Comparison of Leading Diagnostic Systems

If you looking to buy an OBD-II scanner, you'd probably be as confused as I was when I initially contemplated do so. In the realm of automotive diagnostics, the market offers a plethora of OBD-II systems, each vying for attention with unique features and capabilities. So let's embark on a constructive comparison of some prominent players in this arena: Launch, ODIS V23, VAS, Genuine Ross-Tech VCDS (VAG-COM), icarsoft, and the VAG Group Dealer Diagnostic Software.

1. Launch:

Launch stands out as a robust diagnostic system known for its user-friendly interface and broad compatibility across various vehicle makes and models. Its extensive database of diagnostic trouble codes (DTCs) and live data parameters makes it a versatile choice for technicians. Launch's continuous updates ensure compatibility with the latest vehicle systems, enhancing its utility for a diverse range of users.

2. ODIS V23:

ODIS (Offboard Diagnostic Information System) is the official diagnostic software for Volkswagen Group vehicles. Its seamless integration with VAG (Volkswagen Audi Group) cars provides in-depth access to manufacturer-specific systems. ODIS V23 excels in advanced coding and adaptation capabilities, making it a preferred choice for authorized dealerships and professional technicians dealing exclusively with VAG vehicles.

3. VAS (VAG Diagnostic Tool):

VAS, the VAG Diagnostic Tool, shares its roots with ODIS and is tailored for VAG Group vehicles. It offers comprehensive diagnostic functions, guided fault finding, and system-level adaptations. VAS is renowned for its accuracy and reliability in diagnosing intricate issues within VAG vehicles, catering to the discerning needs of dealerships and specialized repair shops.

4. Genuine Ross-Tech VCDS (VAG-COM):

The Genuine Ross-Tech VCDS, popularly known as VAG-COM, has gained a cult following among enthusiasts and professionals alike. Renowned for its detailed and customizable diagnostics, VAG-COM provides extensive control over VAG vehicle systems. Its interactive interface allows users to delve deep into coding and adaptations, making it a preferred choice for those who value precision and control.

5. icarsoft:

icarsoft offers a range of OBD-II diagnostic tools catering to various vehicle manufacturers. Its user-friendly interfaces and affordability make it accessible to a broad audience. icarsoft tools often feature comprehensive DTC libraries, live data streaming, and basic coding functionalities, making them suitable for both enthusiasts and independent repair shops.

6. VAG Group Dealer Diagnostic Software:

Designed for official VAG dealerships, the VAG Group Dealer Diagnostic Software is a comprehensive tool that provides unparalleled access to manufacturer-specific systems. Tailored for VAG vehicles, this software ensures accurate diagnosis, guided troubleshooting, and seamless integration with the latest advancements in VAG Group technology.

The choice between Launch, ODIS V23, VAS, Genuine Ross-Tech VCDS, icarsoft, and VAG Group Dealer Diagnostic Software hinges on specific user needs, vehicle preferences, and budget considerations. Launch excels in versatility, ODIS V23 and VAS cater to the intricate needs of VAG vehicles, Genuine Ross-Tech VCDS offers precision and customization, icarsoft provides affordability, and VAG Group Dealer Diagnostic Software ensures the highest level of integration for official dealerships. Evaluating the unique features of each system empowers users to make informed decisions based on their specific requirements within the diverse landscape of OBD-II diagnostic tools.

Unlocking the Mysteries of Automotive Diagnostics

Unlocking the Mysteries of Automotive Diagnostics

In the intricate world of modern automotive technology, the ability to diagnose and troubleshoot issues has become an indispensable skill for both mechanics and car enthusiasts. One of the key frameworks governing this diagnostic landscape is the Onboard Diagnostics (OBD) system, specifically the second iteration, OBD-II, which adheres to the standards set by the Society of Automotive Engineers (SAE).

SAE and OBD-II Standards:

The SAE plays a crucial role in establishing standards that govern automotive diagnostics. In the context of the VW Polo and many other vehicles, OBD-II is the standardized system designed to monitor and report the performance of various vehicle systems, ensuring compliance with emission regulations.

