Mcp2515 and vag vcds conflict

Using Arduino Programming Questions
1

Hello, i m using mcp2515 with Arduino Uno R3 board. My mcp is connected after volkswagen pq35 gateway drive train can bus and by sketch only have can send (with delay) and can read. I have a problem with vcds car scanner (error when dtcs reading, ecu identification problems and gateway entering timeout, program freezes), in one word - is conflict. That problem can't resolve when i remove the read function, only resolve when i remove send function. Send function delayed by 300-400 ms. I found some info for ack, but i dont understanding what it is help for this.
Send function:

#include <mcp_can.h>
#include <SPI.h>

void sendPID(unsigned char __pid) {
  unsigned char tmp[8] = {0x02, 0x01, __pid, 0, 0, 0, 0, 0};

  byte sndStat = CAN0.sendMsgBuf(0x7E0, 0, 8, tmp);

  if (sndStat == CAN_OK) {
    Serial.print("PID sent: 0x");
    Serial.println(__pid, HEX);
  }
  else {
    Serial.println("Error Sending Message...");
  }
}

Read function:

char* receivePID(unsigned char __pid, int * response) {
  if (!digitalRead(CAN0_INT)) {                      // If CAN0_INT pin is low, read receive buffer
    CAN0.readMsgBuf(&rxId, &len, rxBuf);      // Read data: len = data length, buf = data byte(s)

    sprintf(msgString, "Standard ID: 0x%.3lX, DLC: %1d, Data: ", rxId, len);
    Serial.print(msgString);

    for (byte i = 0; i < len; i++) {
      sprintf(msgString, " 0x%.2X", rxBuf[i]);
      Serial.print(msgString);
    }
    Serial.println("");


    switch (__pid) {
      case PID_ENGINE_RPM:
        if(rxBuf[2] == PID_ENGINE_RPM){
          uint16_t rpm;
          rpm = ((256 * rxBuf[3]) + rxBuf[4]) / 4;
          * response = rpm;
          Serial.print("Engine Speed (rpm): ");
          Serial.println(rpm, DEC);
        }
      break;

    return (char*) "OK";
  }
  return (char*) "ERR:READ";

Can initialization function:

void setupCanService() {
  Serial.begin(115200);

  if (CAN0.begin(MCP_NORMAL, CAN_500KBPS, MCP_8MHZ) == CAN_OK) {
  // can  try MCP_STDEXT
    Serial.println("MCP2515 Initialized Successfully!");
  }
  else {
    Serial.println("Error Initializing MCP2515...");
    while (1);
  }

  //initialise mask and filter to allow only receipt of 0x7xx CAN IDs
  CAN0.init_Mask(0,0,0x07FF0000); // check all 11 address bits for RXB0  
  CAN0.init_Filt(0,0,0x07E80000); // Allow 07E8 through RXB0.
  CAN0.init_Filt(1,0,0x07E90000); // Allow 07E9 through RXB0  

  CAN0.init_Mask(1,0,0x07FF0000); // check all 11 address bits for RXB1  
  CAN0.init_Filt(2,0,0x07EA0000); // Allow 07EA through RXB1  
  CAN0.init_Filt(3,0,0x07EB0000); // Allow 07EB through RXB1  
  CAN0.init_Filt(4,0,0x07EC0000); // Allow 07EC through RXB1  
  CAN0.init_Filt(5,0,0x07ED0000); // Allow 07ED through RXB1
  
  CAN0.setMode(MCP_NORMAL);

  pinMode(CAN0_INT, INPUT);                    // Configuring pin for /INT input

  Serial.println("Sending and Receiving OBD-II_PIDs Example...");
}
2

The issue you're facing with the MCP2515 and Arduino Uno R3, connected to a Volkswagen PQ35 CAN bus, seems to be caused by the 300-400 ms delay in your send function, leading to conflicts with the VCDS scanner. To resolve this, try reducing the delay, ensuring the CAN bus isn't overloaded, and verifying that the MCP2515 is correctly configured. Additionally, check for proper ACK handling and potential address conflicts on the CAN bus.

3

When i make a 1sec send delay, the problem is slightly decreased, but anyway its cause error and timing out, mostly public examples have lower then 300-400 ms delays so it is not fix. CAN overloaded: i have default CAN factory devices with only my mcp2515 non stock device and overload i have only when more then 5000 rpm.
MCP2515 is correctly configured - is physical (like pin connection) or program ? I tried with termination circuit and without (nothing changes).
Address conflicts: i send only 1 message with sendPID func with delay and read it by receivePID once.
About ACK handling, in datasheet i not found way about how i can proper handling it, maybe you know source with more info ?