Notes on ME-SFI diagnostic trouble code memory - AD07.61-P-2000-10B

Notes on diagnostic trouble code memory 

The ME-SFI control module (N3/10) has a diagnostic trouble code memory. The detection of faults and their storage is differentiated as follows:

• Fault constantly present
• Loose contact faults that have occurred while driving

The diagnostic trouble code memory is erased when the vehicle battery is disconnected.

Faults which no longer occur are erased automatically from the diagnostic trouble code memory after max. 40 warm-up phases  .

, not for Model 463: the CHECK ENGINE malfunction indicator lamp comes on if the fault has already been stored in the last driving cycle  "CHECK ENGINE" malfunction indicator lamp goes off if a fault is no longer detected for 3 driving cycles under the same operating conditions (as stored for fault identification).

A warm-up phase or one trip is as follows:

warm-up phase 

• Coolant temperature at start < 35 °C
• Heating of the coolant to > 70 °C

trip 

• Time after start > 20 minutes
• Engine temperature > -7 °C
• Engine speed > 500 rpm
• All causal chains are checked during previous trips

One driving  cycle for a test comprises

• engine start,
• respective test is performed,
• engine turned off.

The stored faults can only be read out using the HHT  with ignition "ON" or with "engine running".

The pulse display as well as the diagnosis via duty cycle display are no longer necessary.

, not for Model 463: in line with legal requirements, faults can also be read out at the diagnosis test connector conforming to SAE standard, ISO 9141-2, with a generic scan tool.

Notes on self-adaptation of the mixture formation 

For vehicles with TWC, the lambda control determines the injection time so precisely that the fuel/air ratio in all operating states is always approx. Lambda 1 (corresponds to 14.7 kg air to 1 kg fuel). If faults occur due to:

• air leak,
• wear or coking of the fuel injectors,
• wear to the engine,
• transition impedance in the mass air flow sensor,
• damaging diaphragm-type pressure regulating valve,
• damaging switchover valve (purging),

the ME-SFI 2.0 control module automatically performs a correction of the mixture formation.

The correction variables are continuously calculated and permanently stored. The self-adaptation is performed additively when idling and multiplicatively with partial load. Correction in the rich or lean direction when idling is ± 1.0 ms (injection time) and with partial load has a factor 0.68 -1.32. After repair operations, the ME-SFI 2.0 control module adapts automatically.

Notes on drive authorization system stage 3 (DAS) 

For vehicles with the gasoline injection and ignition system (ME-SFI 2.0) a drive authorization system stage 3 is installed. The drive authorization system is activated by the EIS control module via the CAN data bus to the ME-SFI control module.

After the drive authorization system has been activated, the ME-SFI control module puts the injection system out of operation. The drive authorization system stage 3 can only be activated or deactivated with the electronic key. After the electronic ignition key has been inserted, the EIS enables the engine control system via the CAN data bus. Opening and closing the vehicle with the mechanical key does not affect the drive authorization system. The ME-SFI control module and the EIS control module are permanently locked to one another by an identification code. This identification cannot be deleted (see HHT actual values "drive authorization system" menu item 3/7). A trial exchange of the ME-SFI control module or the EIS control module in another vehicle is therefore not possible  .

If, for checking purposes, a new ME-SFI control module is installed, only a maximum of 40 starting operations may be performed and then the control modules are permanently locked to one another. Before starting for the first time, a variant coding must be performed for the ME-SFI control module using the HHT. In addition, identification must be initiated and the vehicle identification number must be entered (see HHT actual values "drive authorization system" menu item 3/7).

Notes on automatic detection of the lower mechanical limit stop and the full opening of the throttle valves of the actuators 

The limit positions of the throttle valves are detected by the actuator and stored in the ME-SFI control module.

After replacing the ME-SFI control module or the actuator, the mechanical limit stop for the throttle valve and the full-load position must be detected and stored again.

To do this, delete the stored data using HHT and program new data. When connecting the new ME-SFI control module to terminal 30 (B+) for the first time, the control module automatically performs an adaptation of the actuator with the ignition "ON" (lower mechanical limit stop and full-load position of the throttle valve).

Conditions for programming operation: 

• selector lever in position P/N.
• vehicle at rest
• engine at rest.
• coolant temperature between 5 °C and 100 °C.
• accelerator not depressed.

If all the conditions are met, leave the ignition switched on for at least 60 seconds  , then switch off the ignition for at least 10 seconds  !

The programmed value is only stored in the memory after 10 starting cycles, provided the voltage is not interrupted. If, for example, the battery is disconnected after the 9th starting cycle, the programming operation must be repeated.

Notes on sensor adaptation for smooth operation test 

After replacing the ME-SFI control module, crankshaft sensor, starter ring gear or engine mount, a sensor adaptation must be performed as follows:

• coolant temperature > 70 °C
• drive vehicle on street.

Vehicles up to 01/98 

• 4th gear, increase engine speed to approx. 2500 rpm and then decelerate to < 1500 rpm
• 2nd gear, increase engine speed to approx. 6100 rpm and then decelerate to < 4100 rpm. Increase engine speed again to approx. 6100 rpm and then decelerate to < 3000 rpm.
• Using HHT, check whether sensor adaptation has been performed.

Vehicles as of 02/98 

• 3rd gear, increase engine speed to approx. 2100 rpm and keep this speed for approx. 30 s with approx. 50 % load
• Using HHT, check whether sensor adaptation has been performed.

Notes on output dynamometer/tachometer dynamometer 

ESP or ASR chassis control systems must not be put out of operation by disconnecting the control modules because the wheel speed signals transmitted via the CAN data bus are needed in the ME-SFI and ETC control modules.

To switch off the brake and engine control intervention in the ESP and ASR systems, the function must be canceled in the respective control module as follows:

A. Operations without hand-held-tester 

• Switch off ignition.
• Connect adapter to test connector (X11/4).
• Connect socket 1 to socket 6.
• Start engine (BAS/ESP or BAS/ASR malfunction indicator lamp must go on!)

B. Operations with hand-held-tester 

• Switch off ignition.
• Disconnect connector at ESP/ASR hydraulic unit in the wheel house

(BAS/ESP or BAS/ASR malfunction indicator lamp must go on!)

Once the operation is completed, reconnect the connector and delete diagnostic trouble code memory with hand-held-tester! 

Notes on variant coding 

ME-SFI 2.0 control modules have a variant coding. The coding can only be performed with the hand-held-tester (automatically and manually, see notes on HHT "variant coding").

For the coding, the following vehicle versions must be noted:

• vehicle model
• engine
• MT/AT transmission
• without TWC
• national version
• variable speed limiting
• without lambda control