E30/E28: Adjusting AFM (Air-Flow Meter) - change air/fuel rich/lean mixture

 ** ADJUST YOUR AFM SETTINGS AT YOUR OWN RISK **

This is for BOSCH AFM units, fitted to most E30 and other BMWs fitted with Bosch Motronic or Jetronic injection systems.

The AFM, or Air Flow Meter, is a metal flap that is drawn open by air entering the engine and the position of the flap tells the ECU how much air is coming in so it can inject the right amount of fuel. The stock parameters for the AFM are set at the factory and unique to each car and BMW recommend that these settings should NEVER be adjusted... so do it at your own risk!!

Why would the AFM need adjusting??

• You have done a ‘gas-test’ and the results show your car is running rich (too much fuel for amount of air) or lean (too much air for the fuel being supplied) and wish to adjust for emissions / fine-tuning purposes.
• You have an air leak after the AFM, so more air is getting in than the ECU is supplying fuel for and the engine won’t run, especially when cold.
• You have an over-fuelling problem where too much fuel is being supplied for the amount of air and flooding the engine.

Adjusting the AFM in the second two instances is a quick and dirty way to get your car running well enough to drive it, but is not a long-term fix for an underlying problem, so bear this in mind before messing with the AFM.

BMW MOST Bus - Troubleshooting Guide [Vlad on MCA]

 Great guide to the BMW MOST Bus (Media Oriented Systems Transport), used in all BMWs with fibre-optic connectivity. It covers what it is and what it does, as well as troubleshooting a lot of associated problems with these complex systems. It is from Vlad at MCA.org and can be found here: 

https://mca.electricmura.ro/en/blog-bmw-most-troubleshoot/

BMW Bosch L-Jetronic Fuel Injection - Strip-Down / Maintenance Guide + Diagrams [E30, E21, E28]

Throttle Housing:
1. Disconnect the cables (1, 2 or 3) as applicable - Fig. 1.
2. Pull off the vacuum hoses, the coolant hoses (1 and 2) - allowing the coolant to drain - and the air hoses (3 and 4) from the throttle housing - Fig. 2.
3.Remove the vacuum hoses (1 and 2), and the air hose (3) and pull off the multi-pin plug (4) - Fig. 3.
4. Remove the fixing nuts and take off the throttle housing. Do not separate the throttle switch from the housing, as a special gauge will be required to adjust it when refitting.
5. Refitting is a reversal of removal. Use a new gasket and bleed the cooling system.

Throttle Vacuum Control:
1. Pull off the hose (1), release the nut (2) and remove the vacuum control (3) - Fig. 4.
2. When refitting, adjust dimension (B) to between 32.8mm and 33.2mm (1.291" and 1.307") using screw (4).
3. Adjust dimension (A) to between 2.6mm and 3.0mm (0.102" and 0.118") using screw (2) - Fig. 5.

Control Unit:
1. Open the glove compartment and pull the pins from the retaining straps.
2. Remove the screws and place the glovebox cover to one side.
3. Depress the retainer (1) and pull out the multi-pin plug (2) - Fig. 6. Remove the control unit.

Air-flow Sensor:
1. Release the clamp and pull the duct from the air-flow sensor.
2. Disconnect the multi-pin plug, unscrew the fixing nuts and withdraw the sensor.
3. Refitting is a reversal of removal. Renew the seal if necessary.

Temperature Time Switch:
1. Pull off the plug, then unscrew and remove the switch.
2. Refit the switch using a new sealing washer.

Coolant Temperature Sensor:
1. Pull off the plug and unscrew the sensor. Refit using a new sealing washer.

Cold Start Valve:
1. Pull off the plug (1) and disconnect the fuel line (2) - Fig. 7.
2. Unscrew the mounting bolts (3 and 4) and withdraw the valve.
3. Use new seal when refitting.

Fuel Injectors:
1. Unscrew the four injection tube bolts and push the tube upwards until the fuel injectors have cleared the guide in the intake manifold.
2. Pull off the plug (1) and take out the circlip (2) - Fig. 8.
3. Take off the fuel injector.
4. Refitting is a reversal of removal; use new O-ring seals.

