WJdiag Tutorial


Thank you for using WJdiag diagnostic application.
WJdiag is made for diagnosing issues on Jeep Grand Cherokee 2002-2004 year, WJ/WG models. On 2.7 CRD Jeep model are supported all electronic modules that car have. On gasoline and 3.1 diesel model are supported all electronic modules except Engine and Transmission.
In addition WJdiag can access to many Chrysler Group cars (officially untested) made between 1998 and 2005.

WJdiag is software application and for diagnosing a car, it needs Bluetooth ELM327 diagnostic device. There are many fake ELM327 devices on the market that costs 5…30 EUR, but you should be aware to buy fake ELM327 device, because they may not work correctly. Some of fake ELM327 devices are working, but if you buy fake device, then you never know, will it work or not. We recommend to use ELM327 with GENUINE CHIP made by ELM ELECTRONICS. With genuine ELM devices you can be sure that it is compatible as promised.

There are Basic and Pro versions of WJdiag available. Basic version is free and it have most important functions only: you can READ and CLEAR Engine and Transmission fault codes on 2.7 CRD model. You can also view generic data of other electronic modules like part number, software version, year released etc., but all other data is limited.
With Pro version you will have full opportunities that WJdiag offers – full access to every electronic module, fault codes reading/clearing, Live Data with logging, Input/output values and some coding options.

Before installing WJdiag be sure that you have uninstalled previous versions. Before you buy Pro version, please test your ELM327 device with Basic version. If you can access to engine, transmission and can see generic data of other modules, then your ELM327 is compatible with your Jeep Grand Cherokee. Engine and Transmission of the Jeep 2.7 CRD are using K-Line data bus for diagnostic device, all other electronic modules are using J1850 data bus.

If WJdiag is installed, then you must pair ELM327 diagnostic device through Bluetooth (if it is not already paired). Pairing code for ELM327 devices are usually 1234, you can get correct code from your ELM327 seller. Pairing must be done only once, after successful pairing ELM327 will be remembered by Android.
After opening WJdiag you should connect your ELM327 device. If you have several Bluetooth devices paired with your Android phone/tablet, then list of your paired devices will shown up. Choose correct device and connect it. Engine must be on idle or ignition key must be turned to ON (dashboard lights like battery, oil are lighting and gauges are up).
You will see list of modules that Jeep Grand Cherokees have. This list does not show modules your car exactly have, it is full list that Jeep GC can have. On this list WJdiag is connected with ELM327 device, but not connected with your car. Equipment of your car depends of modules your car have released by factory. Choose module with what you like to work and WJdiag will connect with your car.
If your car have current module, then you will see 4 lines: Fault codes, Sensor Live Data, Input / Output display, Misc / Tests.
By choosing Fault Codes you will see what fault codes or fault explanations are stored in current module and can clear them. Engine and Transmission have Freeze Frame information of every fault code, push to current fault and you will see more specific data about code: times occurred, active/stored etc.

Sensor Live Data will show actual values of current module. There is list of values, on right side select values you like to see and push “Show selected” on top of the screen.
Selected values will shown up on next screen. The more values you choose, the more slowly they are exchanged. Default time between requests is 500ms and it means that if you choose single value, then it will updated after every 500ms and if you choose 2 values, then total refresh time is 1000ms. You can choose this time from application settings, check at end of this tutorial.

Input / Output Display is very similar with Live Data, but it show positions and values of switches, relays etc.

Misc / Tests is for special functions like injector test and coding or speedometer correction coding. On this image is shown injector feedback values. For example injector test: if values are equal, then injectors are fine, if values are unequal, then injectors are not good. Perfect value is if all 5 injectors are on zero.
ABS Pinion Factor coding is made for speedometer correction. For example if you changed tires with larger ones, then speedometer will show incorrect speed. With Pinion Factor coding you can choose how many rotations your wheels are making per one mile.

Open settings page from 3 dot icon on top right side of the screen. There are several settings that you can choose.

Exit. will close the application.

Livedata records. If Live Data logging is enabled, then here you can see log files. Log files are in table format and you can view them if you have excel viewer installed. Excel viewer is not included with WJdiag and you need to install it separately. You can also download log files to your computer and view them with Microsoft Excel, Mozilla OpenOffice or with some other table viewer. Log files location in your Android device is Internal shared storage/WJdiag folder.

Here you can enable and disable Live Data logging.

Next 3 slider buttons are for Metric / Imperial system selecting. Application will convert Live Data values to choosed system.

Livedata and In/Out delay.
Depending on the diagnostic procedure you may need to see Live Data and Input / Output values with different refresh rate. 0ms delay means that application will send next query as soon as answer for previous request is received. With increasing delay you can choose how much time application will wait until new request. Maximum delay can be 10 second. Be mentioned that some ELM327 devices can not handle with high speed and can jam. In such case increase delay until your ELM327 will stable. If you select several values on Live Data display, then every request will have delay.
If you need to monitor some values with minimum delay, then check them one by one.

This link will redirect you to same page you reading at the moment.

This link will redirect you to developer website.

Send Log.
If you have issue with connecting some module or have incorrect results, then you can send log file to us for examining. Log file will be created from traffic with last control unit you used. Log files arrived to us are not monitored automatically, please contact us before sending log file. This option is only for issues with WJdiag like connection problems or values mismatch. We are not offer support for understanding sensors values or car repairing.