Bosch ME17.5

This section is underdevelopment. Feel free to add content. Please note we documented the ME17.5.6, some maps might not be present in the ME17.5

Reading, writing and checksums

For reading and writing procedures refer to Reading and writing ECU (ME7.1.1)

Most flashing tools fix checksums automatically, if you wish to fix them manually, you can use LSuite

Definition file can be found here. If you are getting started with tuning we recommend consulting : Introduction to tuning

Terminology (Acronyms)

Maps and variables names are identified under acronyms. Knowing some of them will be useful and will help you remember map names.

Here is a list of the useful ones.

List of acronyms

Acronym	German	English
A	Auslaßnockenwelle aktiv	Exhaust camshaft active
AB	Abregelfaktor	Derating factor for acceleration signal
AL	Adaptation Lastbereich	Adaptation load range
ASR		Anti-slip regulation
BB	Betriebsbedingungen	Operating conditions
BG	Berechnete Große	Calculated variable
BTS	Bauteilschutz	Component protection
CW		Code word
DFPM	Diagnose-Fehlerpad-Managers	Diagnostic Faulth Path Manager
DK	Drosselklappe	Throttle valve
DS-S		Pressure sensor (MAP) on intake manifold
E	Ersatzwert	Substitute value
ESUK	Einspritzung Ubergang Kompensation	Injection transition compensation
FA	Fahrer	Driver
FGR	FahrgeschwindigKeitsregler	Cruise control
FK	Faktor	Factor
FUEREG	Fullungreglers	Filling regulators
HFM		Hot film air mass sensor
KF	Kennfeld	Map
KL	Kennlinie	Curve
KN	Klopfereignis	Knock event
KR	Klopfregelung	Knock control
KRA	KR-adaptation	KR-Adaptation
KUPPL	Kupplung	Clutch
KW	Kurbelvelle Grad	Crankshaft degrees
LL	Leerlauf	Idle
LLK	Leerlauf und geoffneter kupplung	Idle and open clutch
LLRBB	Leerlaufregelung Betriebs dedingungen	Idle control operating conditions
LU	Laufunruche	Unstediness / roughness
LUAR	Laufunruhe-Abstandsmass-Referenzwert	Rough running distance measure value
LUR	Laufunruche-Referenzwert	Rough running reference value
MBVH	Missbrauchverginderung	Abuse prevention
MI	Motormoment indiziertes	Indicated torque
ML	Motor Luftmassendurchsatz	Engine air mass flow
MN		Minimum
MS	Massenstrom	Mass flow
MX		Maximum
N	Normierter	Normalized / NM
NW	Nockenwellen	Camshafts
NWS	Nockenwellengsteverrung	Camshaft control
OP	Optimales	Optimal
PVD	Pressure vor Drosselklappe	Pressure in front of DK
RL	relative Luft	Relative air filling (load)
RLMIN	Relative mimale Luft	Relative minimal air (filling)
SA	Schubabschatten	Fuel cut-off / overrun
SOL	Soll	Should
SW	Schlechtwegstrecke	Rough road
TPKHFM	TemperaturKorrektur HFM	Temperature correction HFM
TUM	Umgebungstemperator	Ambient temperature
TV		Delay time
UGD	Ungedroselt	Unthrottled
V	Verzogert	Delayed
WDK	DK-Winkel	DK angle
WKR	Winkelspatverstellung	Angle retard KR
WL	Warmlauf	Warm up
ZUL	Zulassig	Allowed limit
ZW	Zundungs Winkel	Ignition angle

Engine management

The ME17.5 use a TC1766 micro-controller. The ME17.5.6 use a TC1767 micro-controller. The program memory and the maps are both stored into the MCU which defers from the ME7.1.1 that have two chipsets, one for the MCU and an extermal memory chipset to store the maps.

There is no public funktionsrahmen for the ME17.5. You can use the MED17.5 Funktionsrahmen which will have some difference regarding injection as the MED17 use direct injections strategies while the ME17 use ported injection. For the missing modules, you can refer to the ME7.5 Funktionsrahmen.

The ME17.5.6 have some differences versus the ME17.5, extra modules, extra strategies and different map name. You can refer to the MED17.1.62 funktionsrahmen

This ecu is load-dependent. The driver request a torque, that torque is then converted to a load request and the ECU will target the requested load.

Engine load

The ME17 do not use a MAF to measure the air mass, the air mass is calculated based on the intake manifold pressure and intake air temperature. The conversion factor fupsrl convert the intake manifold pressure into load. The map KFDPBRWE can be used to bring correction to fupsrl.

MAP sensor scaling

If you fit a different MAP sensor, you can alter those two map to get the proper sensor scaling:

DSSGRAD : Gradient for pressure sensor intake manifold pressure
DSSOFS : Offset for pressure sensor intake manifold pressure

Requested load

The ME17 have the following logic flow : the driver request a desired traction torque, torque loss and friction are added / compensated to the torque request. Then the ECU ensures the torque request does not exceed the maximum. Then based on the maximum torque, we get a relative normal torque request (0-100%). The normalized torque is then processed into a map that will output the requested load. The ECU will use strategies to reach that load. (Throttle opening, ignition advance, air fuel mixture, etc.)