Stoichiometry and Emission Control:

Understanding stoichiometry is fundamental to comprehending OBD-II's role in emission control. Stoichiometry refers to the chemically balanced ratio of air to fuel necessary for complete combustion. OBD-II monitors this ratio through sensors, with the Oxygen Sensor System (OXS) playing a pivotal role in providing feedback to the engine control module (ECM).

EPC Light - Electronic Power Control:

One of the telltale indicators of an issue within the electronic realm of the VW Polo is the Electronic Power Control (EPC) light. This warning light illuminates when the system detects a fault affecting the engine's performance. The EPC system is responsible for managing the throttle, ensuring optimal power delivery and efficiency.

Check Engine Light and DTC Codes:

The infamous Check Engine Light (CEL) is another beacon of concern for drivers. When illuminated, it signals potential issues with the engine or emissions system. Diagnostic Trouble Codes (DTC), communicated through the OBD-II system, provide mechanics with specific information about the nature of the problem, allowing for a targeted and efficient diagnosis.

Limp Mode and Safety Features:

In the event of a critical issue, the VW Polo employs a safety feature known as Limp Mode. This mode restricts the vehicle's performance to prevent further damage, allowing the driver to reach a service center safely. Understanding the triggers for Limp Mode requires decoding the specific DTCs stored in the OBD-II system.

Sensors, Senders, and Actuators:

Central to the OBD-II system are an array of sensors and senders strategically placed throughout the vehicle. These components, such as the Oxygen Sensor, monitor various parameters and relay information to the ECM. Actuators, controlled by the ECM, respond to these inputs by adjusting engine functions to maintain optimal performance and emissions.

16-Pin OBD-II Connector:

Mechanics rely on the 16-pin OBD-II connector to interface with the vehicle's diagnostic system. This standardized connector provides access to the wealth of information stored within the OBD-II system, facilitating precise diagnosis and troubleshooting.

Automotive Acronyms:

Navigating the world of automotive diagnostics often involves deciphering a myriad of acronyms. From EPC to DTC,to HVAC, to OXS, to EGR and beyond, mechanics adeptly use these shorthand terms to  efficiently communicate and clients and pinpoint issues with precision.However, it can confuse the hell out of them.

Delving into the realm of automotive diagnostics for the VW Polo unveils a sophisticated interplay of technologies governed by SAE standards and OBD-II protocols. Mastery of these systems empowers mechanics to unravel complexities, ensuring optimal performance and emission control for vehicles on the road. 

As technology continues to advance, a deep understanding of automotive acronyms and diagnostic intricacies remains paramount for those entrusted with keeping our vehicles running smoothly. However, it would be feasible even advisable for vehicle owners to get get up to speed with Automotive technology. Technology is here to stay and no matter how hard we try, cannot will it away.

ON-BOARD DIAGNOSTICS 

A few days ago I was driving behind a string of cars through Liesbeek Parkway when I was startled by several drivers repeatedly  hooting at an Audi A4 driving in front of them to get out of the way or change lane. The Audi A4 that was holding up the traffic had a Guateng registration plate and  my first impression was that its occupants got lost at the spaghetti junction fly-over, not knowing which off ramp to take.

However when these impatient hooting drivers finally overtook the Audi A4 and I got to drive behind it;  I then realized that the Audi A4 was in fact in Limp Mode. Its driver was attempting to get to the shoulder of the road from the centre lane and the traffic just wasn't easing up.

In my opinion, these impatient driver just weren't aware that when a vehicle goes into Limp Mode it cannot go any faster than it's already going even though its driver was flooring the accelerator pedal. And I may add that ignorance about Limp Mode is no excuse, because its been around since 1996.

Vehicle Delivery Services Salvaged Limp Mode car

DRIVER COURTESY

Driver courtesy is very important to bolster safe driving conditions for everyone but an education regarding Limp Mode would be considered far more important. When a car suddenly reduces speed after driving at normal speed, it could be one of several reasons; among which could be steering vibration due to a puncture. Or the vehicle ran out of fuel. Or the engine may have switched off due to a dead battery caused by either alternator issues or snapped fan belt. 

