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The version is OK, thats the internal version Git creates when I build the
firmware.
Make sure the car is running when requesting the trouble code.
…On Thu, Apr 30, 2026 at 9:40 PM jaymik ***@***.***> wrote:
Making progress now that WiCAN messages show up in MQTT Explorer!
However, I'm still not getting DTC codes. I ran the query on the WiCAN
directly and got a "no response" message, making me think I still don't
have WiCAN configured correctly.
7F1C7D61-594D-4472-AD09-97D3FC00B7EB.jpeg (view on web)
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<https://github.com/user-attachments/assets/318ae804-6a3c-4ca6-b41a-0c0ea9152097>
Additionally, I know for sure I loaded the .bin for v14, but the status
page still shows v12. Is that a clue or a red herring?
81F75E8B-B768-4E43-ACF3-E12D5177E051.jpeg (view on web)
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The vehicle is a Honda using Protocol 7 (ISO 15765-4 CAN, 29-bit ID, 500 kbaud). Reading DTCs on a 29-bit CAN bus usually requires establishing explicit Flow Control and setting precise Physical Headers for multi-frame responses. Car Scanner does this automatically in the background, but the WiCAN Pro needs these parameters manually defined via AT commands to handle the long diagnostic responses. Here are the exact AT command sequences extracted from the log to configure the WiCAN Pro for DTCs. The Base Initialization Sequence Routine 1: Generic OBD2 Emissions DTCs (Service $03) Send these commands: Note: If the vehicle has standard emissions codes, they will return here starting with 18DAF... followed by 43 and the hex codes. If clear, you will just get 43 00. |
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So, The WiCAN sent 03, and four different computers inside the Honda replied. that's why you got multiple responses. Here's a brake down of the info:
You used ATE0;ATH1;ATAL;ATSP7;.
The WiCAN sent 03, and four different computers inside the Honda replied. Let's translate them:
In standard OBD2 protocol, the hex 0420 translates directly to the alphanumeric code.
The Honda is currently throwing a P0420 code (Catalyst System Efficiency Below Threshold - Bank 1). This is an incredibly common code for older Hondas, usually pointing to a tired catalytic converter or a lazy downstream O2 sensor.
Look at the green parsed text at the bottom: - dtc_raw: 43010420
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Submitted a fix for the DTCs not sending out via MQTT. Beta 16 |
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I wanted to note for posterity some changes I had to make to get my setup to work: Phase 2: The Home Assistant Sensor (configuration.yaml) - active_dtcs_raw
+ dtc_rawPhase 3: The Dictionary Macro - /* ... paste your entire factory list here ... */ |
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Below are the instructions to Query DTCs for your vehicle and generate in Home Assistant the Code and text strings. This is very involved but for me very worth it!!
Note ***, This requires the Beta 9 SW from https://github.com/wambs/wican-fw/releases
To get you DTCs code to String, will require you to search for your car manufacture.
Phase 1: Creating the DTC Query in the WiCAN Web UI
We will configure the WiCAN to broadcast a Mode 03 command, process the hex data through your custom C-firmware, and publish it directly to a dedicated MQTT topic.
Open your WiCAN Pro Web UI in your browser.
Navigate to the Custom PIDs (or Vehicle) section.
Click Add New PID and configure the fields exactly like this:
Once saved, your WiCAN will begin broadcasting to your new dedicated topic. The payload arriving at homeassistant/wican/your_car/dtcs will look like this: {"dtc_raw": "4303C60FC68B2104"}. If you have no active DTCs will look like this: {"dtc_raw": "4300"}.
Phase 2: The Home Assistant Sensor (configuration.yaml)
Add the following under your mqtt: -> sensor: block. Notice that both topics now point strictly to the dtcs path.
Phase 3: The Dictionary Macro
For the above YAML to work, Home Assistant needs the dictionary file to look up the English definitions.
Crucial Step: Restart Home Assistant completely so it registers the new .jinja file and applies the configuration.yaml changes.
Phase 4: The Dashboard UI
Finally, we build the interactive dashboard element. This uses a custom button that blinks amber when codes exist, clears the codes on a long press, and drops down a formatted text box of your faults on a single tap.
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