Throttle Shaft Return Springs:
1. Disconnect the throttle, kick-down and cruise-control cables. (The latter two where applicable.)
2. Remove the retainer (1), washer (2) and disconnect the linkage (3) on the lever (4).
3. Raise the lever and turn it to relieve the spring tension.
4. Remove the lever.
5. Remove the spring.
6. Disconnect the spring (1) and unscrew the nut (2) - Fig. 9.
7. Remove the washer (1) and lever (2) - Fig. 10.
8. Remove the sleeve (1) and spring (2) - Fig. 11. - also the wave washer.
9. Reassemble in the reverse order to dismantling and adjust in the following way - Pull off the tamperproof lock (1) and loosen the screw (2) until the lever (3) no longer rests on the screw - Fig. 12.
10. Place a finger on the lever and tighten the screw until the lever just begins to move. Turn the screw a quarter-turn more and refit the tamperproof lock.
11. Adjust the throttle, kick-down and cruise-control cables (where applicable).

Injection-system trouble-shooting guide here - https://www.beemerlab.org/2020/12/bmw-bosch-fuel-injection-system-trouble.html

Bosch L-Jetronic injection-system overview / diagram here - https://www.beemerlab.org/2019/11/e30e28e34-bosch-l-jetronic-fuel.html

E21/E12/E28: Bosch K-Jetronic Fuel Injection System Diagram / Explanation

Two types of fuel injection system are fitted. E21 3er 323i models are equipped with the Bosch K-Jetronic system, whereas E30 3er 320i and 325i models are fitted with the Bosch L-Jetronic system. This article covers K-Jetronic injection for E21 models, also injected E12 and early E28 5er. For L-Jetronic in E30 models, also later injected E28 5er, see THIS ARTICLE.

K-Jetronic Operation:
Fuel is drawn from the fuel tank by an electrically-operated pump and is then fed, via a pressure reservoir and filter unit, to the fuel distributor-unit. The fuel is then pumped direct to the fuel injectors which are located near the inlet valves, but mounted in four induction-manifold branches. The system is continuous acting type and the amount of fuel admitted to the injectors, by the fuel distributor, is governed by a pivoting baffle-plate mounted in the air-intake. Air drawn into the engine lifts the baffle-plate and this action moves a metering shuffle-valve in the fuel distributor. The ratio of air to fuel is thus controlled to a fine degree. After the mixture is drawn into the cylinder, the normal four-stroke combustion cycle takes place.

The fuel is maintained at a constant pressure by a pressure-regulator incorporated into the fuel distributor-unit, excess fuel being diverted through a return-line back to the fuel tank.

For cold starting, a solenoid valve injects fuel into the air-intake for a period determined by the coolant temperature. In addition, a temperature sensitive (warm-up) regulator, working in conjunction with an additional air slide-valve, is connected to the fuel distributor-unit and has the effect of increasing the amount of fuel delivered by the injectors. Later models are fitted with a throttle bypass-valve in place of the additional air slide-valve. On some specific versions this valve is coolant-heated.

A normal type throttle butterfly-valve, mounted between the baffle-plate and the cylinders, is connected to the accelerator pedal linkage. These constant flow injection systems work in a similar manner to a carburettor, vaporising fuel in the inlet-manifold and metering it into the engine.

E30/E28/E34: Bosch L-Jetronic Fuel Injection System Diagram / Explanation

Two types of fuel injection system are fitted. E21 3er 323i models are equipped with the Bosch K-Jetronic system, whereas E30 3er 320i and 325i models are fitted with the Bosch L-Jetronic system. This article covers L-Jetronic injection for E30 models, also later injected E28 and early E34 5er  For K-Jetronic in E21 models, also injected E12 and early E28 5er, see THIS ARTICLE.

K-Jetronic Operation:
In fuel injection systems of Bosch L-Jetronic type, the volume of air drawn in by the engine is measured.

