intake air leaks,
- Injector wear or carbon build-up,
- Engine wear,
- Transition resistance in MAF sensor,
- Defective diaphragm pressure regulator,
- Defective purge control valve, the engine control module (ME-SFI, 2.0) automatically performs a mixture adjustment.
The degree of correction is constantly calculated and permanently stored. The self-adaptation is performed additive at idle and multiplicative under partial load. The correction towards rich or lean is ±1 .0 milliseconds (injection duration) at idle and the factor 0.68 - 1.32 at partial load. After repair work is performed, the engine control module will automatically adapt itself again.

Note regarding drive authorization system (DAS 3):
Model Year 1998, models 202, 208 and 210
Vehicles with ME-SFI (ME 2.0) are equipped with DAS 3. DAS is activated from the DAS control module (N54/1) via the CAN data bus to the engine control module.
Upon activation of the DAS, the engine control module renders the fuel injection system inoperative. The activation or deactivation is accomplished only with the electronic ignition key. As soon as the electronic ignition key is inserted in the steering lock, the DAS control module receives a signal and activates the engine control via the CAN data bus.
The locking and unlocking of the vehicle, using the mechanical key has no effect on the DAS system.
The engine control module and the DAS control module are "married" to one another through identification codes. The identification codes can not be erased (see HHT nominal values "DAS", menu selection 3/7.)
Therefore, swapping the engine or RCL control module from one vehicle to another is not possible!

NOTE: If an exchange engine control module is installed for test purposes, up to 40 start attempts can be performed before the engine and DAS control modules "marry" to one another. Prior to performing the first start, the engine control module must be version coded using the HHT. Additionally, the code number and VIN must be entered (see HHT nominal values "DAS", menu selection 3/7.)

Note regarding version coding:
The engine control module is equipped with a version coding feature. The coding must be performed with the Hand-Held Tester (automatically or manually, see Notes for HHT "Version coding" below) upon installation of a new control module.
The following vehicle version data must be determined for coding:
- Vehicle model,
- Engine
- Non-catalytic converter (non-TWC),
- Country version,
- 30 km/h limitation

Notes regarding automatic recognition of the mechanical end stop and wide open position of the throttle valve from the actuator:
The end stops of the throttle valve is determined by the actuator and stored in the engine control module.
After replacing the control module or actuator, the mechanical end stop and wide open position must again be determined and recorded. Thereby allowing learned data to be erased with the HHT and new data to be learned. When the new engine control module is connected for the first time to circuit 30 (B +), the engine control module performs a self-adaptation of the actuator with the ignition "ON" (lower mechanical end stop).

Requirements for learning process:
- Selector lever in position P/N,
- Vehicle standing still,
- Engine off,
- Engine coolant temperature between 5 °C and 100 °C,
- Accelerator pedal not applied.

When all requirements are met, turn ignition ON for at least 60 seconds, then turn ignition OFF for at least 10 seconds.
The learned value is stored in memory, only after the first 10 start cycles, provided the voltage supply has not been interrupted. Should the battery be disconnected after the 9th start cycle, the re-learning process must be performed again.

Notes regarding VSS sensor adaption for rough running engine test:
After the replacement of the ME-SFI control module, CKP sensor (L5), starter ring gear or motor mount, a sensor adaption must be performed:
- Engine coolant temperature approx. > 70 ° C,
- Drive vehicle on road.

Vehicles up to 01/98:
- With selector lever in position 4: Increase engine rpm to approx. 2,500 rpm and then coast until engine rpm is approx. < 1,500 rpm.
- With selector lever in position 2: Increase engine rpm to approx. 6,100 rpm and then coast until engine rpm is approx. < 4,100 rpm. Again increase engine rpm to approx. 6,100 rpm and then coast until engine rpm is approx. < 3,000 rpm.
- Using the HHT, determine if VSS sensor adaption has taken place.

Vehicles as of 02/98:
- With selector lever in position 3: Increase engine rpm to approx. 2,100 rpm and then hold a 50% engine load for approx. 30 seconds.
- Using the HHT, determine if VSS sensor adaption has taken place.

Notes regarding performance/speedometer test:
Disconnecting the ESP/ASR/ETS/ABS control modules is not allowed. The engine control module and transmission control module rely on these modules to supply the VSS data via the CAN bus.

To disable the brake and engine regulation function of the ESP/ASR/ETS/ABS control modules:

A. Working without HHT
- Ignition: OFF.
- Connect HHT adapter to data link connector (X11/4).
- Bridge sockets 1 and 6.
- Engine: Start (BAS/ESP or BAS/ASR MIL must illuminate!).

B. Working with HHT
- Ignition: OFF.
- Disconnect front axle VSS sensor connector (BAS/ESP or BAS/ASR MIL must illuminate!).

When work is completed, reconnect VSS sensor connector and erase DTC's with HHT!

- Fault search with HHT
Diagnostic trouble code (DTC) memory: Select "Current DTC's". If the actual condition changes, e.g. when wiggling a connector, the change is reported optically and acoustically so that troubleshooting can be performed directly with the HHT.

- Loose connections
Loose connections are stored if they occur several times in a certain time period. Therefore, they can appear only as "Stored DTC's" and never as "Current DTC's".

- Nominal values
All nominal values relative to the actual values shown on the HHT are listed in Powertrain Management. Testing and Inspection

- Actual value for engine speed
For engine speed, the HHT display indicates the closed throttle speed (CTP) nominal value calculated by the control module on the left, and the rpm actual value on the right. Both values should differ from each other only slightly. Permissible tolerances are not yet determined.

- Version coding with HHT
a) Before replacement of the engine control module, the existing code number must be read and stored with the HHT (menu selection 5 "Version coding"). After installation of the new control module, the previously read code number must be entered.

NOTE: If returning a new control module to a PDC, the code number must be erased.

b) If the code number can not be read, the vehicle equipment/version must be determined, the corresponding code number obtained from parts data and manually entered with the HHT.

- Drive authorization system (DAS) X
Upon replacement the engine control module must be version coded using the HHT. Additionally, the code number and VIN must be entered (see HHT nominal values "DAS", menu selection 3/7.)