ME-SFI diagnosis fault memory function - GF07.61-P-2004F

ENGINE 104.941 /943 /944 /991 /994as of 1.8.96

ENGINE 104.995

with CODE (494a) USA version

with CODE (807) Model year 1997

with CODE (808) Model year 1998

with CODE (498) as of Model year 97 Japanese version

ENGINE 111.921 /942 as of 1.9.98,

111.943,

111.944 as of 1.8.96,

111.946 as of 1.6.98,

111.947/973,

111.975 as of 1.8.96

ENGINE 111.945

in MODEL 208.335/435 as of 1.6.98,

202.020/080 as of 1.9.98

ENGINE 111.974

with CODE (494a) USA version

with CODE (807) Model year 1997

with CODE (808) Model year 1998

ENGINE 112.910 /911 /912 /913 /914 /916 /917 /920 /921 /922 /923 /940 /941 /942 /943 /944 /946 /947 /949 /953 /954 /955 /970 /972 /973 /975

ENGINE 113.940 /941 /942 /943 /948 /960 /961 /963 /965 /966 /967 /968 /969

ENGINE 119.980/981/982/985

ENGINE 120.982/983

ENGINE 137.970

Fig 1: Identifying ME-SFI Diagnosis Fault Memory Function (1 Of 2)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 2: Identifying ME-SFI Diagnosis Fault Memory Function (2 Of 2)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Shown on model 210

Fig 3: Identifying Data Link Connector - Shown On Model 210

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The ME-SFI control unit checks its inputs and outputs for plausibility and recognizes possible faults. The identification of faults and their storing is differentiated as follows:

Faults permanently existing

Loose contact faults.

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

Reading out fault memory

The stored faults can only be read out and erased with the HHT or the STAR DIAGNOSIS when ignition is "ON" or when "engine running" at the diagnostic data link connector

In line with legal requirements, faults can also be read at the data link connector conforming to SAE standard, ISO 9141-2, with a generic scan tool.

Engine 120

The ME-SFI control units on the left (N3/11) and right (N3/12) feature a fault memory. All the faults together can be read out only from the right ME-SFI control unit (N3/12).

Fault recognition

Signals above or below limit value
(open circuit in wiring, short circuit, sensors faulty)
Frequency and duration of fault
Illogical combination of signals
Closed loop (e.g. lambda control) at upper or lower control stop
Function chains with fault
Error messages via extremely fast data bus called CAN from control unit AT, ESP or IFRCL (Engine 120: Left ME control unit)

Fault storage

Faults detected for the first time are written to the fault memory first of all as "suspected fault" together with the fault freeze frame data. If the fault is not confirmed in the subsequent driving cycle, it is erased. If the fault is confirmed, it is stored together with its fault freeze frame data.

Faults which no longer occur are erased automatically from the fault memory after max. 40 warming-up phases .

Actuation of the CHECK ENGINE malfunction indicator lamp

Actuation of the engine diagnosis malfunction indicator lamp with low-emission EURO3/4

The indictor lamp in the instrument cluster comes on if the fault was already stored in the last driving cycle ( model year 1996: during the last trip ).

The "CHECK ENGINE" MIL or engine diagnosis at low emission EURO3/4 is quenching, if in the 3 driving cycles no fault is detected ( model year 1996: during the last 3 trips).

A warming-up phase is completed:

coolant temperature at start < 35 °C
Coolant has heated up to > 70 °C

A driving cycle (driving-cycle) is always based on an individual test and consists of

engine start
Individual test performed
engine turned off.

A trip ( model year 1996) is completed if

all tests and function chains of exhaust-relevant faults are performed at least once since engine start
Time after start > 20 minutes
Engine temperature greater than -7 °C
Engine speed > 500 rpm
500 rpm

Since the criterion of trip (model year 1996) has been replaced by the driving cycle (driving-cycle), faults are stored and the CHECK ENGINE indicator lamp (MIL) is actuated more rapidly.