The following maps corresponds to the desired traction torque depending of the current gear (manual) or selected driving mode (auto) :

AccPed_trqEng1_MAP : 1st gear (leading) desired traction torque from engine speed and APP_rUnFlt
AccPed_trqEng2_MAP : 2nd gear (leading) desired traction torque from engine speed and APP_rUnFlt
AccPed_trqEng3_MAP : 3rd gear: (advanced) traction request torque from engine speed.
AccPed_trqEng4_MAP : 4th gear: (advanced) traction request torque from engine speed.
AccPed_trqEngRev_MAP : Driving behavior map reverse gear engaged
AccPed_trqEng0_MAP : start map

You can use the same values for all of those maps. If the engine produces more torque, you will need to edit those accordingly. Values are in nm.

The following map corresponds to the accelerator pedal in function monitoring :

MoF_trqEngAPP_MAP : Accelerator pedal map

Again, if the engine produces more torque, you will need to alter this map. You can also edit the above maps if you wish to change the profile or the response of the accelerator pedal.

The following maps are used for torque reserve, demand and losses:

MoF_trqDesAlt_MAP : electrical consumers in function monitoring (based on temp)
MoF_trqDrag_MAP :friction losses in function monitoring (based on temp)
ACComp_trqStatPres_MAP : static torque based on AC pressure
ACComp_trqStatTemp_MAP : static torque based on intake air temperature

The constant MoF_trqNorm_C represents the maximum indicated torque for torque normalization (in nm). The constant MoX_trqEngAPPMax_C can be use to determine the maximum requested torque in sport mode (in mm).

Normalized torque request to engine load

The map KFMIRL (Map for calculation of target filling) convert the normalized torque request into engine load (The map have more resolution in ME17.5.6 ECUs).

The map KFMIOP is the inverse of KFMIRL, it is used by the ECU for fast calculation to convert engine load into torque. (The map have more resolution in ME17.5.6 ECUs)

In the case of forced induction, there is a simple formula that give an approximate absolute pressure value based on the load request :

$10\times {\bigl (}load)+300$

You can then subtract the result by one atmosphere (1 bar) to get the relative boost pressure.

Here is an example with 190 load, 10 * 190 + 300 = 2200mbar in absolute, which would be 1200mbar in boost. In psi, that would be approximately 17 psi.

Fuel mixture control

Injector scaling

TVUBAT : Battery voltage dependant delay time (Injector dead time depending of voltage level)
KRKATE : Conversion of relative fuel air mass into effective injection time (See formula below)
FKKVS : Correction factor fueling system (Could also be called injector linearization map)

If you fit aftermarket injectors, ensure you have the specs for the injector dead time, as it is going to make scaling easier. Then calculate the KRKATE with the injector flow characteristic (at 4 bars, most injectors are rated at 3 bars). Once done, you can set FKKVS to 1 and edit the correction factor according to the STFT. (See below how to disable LTFT)

KRKATE Calculation

The following formula is taken directly from the funktionsrahmen.

The variables :

rho0Luft = 1.293 g / dm³ (Air density at 0°C and 1013hPa)
Vhzyl = dm³ (Displacement of a cylinder in dm³)
Qstat = g / min (Valve constant at n-heptane)
1.05 = Valve correction for gasoline
Lst = 14.7 (Air ratio for lambda)
NormK = 0.00001667 min / ms (Unit customization)

The formula :

$KRKATE={rho0Luft\times Vhzyl \over 100\times Lst\times NormK\times 1,05\times Qstat}$

Simplified formula for gasoline :

$KRKATE=50.2624\times displacement\;of\;a\;cylinder\;in\;dm^{(3)}/valve\;constant\;h-heptane$

You can also use this spreadsheet and fill in the information (has provision for ethanol content) : KRKATE calculator updated.xlsx

Disabling LTFT

Set NOLRA to 39. When you are done with scaling injectors, you can put back the long term fuel trim by setting NOLRA to 132.

Controlling air fuel ratio

Using LAMFA

You can use LAMFA (lambda driver request) to enrich the mixture at WOT.

TLAFA : Delay time until lambda driver request active (Set to 0 for quicker lambda change)
ZKLAMFAW : Time constant filtering enrichment by driver (Max out for quicker lambda change)

Using BTS (Lambda component protection)

The BTS offers more resolution than LAMFA. BTS is originally intended to enrich the fuel mixture when the exhaust temperature exceeded a threshold set by the manufacturer. We can reduce one of the threshold to ensure the ECU goes into BTS as soon as the engine is running.

To force the ECU into BTS, you could set KLTIKBTSMT to 0

Use the following map to set the lambda ratio : KFLBTS

Do not forget to lower KFLBTSBG (minimum lambda target for BTS) and LALIUSMN (minimum measurable lambda) if you plan to enrich the AFR further than the stock limits.