Each cylinder has its own independent injector.

An additional air slide-valve bypasses the throttle butterfly stub pipe and controls the additional air volume required when the air is still cold. When the engine is warm, idle speed airflow control is by means of another bypass around the throttle butterfly.

Fuel supply and pressure is provided by an electric pump with an inline filter and pressure regulator.

The volume of air drawn into the engine is measured by the air flow meter and this is converted into an electric impulse and transmitted to the control unit. A calculation is made to determine the quantity of fuel to be injected (based upon the engine running speed) into each cylinder.

Automatic cold-start and warm up devices are incorporated into the system with corrections made to the amount of fuel delivered for idle-speed and full-load by contacts in the throttle butterfly switch. When the engine is on the overrun and throttle is closed, due delivery is shut off completely.

The electronic control unit processes information from the various engine sensors and sends an impulse to the electromagnetic fuel injectors, telling them to open for a precisely defined period and deliver a set amount of fuel for each ignition. This is how most modern fuel-injection systems (with the exception of direct-injection systems) work.

BMW BUS System Troubleshooting

Interesting and highly informative BMW training manual on troubleshooting the BUS system fitted to cars built from the late '90s through the 2000s. Detailed guides on design, diagnosis and repair of the original BMW CAN-BUS systems.

https://drive.google.com/uc?export=download&id=1vIxKdCSqhcQqEKfE_VTRVw7PWJuP6rNE

BMW BUS SYSTEM TROUBLESHOOTING:

1. Introduction

2. Definitions

3. Controller Area Network (CAN bus):

• Introduction
• CAN bus topology
• Troubleshooting the CAN bus

4. Diagnosis Bus (D-bus):

• Introduction
• D-bus topology
• Troubleshooting the D-bus

5. Information and Body Bus:

• Introduction
• I/K bus topology
• Troubleshooting the I/K bus

6. Peripheral Bus (P-bus):

• Introduction
• P-bus topology
• Troubleshooting the P-bus

7. Motor Bus (M-bus):

• Introduction
• M-bus topology
• Troubleshooting the M-bus

8. Review Questions

All models using Bus System from model year 1991 onwards.

This module discusses:

• Advantages of using bus systems in a vehicle.
• Various bus systems used in most BMW vehicles.
• Operating principles of a serial bus.
• Methods of troubleshooting bus lines using the diagnosis program.
• Distinguishing a correctly operating bus line on an oscilloscope.

Have fun!

DIS v57 + INPA / EDIABAS 6.4.3 Installation + Guide

Download Links [MediaFire]:

BMW INPA / EDIABAS 6.4.3 + Install Files etc. [1.1GB]

BMW DIS v57 / SSS v32 Installer Files [6.7GB]

**You will need BOTH parts to fully install DIS v57**

You will need a laptop with USB running Windows XP or Windows 7.

You will need a USB-OBD cable optimised for post-2005 BMWs. An older cable can be modified by removing the solder-bridge between OBD pins 7 and 8 - a guide is here.

GUIDE:

Unpacking Files:

• Unpack the 2 .rar files into a new folder.
• Where the contained instruction file mentions unpacking files from CD1 and CD2, all the .rar files for both CDs are contained in the one 6.7GB download.  

Installation:

• If upgrading from DIS v44, install the files into the same folder and overwrite existing files.
• The instructions cover Windows XP, but files for Windows 7 and 64-bit, along with instructions for that are provided in a folder marked OTHER.

Further installation and troubleshooting instructions [getting the virtual machine / network bridge / ports etc. working] can be found in my prior DIS v44 guide: HERE.

BMW Diagnosis Abbreviations for E38, E39, E46, E53 X5

These are the abbreviations used when diagnosing pre-iDrive BMW BUS-systems, starting with E38 7er, through E39 5er, E46 3er and E53 X5. For iDrive models E65, E60/61, E90 etc. see this post.
They're from a great thread by kneescrap on BimmerForums.com - [http://www.bimmerforums.com/forum/showthread.php?1599329-BMW-abbreviations].

