ONE ERROR

[toprakb66]

"Hello my friend, I hope you're doing well. I made this project and connected everything according to the schematic you showed using Arduino Nano. I also added the code and connected it to the car, but I can't establish communication with the OBD no matter what I do. There's no communication, and I'm about to lose my mind. Can you give me some ideas?"

[toprakb66]

"Initialising... The serial monitor keeps saying this."

[muki01]

Hello.

1. Which scheme are you using?

2. Which pins are you using with Arduino nano?

3. Is there pin 7 on your car's OBD2 connector?

[toprakb66]

"I am using pins 7 and 8, yes, my car's OBD has a pin 7. I am using the Basic Code, the one with the .ino file."

[toprakb66]

"I was able to get a response when I connected the OBD2 device using the 'ISO9141' and 'ISO14230_Slow' protocols. There is no issue with the car."

[toprakb66]

"I'm stuck in this loop with the messages: 'Initialising... Received Data: 55 8 8 Received Data: F7'. What could be causing this?"

[toprakb66]

"I’m receiving the following responses when using the protocol String protocol = "ISO14230_Fast";:

Live Data: Writing Data Received Data: C2 33 F1 1 D F4 Speed: 0 Writing Data Received Data: C2 33 F1 1 C F3 Engine RPM: 0 Writing Data Received Data: C2 33 F1 1 5 EC Coolant Temp: 0 Writing Data"

[toprakb66]

Received Data: C2 33 F1 1 5 EC 83 F1 18 7F 1 12 1E
Coolant Temp: 0
Writing Data
Received Data: C2 33 F1 1 F F6 83 F1 18 7F 1 12 1E
Intake Air Temp: 0
Writing Data
Received Data: C2 33 F1 1 11 F8 83 F1 18 7F 1 12 1E
Throttle: 0
Writing Data
Received Data: C2 33 F1 1 E F5 83 F1 18 7F 1 12 1E
Timing Advance: 0

[muki01]

Received Data: C2 33 F1 1 5 EC 83 F1 18 7F 1 12 1E Coolant Temp: 0 Writing Data Received Data: C2 33 F1 1 F F6 83 F1 18 7F 1 12 1E Intake Air Temp: 0 Writing Data Received Data: C2 33 F1 1 11 F8 83 F1 18 7F 1 12 1E Throttle: 0 Writing Data Received Data: C2 33 F1 1 E F5 83 F1 18 7F 1 12 1E Timing Advance: 0

If you get data like "C2 33 F1 1 5 EC 83 F1 18 7F 1 12 1E", it means your Arduino is connected to car ECU. This request code "C2 33 F1 1 5 EC" is written by Arduino and this "83 F1 18 7F 1 12 1E" is the response of the car, but this response means an error. Can you message me the console output in ISO9141 protocol.

[toprakb66]

"Of course, buddy. The result with the 9141 protocol is as follows:

Received Data: F7
Initialising...
Received Data: 55 8 8
Received Data: F7
Initialising...
Received Data: 55 8 8
Received Data: F7
Initialising...
Received Data: 55 8 8
Received Data: F7
Initialising...
Received Data: 55 8 8
Received Data: F7
Initialising..."

[muki01]

Ops my bad your protocol is ISO14230_Slow but i dont know why your car response like this. What you receive here

Serial.println("Suported LiveData: ");
  for (int i = 0; i < 32; i++) {
    Serial.print(supportedLiveData[i]);
    Serial.print(", ");
  }
  Serial.println();

after you Arduino is connected to your car?

[toprakb66]

"Yes, the Arduino is currently connected to my car. Could there be an issue in the code?"

[muki01]

Wait, I will modify the code and you will try with the modified code.

[toprakb66]

"My friend, I’m waiting excitedly for your response. I’m so grateful for your help, I’ve been working on this for four days now."

[muki01]

I think I had a bug in the Basic code. Try this code and send me serial output.
Basic_Code.zip

[muki01]

Keep the protocol in automatic mode, don't change it and send me serial output.