Or the engine may be overheating, or the driver heard a disturbing noise coming from the engine. Or it could be an electrical fault like a faulty fuel pump or an ignition system failure like a defective engine or transmission control unit. Or the driver could have fell ill behind the wheel, to mention but a few of the myriad of reasons why a vehicle could stall or it may have entered in Limp Mode. 

AUTOMATIC TRANSMISSIONS

The engines of cars with automatic transmissions can sometimes switch off mid travel for some obscure reason. The only option the driver has, is to pull off the road, bring the car to a halt, place it in park or neutral to restart the engine. I know of someone who shifted his automatic transmission into neutral when the engine cut out mid travel, restarted the car and shifted it back into drive. This caused his car to almost come to a stand-still instantly causing the wheels to screech as the engines inhibited the transmission.  This type of action can and probably will damage the transmission subject to the gearing system inside and should never be done. Unfortunately no On-board diagnostics makes provision to prevent this.

When an engine cuts out at say 100kph both the power steering and vacuum boosted brakes stops working, thereby making steering difficult and the braking inefficient. It is therefore best to pull off onto  the shoulder of the road and check what the problem is an remedy it before continuing on your journey.

ON-BOARD DIAGNOSTICS

On-Board Diagnostics does a pretty decent job of protecting the engine and transmission against damage by limiting  acceleration, keeping the engine revs to a maximum of 2000 (RPM) and speed to about 45kph - aka Limp Mode. When Limp Mode is enabled, it may lock an automatic transmission  in low gear and even disable both heating and air conditioning. Yet keeping the engine running so that it can be driven to a repair shop.

However, as clever as an ECU is,  it doesn't do anything to alert the driver of the car that follows close behind. Considering tail lights, brake light, reverse lights and  indicators represents a language used by vehicle drivers for those  following behind, to indicate their driving intentions. This light language that's been around for the better part of the automotive industry's existence yet it still haven't come-up with an appropriate and safe warning sign/method for Limp Mode. 

LIMP MODE INDICATOR

To remedy this, car manufacturers could include flashing hazard lights or perhaps fit an LED Display with a scrolling message along the the rear window as an alert to tell the driver following behind that the car in front of it has gone into Limp Mode. Alternatively, electronics savvy car owners can fit their own aftermarket hack by identifying the switching output of the appropriate automotive  High Side Switch (HSS) responsible for protection and diagnostics inside the ECU when Limp Mode is enabled.

Automotive industry High-Side Switches /Drivers - Integrated Circuit 

This may not be as easy as it may seem or sounds because of the myriad of automotive chip manufactures, each pushing their our integrated circuits (ICs) running custom/propriety software, among which are Infineon Technologies AG,   Robert Bosch, Qualcomm, Renesas Electronics Corporation (Intersil), NXP Semiconductors,  STMicroelectronics, Texas Instruments, Intel and Microchip Technology Inc, etc.

However, most of these manufacturers produce Power Switches and incorporate Open Load Detection in their design so that they can perform open-circuit diagnosis on loads, such wiper motors, fans, head lamps, fuel pump, mirrors, actuators in general and LED lights while  the load is enabled or disabled. Open load diagnosis is probably the most important function of the software driven High-Side Switch (HSS) and Low-Side Switch when wired in a specific configuration which allows for currents from 5mA to more than 10A to be accurately detected.   

As such able to generate a hardware signal (Limp Mode signal) that can directly control the hardware without the participation of the microprocessor in the ECU. This output can be used to as either a digital High of Low (using CMOS inverter) to drive a LED display that flashes LIMP MODE..... LIMP MODE..... LIMP MODE.....

Overactive Check Engine Light

AUTOMOTIVE RELIABILITY  

All automotive manufacturers have reliability issues with some or certain of their vehicles and Volkswagen is no exception even though it is one of the largest car manufacturer in the world. Globally the masses buy cars in general based on its looks (aesthetics), price, performance and reliability but not necessarily in that order.