A - processed vehicle speed signal
A - "out" (Aus)
AB - Airbag
ABL - Brake system warning Lamp (2 color)
ABS - Anti-lock Braking System
AC - Air Conditioning (from ETK)
ACC - Active Cruise Control
ACS - Active Comfort Seats
ADB(X) - Automatic Differential Braking
ADS - engine intake air control
ADV - windshield wiper pressure control
AEGS - Automatic Electronic Gearbox Control (also EGS)
AFM - Air Flow Meter
AGD - suction silencer (from ETK)
AGR - emission reduction
AGS - Adaptive transmission control
AG - Automatic Gearbox (transmission)
AHK - Active rear-axle Kinematics
AHK - trailer hitch (from ETK)
AHM - trailer Module (not for US models)
AHPS - Advanced HPS
AIC - Automatic Interval Control (rain sensor)
AKF - activated carbon canister (from ETK)
AKS - Active head restraint
AKS - pressure regulating device (from ETK)
ALC - Automatic Light Control
ALR - Automatic Lamp Range Adjustment
AMM - Air Mass Meter
AMP - radio system AMPlifier
ARI - car radio information system (from ETK)
ARS - Active Roll Stabilization
ASC - All Season traction
ASC-EZA - ASC w/ engine timing and injection intervention
ASC+T - ASC+ Traction control
ASK - Audio System controller (Kontroller)
ASR - self starter block relay (from ETK)
AST - Automatic Slip control (marketing term)
AT - remanufactured part (from ETK)
AT - Antenna (from ETK)
ATF - Automatic Transmission Fluid (from ETK)
ATL - exhaust gas turbo charger (from ETK)
AUC - Automatic air recirculation
AUT - AUTomatic transmission (from ETK)
AVT - Antenna amplifier Tuner
AZD - tightening torque specifications (in TIS)
A/D – Analog/Digital

B - Benzene (gasoline)
BAT - BATtery (from ETK)
BC - Board Computer
BC1 - Body Controller 1
BL - Brake Light (from ETK)
BLS - Brake Light Switch
Bluetooth - A wireless interconnection technology that automatically recognizes and communicates with components (such as cell phones, headsets and computing devices) when brought into close proximity (generally 30 feet or less).
BMBT - Board Monitor
BS - Block diagram
BST - Battery Safety Terminal
BVA - Brake pad wear indicator (from ETK)
BZM - center console control center
BZMF - center console control center, rear

CAN – Controller Area Network (Multiple ECU Controller)
CAN-Bus - Controller Area Network (bus)
CANH-Bus - CAN bus, High
CANL-Bus - CAN bus, Low
CANP - fuel tank ventilation valve
CAS - Car Access System
CBC - Corner Braking Control
CBS - Condition Based Service
CCM - Check Control Module
CD - Control Display
CDC - Compact Disk Changer
CDS - CD player (from ETK)
CEL - CELsius (from ETK)
CIM - Chassis Integration Module
CO - Carbon monOxide (from ETK)
COMBI – Electronic Instrument Cluster
CON - CONtroller
CU - Copper (from ETK)
CVM - Convertible top Module
CVT - Constantly Variable Transmission
CW - drag coefficient (from ETK)
CWP - Cold Weather Package

D1 - Xenon light/ gas discharge (from ETK)
D-Bus - Diagnosis bus (same as TXD)
DBC - Dynamic Brake Control
DBS - Dynamic Braking System
DCS - Dealer Communication System
DE – Diagnostic Unit
DD - Dynamic motor Drive
DDE - Digital Diesel Electronics
DIN - German industrial standards
DIS - Diagnosis and Information System
DISA - Differential air intake control
DIVA - continuously variable length intake runners
DK - throttle housing/valve
DKB - throttle w/ brake intervention
DKE – Throttle Increase
DKI - throttle position
DKR - throttle reduction
DKT - throttle position signal
DKV - preset throttle position value
DME - Digital Motor Electronics
DM-TL - Diagnostic Module Tank Leakage
DOHC - Double Over Head Camshafts (from ETK)
DS - gasket set (from ETK)
DSC - Dynamic Stability Control
DSP - Digital Sound Processing
DTC - Diagnostic Trouble Code (SAE)
DTC - Dynamic Traction Control
DWA - theft deterrent system
DWS - tire pressure Warning System
DZM - revolution counter (from ETK)