[toprakb66]

I'm encountering the following error in my new code: C:\Users\elato\AppData\Local\Temp\5631c5f7-2852-428a-a332-5a3985e80d62_Basic_Code.zip.d62\Basic_Code\Basic_Code.ino: In function 'void loop()':
C:\Users\elato\AppData\Local\Temp\5631c5f7-2852-428a-a332-5a3985e80d62_Basic_Code.zip.d62\Basic_Code\Basic_Code.ino:38:25: error: 'init_OBD2' was not declared in this scope
bool init_success = init_OBD2();
^~~~~~~~~
C:\Users\elato\AppData\Local\Temp\5631c5f7-2852-428a-a332-5a3985e80d62_Basic_Code.zip.d62\Basic_Code\Basic_Code.ino:38:25: note: suggested alternative: 'init_OBD'
bool init_success = init_OBD2();
^~~~~~~~~
init_OBD
C:\Users\elato\AppData\Local\Temp\5631c5f7-2852-428a-a332-5a3985e80d62_Basic_Code.zip.d62\Basic_Code\Basic_Code.ino:46:5: error: 'read_K' was not declared in this scope
read_K();
^~~~~~
C:\Users\elato\AppData\Local\Temp\5631c5f7-2852-428a-a332-5a3985e80d62_Basic_Code.zip.d62\Basic_Code\Basic_Code.ino:46:5: note: suggested alternative: 'read_ID'
read_K();
^~~~~~
read_ID

exit status 1

Compilation error: 'init_OBD2' was not declared in this scope
It seems like a library error, and I'm currently working on fixing it.

[muki01]

Unzip all the files into one folder and it will work.

[toprakb66]

Initialising...
Received Data: 55 8 8
Your Protocol is ISO9141
Received Data: F7
Initialising...
Received Data: 55 8 8
Your Protocol is ISO9141
Received Data: F7
Initialising...
Received Data: 55 8 8
Your Protocol is ISO9141
Received Data: F7
Initialising...
Received Data: 55 8 8
Your Protocol is ISO9141
Received Data: F7
Initialising...

[toprakb66]

"I can only see these kinds of values in Fast mode: Speed: 0
Writing Data
Received Data: C2 33 F1 1 C F3 83 F1 18 7F 1 12 1E
Engine RPM: 0
Writing Data
Received Data: C2 33 F1 1 5 EC 83 F1 18 7F 1 12 1E
Coolant Temp: 0
Live Data:
Writing Data
Received Data: C2 33 F1 1 D F4 83 F1 18 7F 1 12 1E
Speed: 0
Writing Data
Received Data: C2 33 F1 1 C F3 83 F1 18 7F 1 12 1E
Engine RPM: 0
Writing Data
Received Data: C2 33 F1 1 5 EC 83 F1 18 7F 1 12 1E
Coolant Temp: 0
Live Data:"

(FAST PROTOCOL)

[muki01]

I don't know why this happens to you. I have tested all the protocols and they worked for me. I guess it's due to the timing because all ECUs send the response at different times. I'll tell you a few things to change and try.

1. Increase the time in line 99 "REQUEST_DELAY = 50;" from 50 to 100 and test.
2. In line 103 "if (resultBuffer[1])" change resultBuffer[1] to resultBuffer[0]

Try these steps separately. Keep the protocol in automatic mode.

[muki01]

I dont know how you can receive data like this C2 33 F1 1 C F3 83 F1 18 7F 1 12 1E . This means you are initialised in ISO14230_Fast but your protocol is ISO9141. This is very strange.

[toprakb66]

"Buddy, I translated it and here’s what happened:

Live Data:
Writing Data
Received Data: 68 6A F1 1 D D1
Speed: 0
Writing Data
Initialising...
Received Data: 55 8 8
Your Protocol is ISO9141
Received Data: F7
Init Success !!
Live Data:
Writing Data
Received Data: 68 6A F1 1 D D1
Speed: 0
Writing Data
Received Data: 68 6A F1 1 C D0
Engine RPM: 0"

[toprakb66]

After the last adjustment, the results turned out like this.