In my opinion, reliability play a major role in decision making and should always be considered first. Hence, the question that begs to be asked is, "What's the use of owning a smart looking car with better than average performance that you acquired at a very attractive price but is as unreliable as a career politician". 

Understandably car manufacturers at times produce lemons (The Monday Car) or unknowingly fit a substandard part to some of the vehicles which only becomes apparent when it starts to fail in the field, necessitating a recalls. However, often times these troublesome parts slip through the cracks and fail infrequent enough and disparate enough as not to alert car owners to this pending problem and that is replaceable under recall. 

As a consequence car owners foot the repair bill for something that may never have been necessary to fix or replace if the manufacturer did their due diligence by adequately testing these parts before use. Any and all parts not tress tested or burn-in tested invariably fails and these failing parts then becomes known as Common Problems that plague the car owners.

Case in point, the Volkswagen Jetta 2006 - 2019 appears to have the most issues — aka Common Problems — necessitating seven (7)  major recalls due to some 295 complaints by owners to the National Highway Traffic Safety Administration (NHTSA). When these statistics are compare to the more reliable models, like the Volkswagen Golf GTI and the Tiguan which had absolutely no recalls and a very small number of complaints registered with the NHTSA, one notices the reliability factor.

MISLEADING DATA

This reminds me of how computer hardrives manufactures like Seagate, Western-Digital and Hewlett-Packard etc label hardrives by rating them at 1 Million hours  — MTBF (mean time before failure). One would be misled to believe when manufacturers as a whole guarantees the item/part in question for 1 million hours of operation before failure,. Whereas the said item has not even been in existence or production for this length of time, let alone tested for failure for this duration. One (1) million hours roughly equates to 114 years, so one can see how misleading that rating really is.

WHAT MTBF REALLY MEANS

Having said all that, I feel that MTBF is a really bad measure for determining the probable life span of any item, be it a hardrive, a light bulb, a printer, a TV, a car part or an entire car. However, what MTBF really means, is that if the manufacturer built 1 million units and started running burn-in test on all of them at the same time, one item is expected to fail per hour.  The same hold true for producing 5000 units, implying 1 unit will fail every 5000 hours. This is especially true for electronic components, its failure varying between the stringent implementation or slack specification and tolerances they are manufactured under. 

The German tradition and culture of manufacture in general gives rise to vehicles one can rely on with proven reliability and durability based on robust design, assembly, pride and attention to detail. This is noticeable on cars built and assembled in  Wolfsburg, Lower Saxony, Germany when compared to German designed cars manufactured/assembled elsewhere among which are South Africa, Mexico, Brazil, Asia etc. 

If your Volkwagen's VIN number starts with SN, ST or W you have a car that may outlast you whereas any other "world manufacturer identifier" prefix will virtually guarantee you a life of replacing parts. Purely because they are assembled from parts originating from ancillary OEM parts manufacturers and Chinese auto parts manufacturers instead of genuine VW parts originating from Germany.

Common Problems on Volkswagen vehicles mainly stems from these sub-standard rogue parts and several of them may be responsible for your Overactive Check Engine Light, from your leaking coolant, to excessive oil use and smoking, to engine overheating, to mention but a few.

EXCESSIVE SMOKING

Hard plastic has become the preferred product from which to manufacture modern day car spare parts —  in place of diecast aluminum machined to perfection —  and is used in abundance in most cars to reduce manufacturing costs, the overall weight of the vehicle that consequently improve its millage. 

However these plastic parts do become brittle over time thus prone to failure due to the engine heat. For example a blocked plastic PCV (Positive Crankcase Ventilation) valve — responsible for extracting the blow-by gases from the crankcase —  may be the cause of rough idling, poor acceleration and an increase in oil consumption and as a consequence excessive exhaust smoke. When detected by to O2 sensor will cause the Check Engine Light (CEL) to trigger.

OVER HEATING

Plastic thermostat assemblies commonly leak prematurely when they become contaminated by engine oil from a leaking PCV system. This may lead to that stubborn coolant leak that you cannot find  is more-likely-than-not caused by plastic pipe couplings, plastic hoses connectors, or perhaps the plastic radiator tanks located behind the AC condenser  that developed a minute crack, all able to cause overheating.