Fuel cut-off on deceleration

If you want to have crackle on deceleration, you can use the delay time for overrun fuel cut-off in the following map : KFTVSA

Ignition

Ignition advance

KFZW : Ignition timing map
KFSZMN : map with permanently latest possible ignition
KFZWMN : minimum ignition angle
KFZWMNST : minimum ignition angle for start and post-start
KFZW_UM : map of optimum ignition angle in function monitoring (increase this map to avoid advance interventions from the ECU)

Ignition coil closing time

KFSZMX : maximum closing time
KFSZMN : maximum closing time

Increase closing time on high voltage for forced induction application. The increase of pressure in the combustion chamber could require more charging / closing time.

Knock monitoring

KFDZWKG : ignition angle correction by shifting the knock limit (Set whole map to zero for better ignition tracking)
UDKSV6ON : upper reference voltage threshold knock sensor diagnosis (increase threshold for forced induction application)
KFKRFKN : retardation per knock event

In forced induction applications, increasing retardation per knock event is a safe measure to prevent more knock events from occurring, which results in a better ignition advance. For example, if a knock event occur and we pull 3 degrees and it still knocks, we would be pulling a total of 6 degrees. If we had pulled 4 degrees on the first knock event instead of 3 degrees, this could have been enough to prevent a second knock event. This way, we would end up pulling a total of 4 degrees instead of 6 degrees, giving us an extra 2 degrees in ignition advance ; resulting in more torque.

Variable intake cam

KFNWSE : map for camshaft spread (intake)

Use this map to correct torque loss due to VE change to the engine. (ex. intake manifold with different runner length)

Miscellaneous

Engine speed limiters

Please note map name differs from ME17.5 and ME17.5.6.

For ME17.5.6, limiters would start with HLSDem_nMax. For ME17.5, you can search for maps / constants that contains the key word NMAX.

Vehicle speed limiter

LLim_vMaxFix_C : vehicle speed limiter (max out to disable)

Brake boosting / left-foot braking

Brk_SRC.uMax_C : max voltage (Set to 6400mv)
AccPed_nMinNoBrkVelHi_C, AccPed_nMinNoBrkVelLo_C, AccPed_nMinBrkAPP_C, AccPed_nMinBrk_C, APP_nLim_C (Set to 9000rpm, over nmax)
Brk_uTransf_CUR : Set whole map to 0, set highest value of axis to 6400mv
Brk_swtRedSensPrs_C : Set to 0

Cat delete, o2 delete

CWKONABG : code word for exhaust gas treatment configuration - Set to 0
CWPSHSHE : code word for output stage diagnosis - Set to 0
TKHMXFHO : maximum switch on time of the cat heating (Zero out)
DFES_Cls.DFC_KAT_C : set to 0

Disable EVAP (N80)

CDTES : switch off code word for tank ventilation diagnosis - Set to 0
CDLDP : code word LDP diagnosis - Set to 0

Reducing rev-hang (manual gearbox)

Reducing the minimum filling reduces the rev-hang. There is probably an alternative to this method, but it has proven to be efficient.

RLMNN : characteristic minimum filling
RLMNSAN : characteristic minimum filling in the overrun

"Pop and bangs"

Increase delay time for overrun fuel cut-off in KFTVSA
Retard permanently latest possible ignition advance in the low load range in the following map : KFZWMS

Forced readiness

DSMRdy_X.PID1ForceLowMsk_C : application parameters for readiness - Set to 4278707456
DSMRdy_X.PID41ForceLowMsk_C : application parameters for readiness - Set to 517376

The logic is to set bit 0-7 to 0. This force readiness for catalyst monitoring, heated catalyst monitoring, EVAP, SAI, AC, O2, O2 Heater, EGR.

Forced induction

The following maps / constants will need to be modified to allow for more pressure tolerance in the intake manifold :

UDSUMN : minimum voltage for diagnosis of pressure sensor (Zero out)
UDSUMX : maximum voltage value for diagnosis of pressure sensor (Max out)
PSRMX : upper pressure threshold for range check (Max out)
DPUSINIMX : tolerances between pini_w and ambient pressure (Set to 1000hPa)
DPSRPUMIN : delta intake manifold pressure to minimum mod. (Set to 500hPa)
DPSRPUMN : delta intake manifold pressure to minimum mod. (Set to 500hPa)
FPSPULSMX : factor increased intake manifold pressure due to pulsations max (Max out)
DPTPSRMX : max tolerance of the intake manifold pressure sensor (Max out)
PSREMX : max substitute value for intake manifold pressure (Max out)

The following maps / constants will need to be modified to allow for increased load (Some map might not be present in ME17.5 ECUs):

MoF_ctDebAirMs_C : maximum permissible time for large deviation between rl_w and rlp_w in the RT (Max out)
MoF_nAirFilgPrdc_C : speed threshold for UFGKC (Set above NMAX to disable)
NGKC_UM : speed threshold for UFGKC (Set above NMAX to disable)
NMODC_UM : speed threshold for UFMODC (Set above NMAX to disable)
NRKTI_UM : lower speed threshold for rkti plausibility (Set above NMAX to disable)