Fault freeze frame data/operating conditions

The following data are stored if a fault is recognized:

Fault code
Vehicle speed
Engine speed
Coolant temperature
Intake air temperature
Intake manifold pressure
Engine load state
Ignition angle
Adaptation value of mixture formation
Status of lambda control
- Lambda control not enabled
- Lambda control enabled
- Lambda control inhibited (e.g. if fuel shut off)
- Lambda control inhibited (e.g. if fault detected)
- Lambda control without correction of O₂ sensor downstream of TWC
Further environmental conditions (e.g. fuel tank level, time after end of engine start, erase distance since last fault, erase counter readings for faults or fault frequency)

Function chains are test sequences activated by the ME-SFI control unit, e.g. for secondary air injection, exhaust gas recirculation, camshaft timing, purge system and leaktightness of evaporative emission control system.

Consequential faults

If a faulty signal is recognized and the corresponding fault code is stored, all the tests which require this signal as a comparative parameter, are ended. This ensures that no consequential faults are stored.

Emergency running

If a fault is detected, substitute values are formed. The indicator lamp in the instrument cluster only lights up, if the fault was already stored.

Readiness/function code

This code makes it possible to recognize that tests relating to fault recognition are in progress and the system is thus active. The code is set if the following tests are completed (result of test of no significance):

Catalytic converter efficiency
Regeneration
Secondary air injection
Exhaust gas recirculation
O₂ sensor upstream of TWC, signal
O₂ sensor upstream of TWC, sensor heater.

ME-SFI control unit afterrunning

After faults are erased, it is then necessary to wait until the processor has completed its afterrunning after the ignition is switched off. The time is dependent on the coolant temperature: at 80 °C approx. 4 seconds, at 20° C approx. 60 s and at -30° C approx. 150 s.

Fig 4: Identifying ME-SFI Diagnosis Fault Memory Function - Flow Chart

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Motor electronics control unit, location/task/ design/function		GF07.61-P-5000F
Pressure sensor location/design/task/function	with air injection Engine 104 and 111 Engine 112, 113 Engine 119, 120, 137 Engine 113 with CODE 479 (cylinder shutoff)	GF07.04-P-5014F
CHECK ENGINE malfunction indicator lamp, location/task/function		GF07.13-P-3144F
Engine diagnosis malfunction indicator lamp, location/task/function	EURO3/4 (Code 925/926 or standard)	GF54.30-P-4102A
ME-SFI fuel injection and ignition system diagnosis fault memory	List of all P-codes with possible causes of fault and references to remedy, Fault code descriptions with driving instructions
	Engine 104 Fault codes from P0000 to P0449	AD07.61-P-4000C
	Engine 104 Fault codes from P0450 to P1747	AD07.61-P-4000CA
	Engine 111 Fault codes from P0000 to P0699	AD07.61-P-4000D
	Engine 111 Fault codes from P0700 to P1747	AD07.61-P-4000DA
	Engine 112 with ME2.0 up to 31.5.00 Fault codes from P0000 to P0299	AD07.61-P-4000A
	Engine 112 with ME2.0 up to 31.5.00 Fault codes from P0300 to P0699	AD07.61-P-4000AA
	Engine 112 with ME2.0 up to 31.5.00 Fault codes from P0700 to P1747	AD07.61-P-4000AB
	Engine 112 with ME2.8 as of 1.6.00	AD07.61-P-4000AC
	Engine 113 with ME2.0 up to 31.5.00 Fault codes from P0000 to P0304	AD07.61-P-4000B
	Engine 113 with ME2.0 up to 31.5.00 Fault codes from P0305 to P0743	AD07.61-P-4000BA
	Engine 113 with ME2.0 up to 31.5.00 Fault codes from P0748 to P1747	AD07.61-P-4000BB
	Engine 113 with ME2.8 as of 1.6.00	AD07.61-P-4000BC
	Engine 119 refer to DMAN Engine, Volume 4 (9.5)
	Engine 120 Fault codes from P0000 up to P0209	AD07.61-P-4000F
	Engine 120 Fault codes from P0210 up to P0439	AD07.61-P-4000FA
	Engine 120 Fault codes from P0440 up to P0799	AD07.61-P-4000FB
	Engine 120 Fault codes from P0800 up to P1747	AD07.61-P-4000FC
	Engine 137	AD07.61-P-4000L