VW POLO CANBUS

If you own a Volkswagen Polo, you more likely that not already know that a Controller Area Network (CAN) bus is an automotive wire network loosely referred to as a bus. The word "bus" comes from the electrical power distribution sector where bus-bars were considered a metalic strip made of copper, brass or even aluminium that served as a source of electric power to the load. 

CAN BUS

However CAN Bus is more akin to Ethernet than a bus-bar. Ethernet is a computer networking technology using Unshielded Twisted Pair cable (UTP) either CAT5 or CAT6 which is now commonly used in local area networks capable of sending  IPv4 / IPV6 packet across its networks at speeds ranging from as slow as 10Mb/s to as fast as 1000 Gb/s, hardware dependent of course. 

Twister pair electrical wires with various colour tracers.

Likewise CAN is a network technology commonly used in automotive networks capable of sending CAN-frames across its network at various speeds, again application dependent. It is essentially a  very reliable multi-master arbitration free serial bus, connecting numerous Electronic Control Units (ECUs) aka nodes together.

CAN BUS vs ETHERNET

The big difference between the two, is that Ethernet is an 8-wire bus comprising of 4 unshielded twisted pairs of wire, each with a specific colour coding, whereas CAN has only a single unshielded twisted pair of wires also with a specific colour coding. The CAT5 protocol insists on 2 twists per centimeter and CAT6 with more twists per centimeter whereas the CAN protocol insists on a 1 turn per centimeter. The lay of these wires are very specific and necessary to reduce or cancel interfering signals picked up from the environment by them, which is more commonly referred to as "crosstalk".

CAN BUS HIGH & LOW

Bearing in mind CAN comes in two varieties used for different functions, viz CAN-High (CAN-H) and CAN-Low (CAN-L).  CAN-H is used for the Powertrain, the Convenience and Infotainment buses. 

Whereas CAN-L is used for the rest of the bus wiring.  Both CAN-High and CAN-Low uses different colour wires for different makes of vehicle. For example:-

Manufacturer        CAN High        CAN Low

Mercedes                  Brown/red         Brown

Volvo                        White                Green

Vauxhall                   Green                White 

BMW 1 & 3             Green/orange     Green 

BMW 5 & 6             Black                 Yellow 

Porsche                     Yellow              Black

The big difference between the three buses for VW,SEAT, Skoda and Audi is that:-

1) The Powertrain bus wires interconnected to all the powertrain modules / nodes are coded Orange & Black CAN-H 

2) The Convenience bus wires interconnected to all the convenience modules / nodes are coded Orange & Green CAN-H 

3) The Infotainment bus wires  interconnected  to the infotainment modules / nodes are coded Orange & Violet /Purple CAN-H 

4) CAN-L bus wires to all the interconnected convenience modules / nodes are coded Orange & Brown. (Electronics colour code 31)

REPAIRING WIRES

CAN wires are typically multi-strand 0.35mm to 0.5mm square with 120 ohm termination impedance, capable of transmitting information using two complementary signals which makes them even less prone to crosstalk. But thin wires are prone to break and if and when they do, it is recommended  that when repairing these CAN Bus wires, that both wires must always remain the same length and of equal thickness. 

Implying CAN BUS is extremely unforgiving. So, when wire 1 of the pair is broken, wire 2 should also be cut and the piece of wire added in-between must be exactly the same length; and that the lay length of 1 turn per centimeter must be observed. 

ELECTRICAL INTERFERENCE

Failure to do so, may created a discrepancy in the wire length of the one wire in the twisted pair as well as in their differential voltages, hence result in network errors — ground noise, electrical interference, hum, buzz,  spark plug spikes — cannot and will not be appropriately cancelled. 

Whenever repairs are made to any CAN Bus wiring, it is highly recommended that all CAN Bus wire repairs are covered and highlighted with yellow insulation tape to signify to anyone doing successive work, that a previous repair was carried out.