E - "in" (Ein)
EBA - EinBau Anleitung (translated Installation Instructions). This is a CD-ROM with installation instructions for various options and upgrades.
EBV - Electronic Brake force proportioning
ECE - European market version (from ETK)
ECM - Engine Control Module (SAE term)
ECU - Electronic Control Unit
EDC - Electronic Damper Control (from ETK)
EDR - Electronic throttle control
E-KAT - Electrically heated catalytic converter
EZA - see ASC-EZA
ECM - Engine Control Module (SAE term)
ECO - Controller for I-Drive system
EDC - Electronic Dampening Control
EDC-K - Electronic Dampening Control - Continuous
EDK - Electronic throttle valve
EDS - pressure regulator
EFH - Electric window lifter (from ETK)
EGS - Electronic transmission control
EH - Electronic-Hydraulic
EHC - Electronic Height Control
EKM - Electronic body Module
EKP - Electric fuel Pump
ELV - Electronic steering lock
EM - Electro-Mechanical
EMF - Electro-Mechanical parking brake
EML - Electronic Motor Load regulation
EMV - Electro-Magnetic sensitivity (from ETK)
EO - component location
EPC - Electronic Parts Catalog (also ETK)
EPROM - Erasable/ Programmable chip Memory (from ETK)
ETK - Electronic parts catalog (also EPC)
ETM - Electrical Troubleshooting Manual
ESS - Electronic anti-theft device
EV - injection Valve
EWS - Electronic drive-away protection

FB - Function description
FBC - Fading Brake Control
FBD - remote control services
FBZV - radio frequency locking system
FGR – Vehicle Speed Control (Cruise Control)
FH - window lifter
FHK - rear Heater/ air conditioner
FLC - automatic Light Control
FRU - Flat Rate Unit
FS – Crash Sensor
FZV - central lock receiver

GAL - speed dependent sound volume
GM - General Module
GMR - yaw moment control
GPS - Global Positioning System
GRII - cruise control
GRS - rotation Rate Sensor
GS – Belt Tensioner
GWK - torque converter lock-up control

H - "rear" (Hinten)
H2 - Xenon headlights
HA - rear Axle (from ETK)
HC – Hydro Carbon
HD - Heavy Duty (from ETK)
HDC - Hill Decent Control
HFM - Hot Film air mass Meter
HG - manual Gearbox (transmission)
HKL - Hydraulic trunk lid Lift
HLM – Hot Wire Air Mass Meter
HPS - Head Protection System
HR - Heater control (from ETK)
HVA - Hydraulic Valve Adjuster (from ETK)
Hz – Hertz (Cycle)

I-Bus - Information bus
IB - Interior lighting control signal
IHKA - automatic Heating and A/C
IHKAF - IHKA w/ micro filter
IHKR - regulated Heating and A/C
IHKRF - IHKR w/ micro filter
IHKS - standard Heating and A/C
IHPD - Internal High Pressure Deformation
IHR - Integrated Heater control (from ETK)
IKE - Instrument cluster Electronics
ILH - Interior Lighting, rear
ILV - Interior Lighting, front
IMS - Instant Mobility System (from ETK)
IR – Infrared
IRS – Infrared Locking System
ISC – Idle Speed Control
ISIS - Intelligent Safety Integration System
ISN - Individual Serial Number
ISOFIX - standardized mounts for child restraints
ITS - head airbag assembly/ Inflatable Tubular Structure
IVM - Integrated power supply Module

