Synonyms for aldl or Related words with aldl
Examples of "aldl"
Codes retrieved are still 2 digit codes which still require an
scan tool, a laptop and USB-
interface with a properly pinned J1962
plug, or a GM Tech II. Flash codes can be retrieved on 1994–1995 Corvettes by shorting #12-Vendor Option to #4 Chassis Ground.
was previously called Assembly Line Communications Link or ALCL. The two terms are used synonymously.
The pinout for the
connection on these cars is as follows:
on 1991 and later California emissions GM vehicles met the 1991 and later California OBD I communication standard. This does not mean that
is OBD I. OBD I was an early 1990s California-only mandate, not a United States federal mandate. It was not used on non-California emissions vehicles.
The earliest implementations of
were unidirectional and transmitted serial data at 160 baud using PWM. Some 160 baud models constantly transmitted sensor data on startup, while others started transmitting data when placed in diagnostic mode with a resistor connected to the
Note the difference in pin ordering between the connectors and the fact that the letter I is not used. Unfortunately, the definition of which signals were present on each pin varied between vehicle models. There were generally only three pins used for basic
—ground, battery voltage, and a single line for data—, although other pins were often used for additional vehicle-specific diagnostic information and control interfaces. No battery voltage is present in the 12 pin
was not a standard. It was actually extremely fragmented. The information exchange changed with each powertrain control module (aka PCM, ECM, ECU). A PCM integrates transmission and engine control on one Processing unit. ECM/ECU are engine control only with a separate TCM (Transmission Control Module) if needed. While
is the closest thing to standard onboard diagnostics prior to 1991
was not a standard.
was even fragmented within GM brands, models, and model years. Trim levels in the same model year, division, and nameplate can use different communications. Different versions presented differences in diagnostic jack pin-outs, data protocols, and data rates (this is the reason for the ″Mask″ files needed for aftermarket software communication). Earlier versions used 160 bit/s, while later versions went up to 8192 bit/s and used bi-directional communications to the PCM or ECM/TCM.
(Assembly Line Diagnostic Link) is a General Motors proprietary onboard diagnostic interface that started with the late 1970s and early 1980s CLCC (Closed Loop Carburetor Control) and early GM EFI systems.
The signaling of
is similar to the RS-232 serial data standard; differing in the voltages used to denote logical one (usually 0VDC) and logical zero (either +5VDC or +12VDC), and that unlike RS232, both transmit and receive functions are on the same conductor. Schematics are available on the internet for devices that can be used to convert the
voltages to that of the RS-232 standard, allowing the raw data to be read with a computer having a serial port and the proper software.
Some Asian, European, and North American diagnostic ports are sometimes incorrectly referred to as
. A small number of vehicles manufactured before 1996 from other manufacturers used the GM Delphi Electronics engine and powertrain controllers; however, these used a modified
communication protocol. Most did not and there was not a homogeneous name for these other proprietary diagnostic protocols and interface ports. Ford EEC, Toyota DLC, Chrysler, Nissan, Volkswagen, and others used their own onboard Diagnostics protocols and connectors, and are also not OBD I compliant outside California.
In both versions,
data is sent in a format unique to the model of ECU in the vehicle with little standardization between models, so a proper definition of the data is required to interpret it. Most professional scan tools require a large database of vehicle definitions.
Assembly Line Diagnostic Link or
was a proprietary on-board diagnostics system developed by General Motors prior to the standardization of OBD-2. For the assembly plant test system computer which was connected to this vehicle connector and known by the same name see the article IBM Series/1.
This system was only vaguely standardized and suffered from the fact that specifications for the communications link varied from one model to the next.
was largely used by manufacturers for diagnostics at their dealerships and official maintenance facilities. The connector is usually located under the dash on the driver's side of left-hand drive (LHD) vehicles, though this location was not standardized.
Multiple scanner software programs are available. TunerPro RT is one of the most flexible and most popular. It covers most US applications. 94-95 6.5 Turbo Diesel scanner software is also available Direct USB to
cables and even Bluetooth modules are available from suppliers like Red Devil River.
There's an appearance of standardization because the diagnostic jack didn't change over the years
was utilized by GM. GM North America used a proprietary 12 position Metripack 280 diagnostic jack. GM Australia Holden used a 6 position Metripack 280 diagnostic jack. The GM Europe Opel and Vauxall used a 10 position Metripack 280 diagnostic jack.
Later versions were bidirectional and operated at a much faster (but incredibly slow compared to today's standards) rate of 8192 baud. Implementations using the 8192 baud rate were primarily request-driven, meaning that the main diagnostic data was not transmitted until a request was made. Some idle data transmission of trivial parameters, however, existed in many vehicles. Bidirectional communication also allowed many other functions to be performed via
, such as actuator tests, parameter overrides, and in some cases even reprogramming of the ECU itself. Multiple devices could be placed on the
data line for primitive networking and communication. Many later 8192 baud vehicles, for example, had airbag control, ABS, and even climate control units sending data on the same serial bus.
Example systems and applications included Manufacturing Information Database (MIDB), Vehicle Component Verification System (VCVS) and Assembly Line Diagnostic Link (
). These systems were connected to plant floor devices and used in the realtime manufacture of vehicles. There was also a Time and Attendance (T&A) system connected to badge readers and employee turnstiles. Series/1 computers where also utilized in the early development of GM's Manufacturing Automation Protocol (MAP)
The MIL appeared in the early 80s along with computerized engine controls. Even the earliest systems, such as GM's CCC (Computer Command Control) system had self diagnosis functionality. When the computer detected a fault, it illuminated the MIL. Up until OBDII, on most cars the MIL could output codes, when two pins on the
are jumped, the light would flash the codes, for instance (blink) (pause) (blink) (blink) for code 12. Some manufacturers, such as Honda, retained this feature even after OBDII.
There were at least four different connectors used with
. General Motors implemented both a 5-pin connector and a 12-pin connector, with the 12 pin connector (Packard/Delco/Delphi part number 12020043) being used in the vast majority of GM cars. Lotus implemented a 10-pin connector. The pins are given letter designations in the following layouts (as seen from the front of the vehicle connector):
OBD 1.5 refers to a partial implementation of OBD-II which General Motors used on some vehicles in 1994 and 1995. OBD 1.5 is a slang term. GM did not use the term OBD 1.5 in the documentation for these vehicles; they simply have an OBD and an OBD-II section in the service manual. Most of these 1994 & 1995 vehicles were simply 8196 baud
serial data on the #9 vendor option terminal of the J1962 Jack that was formally adopted for OBD II starting in 1996.
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