System Specific Notes

Note regarding diagnostic trouble code (DTC) readout:
The left (N3/11) and right (N3/12) engine control module for the ME-SFI system is equipped with diagnostic trouble code (DTC) memory. All DTC's are readable via the right control module only. 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.

The DTC memory remains active 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.

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 > 80 °C.

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

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". DTC's can also be read using a generic scan tool via the OBD II connector located in the driver's footwell.

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

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 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 at idle speed is ± 1.0 milliseconds (injection duration) and at partial load the factor is 0.77 - 1.28. After repair work is performed, the engine control module will automatically adapt itself again.

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,
- Catalytic converter (TWC),
- Non-catalytic converter (non-TWC),
- Country version.

Note regarding drive authorization system (DAS) stage 2 and stage X:
Vehicles with ME-SFI are equipped with a drive authorization system (DAS) stage 2. The activation/deactivation of the drive authorization system takes place from the RCL control module (stage 2) or from the DAS control module (stage X) via CAN data bus to the engine control module (ME-SFI). After activating the drive authorization system, the engine control module renders the fuel injection system inoperative.

On vehicles till 05/96 a drive authorization system stage 2 (DAS 2A) is installed. This drive authorization system can only be activated/deactivated with the IR transmitter or the master key.

On vehicles as of 06/96 a drive authorization system stage X (DAS X) is installed. The activation or deactivation is accomplished with transponder technology via the ignition key. As soon as the ignition key is turned in the steering lock the DAS control module receives a signal and the fuel injection system is made operative via the CAN data bus.

The engine control module and the RCL or 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 and RCL or DAS control modules from one vehicle to another is not possible!

NOTE: If an exchange engine control module is installed for test purposes, only 40 start attempts can be performed before the engine and RCL or DAS control modules "marry" 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).

Notes regarding automatic recognition of the mechanical end stop and wide open position of the throttle valve from the actuators:
The end stops of the throttle valves are determined by the actuator and stored in the engine control module.
After replacing one or both control modules or actuators, the mechanical end stop and wide open position must be determined and recorded. After interrupting the voltage supply from 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 at rest,
- 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 the engine control module after interruption of voltage supply, circuit 30:
If a rough running engine is noticed after a voltage interruption, the following conditions must be met:
- Engine coolant temperature approx. > 80 °C,
- Drive vehicle on dynamometer in selector lever position 4 or on the road in selector lever position 3.
- Increase engine rpm to approx. > 3500 rpm and then coast until engine rpm is approx. < 1200 rpm.
- Repeat procedure at least 3 times.

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 proceed as follows:

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

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

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

Notes regarding activation of CHECK ENGINE MIL (only USA)
With combustion misses (e.g. ignition or fuel mixture) the CHECK ENGINE MIL is activated intermittently (blinking). Affected are the DTC's P0300 to P0308.
With all other malfunctions, the MIL is illuminated continuously.

Notes regarding CKP sensor (L5) adaption
After the replacement of the ME-SFI control module and for the uneven running engine test, the toothed wheel sensor (CKP sensor) adaption must be performed as follows:
- ECT approx. 70 °C
- Drive vehicle with transmission selector lever in 3rd gear
- Increase engine rpm to > 3500 rpm and then coast until engine rpm attains 1200 rpm.
After the replacement of the CKP sensor (L5), the starter ring gear or the replacement of the engine, the toothed wheel sensor (CKP sensor) adaption must be first reset using the HHT, then perform the driving cycle as indicated above.

Notes for 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 Mangement.

- 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)
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 317).

- Correction program
The following corrections can be made with the HHT: (refer to HHT "Correction program" menu item)
1. Correction of idle speed in selector lever position P/N.
2. Correction of idle speed with selector lever in drive position.
3. Make fault setting conditions for uneven running recognition less sensitive.