K-Bus - body bus (Karosserie)
KAT - catalytic converter
KATON - converter creating (signal)
KD - Kick-Down
KDS - Komputer Service Desk (Translated Computer) A CD-ROM that inlcudes the defect codes and flat rate labor units BMW allows for the warranty repair of defects.
KHI - interface for headphones
KL - terminal designation
KL15 - run bus (ignition switch run position)
KL30 - battery bus (hot at all times)
KL31 - ground bus (chassis ground)
KL50 - start bus (ignition start position)
KLR - accessory bus
KO - compressor "on" signal
KOMBI - instrument cluster
KOREL - compressor relay signal
KR – Contact Ring
KSK - Knock Sensor
KVA - fuel consumption signal/value
KW - crankshaft
KW - KiloWatt (from ETK)

LCM - Lamp Check Module
LDP - Leak Diagnosis Pump
LEV - Low Emissions Vehicle
LEW - Lateral acceleration sensor
LHD - Left-Hand Drive (from ETK)
LKM - Lamp control Module
LL - closed throttle
LM - Light Module
LMM - air flow meter/sensor
LMR - Light alloy wheel
LRA - vertical headlight aiming
LSM - steering column memory
LSZ - Lamp Switching center
LVA - air supply system (for EHC system)
LWR - vertical headlight aim control
LWS-5 - steering angle sensor

M-Bus - IHKA/IHKR stepper motor bus
MAL - center armrest
MBC - Maximum Brake Control
MDK - Motorized throttle valve/system
MFL - Multi-Function steering wheel
MFC - Multi-Function Controller
MFU - Multi-Function Clock
MID - Multi-Information Display
MIL - Malfunction Indicator Lamp (SAE), "check engine" Lamp
MIR - Multi-Information Radio
MMC - Multi-Media Changer
MoDiC - Mobile Diagnostic Computer
MOST-Bus - Media Oriented System Transport bus
MRS - Multiple Restraint System
MSR - engine drag torque Regulation
MV - Magnetic Valve (solenoid Valve)

n-ab - rotational speed, transmission (rpm)
n-mot - rotational speed, engine (rpm)
NAVI - Navigation module
NG - New Generation (as in N73 engine)
NG - tilt sensor
NOX - Nitrogen Oxides/ exhaust gas recirculation (from ETK)
NSD - rear muffler (from ETK)
NSL - rear fog Lamp (from ETK)
NSW - fog lamp (from ETK)
NTC - Negative Temperature Coefficient
NW - camshaft (from ETK)

OBC - On-Board Computer
OBD - On-Board Diagnosis (SAE)

P/N – Park/Neutral position
P-Bus - Periphery bus
PB - Pin assignments
PBS - Parts Bulletin System (in TIS)
PDC - Park Distance Control
PGS - Passive Go System
PM - Power Module
PP – Impact Pad
PTC - Positive Temperature Coefficient

RLS - Rain-Light Sensor
PWG - Pedal position sensor/ potentiometer
RA - Repair instructions (in TIS)
RAM – Random Access Memory
RAL - Aluminum wheels (from ETK)
RAL - standard color (from ETK)
RDC - tire pressure Control
RDS - Radio Data-broadcast System
RDW - tire pressure Warning
RHD - Right-Hand Drive (from ETK)
RM - Relay Module
ROZ - Research Octane rating/ fuel grade (from ETK)
RPA - tire puncture warning (from ETK)
RPS - Rollover Protection System
RS - Repair kit (from ETK)
RSW - back-up lamp (from ETK)
RXD - wake-up Diagnosis line
RZV - direct stationary ignition

