Why it matters

In order to communicate with majority of CVT transmissions, CVTz50 requires a good ELM327 interface ("good version 1.4 or 1.5"). CVT diagnostic protocol is more complex than standard engine diagnostics so it requires more functionality from ELM327. This means that many "bad v2.1" interfaces are able to connect to engine howerer are missing features required for establishing a connection with transmission and other control modules. Some "bad" interfaces are still able to provide limited connectivity to CVT in compatibility mode (compatibility mode can be enabled by choosing option "ELM327 v2.15 workaroud" in CVTz50 menu), however advanced functionality will not be working (like clearing "CVTF deterioration date", reading engine brake level, list of previously cleared DTCs, some monitoring parameters).

Where to buy

Fastest and most reliable way of getting proper ELM327v1.5 is buying it at local store. Check it immediately with CVTz50 or CVTz50 DEMO and get moneyback if it unable to connect to transmission. Just one disadvantage - price of the interface will be higher comparing to online stores.

It is also possible to buy a good ELM327 interface via Ebay or Aliexpress, search using keywords ELM327 PIC18F25K80 (PIC18F25K80 is name of the chip inside majority of "good" adapters). The problem is that some sellers are still shipping "fake" interfaces regardless of mentioning the name of good chip in item's description, especially sellers offering lowest price. So before placing an order, it is necessary to check with the seller whether their product really has proper version 1.5 and build on appropriate hardware. Sample query to a seller: Is your ELM327 1.5 built on original Microchip PIC18F25K80? What's the frequency of crystal oscillator there, 4mhz or 16mhz? Does it support commands ATAL and ATPPS?

Difference between good and bad ELM327 interface

Casing of good and bad interfaces is the same (many variants of cases exist however all of them can have fake components inside) so it is needed to look into internals. Many online stores provide pictures of disassembled devices allowing to recognize obvious fakes (though pictures in online shops are not always real).

"Good", "real version 1.5" ELM327 interfaces are built on chip PIC18F25K80 produced by Microchip. As a rule, such interfaces are properly listed as "version 1.5" in online stores. Android application ELM327 Identifier after analysis of such device show that the interface supports all commands of ELM327 protocol till version 1.4.

"Bad" (or fake) interfaces are built on cheap microcontrollers like STM32F042, YM1130, BK3231Q, 25K80 QBD327 and unknown chips hidden under black drop of special varnish. Such interfaces are usually recognized as "Chineese version 2.1", however many unfair sellers are selling these as v1.5. Moreover, when connected to diagnostic software, poor interfaces can report version 1.5 so they are "fake v1.5" (actually they can show any number there). If "bad" interface is not trying to trick the user, than ELM327 Identifier will show that many v1.4 commands are not supported. However if fake ELM327 programmed to cheat diagnostic software, ELM327 Identifier can show same result as for good interface or even better.

Special attention to new kind of fake adapters introduced in 2017 - built on chip QBD327 relabeled as PIC18F25K80. Such relabeled chips have following specialities:

  • Microchip logotype (M) on fake chip is blurred (while original chip has clear and sharp logo)
  • Third line of the label on fake chip has string 14309MP or 1643URE or 1850AAJ; original chip has another strings with encoded production date
  • Fake chip uses crystal oscillator with frequency 16.000MHz (usually located near the chip); original PIC18F25K80 requires crystal oscillator 4.000MHz
  • Fake ELM327 does not support command ATPPS; good ELM327 recognizes command ATPPS and responds to it with list of hex numbers (ATPPS can be sent to the adapter using "Custom commands" in CVTz50 DEMO).

Difference in pictures

Good ELM327 interface: microchip PIC18F25K80 and crystal oscillator 4MHz.
Might be built on one PCB (like on the picture), or on two or three PCBs soldered together

Generally good ELM327 interface (microchip PIC18F25K80 and crystal oscillator 4MHz), however this specific variant with PCB KA2019+switch can be turned on only while engine is running.

Bad ELM327 interface: fake microchip PIC18F25K80 with label 14309MP and crystal oscillator 16MHz

Bad ELM327 interface: microchip STM32 (except Vgate iCar Pro and similar which are priced above average)
Sometimes such interfaces can work with limitations in mode "ELM327 v2.15 compatibility"

Bad ELM327 interface: unknown chip hidden under drop of varnish

Bad ELM327 interface: 2 chips with erased labels. Sometimes 16-pin chip has label "ℼ"

Bad ELM327 interface: unknown chip hidden under drop of varnish

Bad ELM327 interface: unknown chip hidden under drop of varnish is on the back of circuit board

Also following models cannot be easily disassembled but are usually good
Vgate iCar Pro: usually good if original. Price starts from $15.

Konnwei KW903 Bluetooth 4.0: usually good if original, however works only in Bluetooth Low Energy mode which is not compatible with old Android devices. Price starts from $10.

ObdLink LX (or MX, MX+): very good if original. Price from $50.

Viecar 4.0: usually good if original. Price starts from $15.