[toprakb66]

Although a value has been read from the OBD, it's indicating 161 degrees Celsius (based on the conversion from hex C9), which seems to be incorrect. This suggests there's an issue either with how the data is being interpreted or a sensor error. Received Data: 68 6A F1 1 5 C9
Coolant Temp: 0

[toprakb66]

That means it worked!

[muki01]

No, this 68 6A F1 1 5 C9 is the request code that the arduino sends, not the response from the ECU.

[muki01]

Ops my bad not in lines 66 and 70 in lines 99 and 103. if you changed in this lines and the response is this, change the time to 40 in line 99. and in line 103 the code should look like this "if (resultBuffer[1]) {"

[toprakb66]

Unfortunately, the result is the same. Are there any other alternatives?

[muki01]

Which pins do you have in your car's OBD2 port
for example in the OBD2 port of my car I have pins 2,4,5,7,8,16

[muki01]

Do you still need help?

[toprakb66]

Should I provide VCC to the L9637 from the ESP or 12V?

[muki01]

From ESP

[toprakb66]

Is there a 3V output on the ESP that can trigger?

[toprakb66]

The ESP is providing 3V; will it be able to trigger the L9637?

[muki01]

I didn't quite understand what you meant.

[toprakb66]

Bro, the ESP8266 is providing a 3V output. Is this 3V enough for the L9637?

[muki01]

Yes

[toprakb66]

The result is still negative; there is no response from the vehicle again. I can't proceed without the serial monitor, so it seems I will have to wait for the ESP32. My only concern is that the L9637's datasheet states an operating voltage of 5V, but you operated it at 3V.

[toprakb66]

I made a protocol change, but the result is still the same. While changing the protocol, the Wi-Fi connection keeps disconnecting and reconnecting. Is this normal?

[muki01]

The result is still negative; there is no response from the vehicle again. I can't proceed without the serial monitor, so it seems I will have to wait for the ESP32. My only concern is that the L9637's datasheet states an operating voltage of 5V, but you operated it at 3V.

Where did you read that it says 5 volts see the picture.

[muki01]

I made a protocol change, but the result is still the same. While changing the protocol, the Wi-Fi connection keeps disconnecting and reconnecting. Is this normal?

Yes it is normal.

[toprakb66]

It was written on the website where I bought the chip; I didn't check the datasheet. My friend, what’s the plan now? What can we do? Should I wait for the ESP32?

[muki01]

In my opinion, with ESP32 the result will be the same as with Arduino Nano. It does not depend on the microcontroller and with the simplest microcontroller that has a UART it should work. If I find something, I will write to you.

[muki01]

Are you changing anything in the code at all?

[toprakb66]

no

[muki01]

Can you try this code with Arduino Nano. This code is for ISO9141 only and my first code that I tested in an ISO9141 car and it worked.

OBD2_ISO9141.zip

[muki01]

This code doesn't have many features and is very short.

[toprakb66]

It got stuck at initializing.

[toprakb66]

If it’s working on your Uno like this, the only explanation is that there is an issue with my circuit.

[toprakb66]

There was another friend having the same issue, and he recently started a new thread. I’m eagerly waiting for his results.

[muki01]

Can you show me the schematics you made in detail.

[toprakb66]

Received Data: C1 33 F1 81 66
Initialising...
Writing Data
Received Data: C1 33 F1 81 66
Initialising...
Writing Data
Received Data: C1 33 F1 81 66
Initialising... The serial monitor I got using basic code on Arduino Uno.

[toprakb66]

[toprakb66]

I made it on a breadboard for better understanding. I also have the same version on a soldered PCB, and I'm using that one.

[toprakb66]

![son](https://github.com/user-attachments/assets/beb49e56-c526-4c1a-aa8d-42d7b5941684)

[toprakb66]

[muki01]

The schematic looks good. Just change the protocol to İSO9141 because in this picture it only uses İSO14230 Fast and the car doesn't respond anything and with İSO9141 the car responds well and your car's protocol is İSO9141

[toprakb66]

Initialising ISO9141...
First 3 Bytes: 55 8 8
Other Bytes: F7
Init Success !!

[toprakb66]

Bro, I got this response in the short and simple code you gave me."