SASL - Satellite, A-pillar left
SASR - Satellite, A-pillar right
SAV - Sport ACTIVITY Vehicle
SB - fuse assignments
SBE - Seat occupancy detector/sensor
SBFH - Seat module, passenger-side rear
SBSL - Satellite, B-pillar left
SBSR - Satellite, B-pillar right
SBT - SI techniques/ tech reference information (in TIS)
SCA - Soft Close Automatic/Actuator
SD - sliding roof (from ETK)
SD - silencer/ muffler (from ETK)
SE - Special Equipment (from ETK)
SES - voice recognition System
SFAH - Seat module, driver's side rear
SFZ - Satellite, vehicle center
SG - control unit
SGS - Seat integrated belt System
SHD - sliding/ lifting roof (from ETK)
SHD - Sunroof module (also SHDM)
SI - Service Information (in TIS)
SIA - Service Interval system (ver. I, II, III, IV, etc.)
SII - Service Interval Indicator
SIL - SILicon (from ETK)
SIM - Safety Information Module
SINE - Siren/tilt sensor
SKD - Steel sliding roof (from ETK)
SKHD - Steel sliding/ lifting roof (from ETK)
SM - Seat Module
SM/SPM - Seat/Mirror Memory
SMBF - Seat Module, passenger side
SMFA - Seat Module, driver's side
SMG - Sequential Manual Gearbox
SP - Schematic
SRA - headlight/fog light cleaning
SRS - Supplementary Restraint System
SSD - Steel sliding roof (from ETK)
SSH - Seat Satellite, rear seat
ST - connector views
Steptronic - transmission shift control
STVL - Satellite, left front door
STVR - Satellite, right front door
SVS - Speech processing System
SWR - headlamp cleaning system (from ETK)
SWZ - Special tool listings (in TIS)
SZL - Switch center, steering column
SZM - central switch center Module

TAGE - door handle Electronics
TCM - Transmission Control Module
TD - engine speed signal (ignition pulse)
TD - Technical Data (in TIS)
TDD - Technical Documentation Disk. Made availble to consumers and dealers by force of the DOT/EPA regulations for servicing the electrical and mechanical components of the emissions replated systems on the cars that are not on the ETM.
TE - fuel evaporation control
TEL - TELephone control unit
TEV - evaporative purge control
THZ - Tandem master cylinder (from ETK)
ti - Injector "on" Time (duration)
TIS - Technical Information System
TL - part throttle / load signal
TLEV - Transitional Low Emission Vehicle
TMBFT - door Module, passenger side
TMBFTH - door Module, passenger side rear
TMFAT - door Module, driver's side
TMFATH - door Module, driver's side rear
TP - Tandem Pump (from ETK)
TPS - Throttle Position Switch/Sensor
TR - engine speed signal (rpm)
TR - TRansistor (from ETK)
TRG - fuel level sensor (from ETK)
TRI - Technical Reference Information (also SBT)
TRS - battery isolation Switch
TSD - Torsional vibration dampener (from ETK)
TSB - Technical Service Bulletin
TSH - door lock Heating
TSZI - Transistorized coil Ignition system (from ETK)
TU - Technical Update (as in M50tu)
TXD - Transmitting Diagnosis line

U-batt - Battery voltage
U-vers - supply voltage
UERSS - rollover bar (from ETK)
URS - rollover protection System
USIS - Ultrasonic passenger compartment Sensor

V - "front" (Vorn)
V - vehicle road speed
VA - front Axle (from ETK)
VAT - front axle support (from ETK)
VANOS - Variable camshaft timing
VEP - distributor-type injection Pump (from ETK)
VID - VIDeo module
VL - full load (wide open throttle)
VSD - front muffler (from ETK)
VVT – Valve tronic

WBG - hazard warning switch (from ETK)
WIM - Wiper control Module
WK - torque converter lock-up clutch
WSS – Wind Shield (from ETK)
WT – Valve tronic control unit

Z - "central" (Zentrum)
ZAB - ignition fade-out (reduction)
ZAE - central Airbag Electronics
ZAS - ignition starter switch (from ETK)
ZGM - central Gateway Module
ZK - cylinder head (from ETK)
ZKE - central body Electronics
ZKH - cylinder head cover (from ETK)
ZMS - dual-Mass flywheel (from ETK)
ZV - central locking system
ZS - central lock (from ETK)
ZSD - center muffler (from ETK)
ZV - central locking system (from ETK)
ZVM - central locking Module
ZWD - idle control valve