Hands-On: DTC Configuration & Testing

#!/usr/bin/env python3
# DTC lifecycle: inject fault, confirm, clear, verify each status bit

import udsoncan, time
from udsoncan.client import Client

def inject_fault(client, enable: bool):
    # Write fault injection DID: 0xFFF1 = fault enable flag
    client.write_data_by_identifier(0xFFF1, bytes([0x01 if enable else 0x00]))

def read_dtc_status(client, dtc_id: int) -> int:
    resp = client.get_dtc_by_status_mask(0xFF)
    for dtc in resp.service_data.dtcs:
        if dtc.id == dtc_id:
            return dtc.status.byte
    return 0  # not found = status 0

def run_lifecycle_test(client):
    DTC_OIL = 0x0520   # P0520

    # Phase 1: inject fault; verify pending after 1 cycle
    inject_fault(client, True)
    time.sleep(0.5)  # wait for one DEM task cycle
    status = read_dtc_status(client, DTC_OIL)
    print(f"After 1 fail:  status=0b{status:08b}  pending={bool(status&0x04)}")
    assert status & 0x04, "FAIL: bit 2 (pending) should be set"

    # Phase 2: inject again; verify confirmed
    inject_fault(client, True)
    time.sleep(0.5)
    status = read_dtc_status(client, DTC_OIL)
    print(f"After 2 fails: status=0b{status:08b}  confirmed={bool(status&0x08)}")
    assert status & 0x08, "FAIL: bit 3 (confirmed) should be set"

    # Phase 3: clear; verify status reset
    client.clear_dtc(0xFFFFFF)
    status = read_dtc_status(client, DTC_OIL)
    print(f"After clear:   status=0b{status:08b}  expected=0b00010000 (notCompleted)")

    print("Lifecycle test PASSED")

#!/usr/bin/env python3
# Verify freeze frame content matches vehicle state at DTC confirmation

import udsoncan, struct, time
from udsoncan.client import Client

def run_freeze_frame_test(client):
    DTC_OIL = 0x0520

    # Set known vehicle state before triggering fault
    client.write_data_by_identifier(0xFFF0, bytes([0x00, 0x50]))  # speed = 80 km/h
    client.write_data_by_identifier(0xFFF2, bytes([0x5A]))         # coolant = 90°C

    # Trigger DTC confirmation (2 failed cycles)
    for _ in range(2):
        client.write_data_by_identifier(0xFFF1, bytes([0x01]))  # inject fault
        time.sleep(0.1)

    # Read freeze frame
    resp = client.get_dtc_snapshot_record_by_dtc_number(DTC_OIL, 0xFF)
    if not resp.positive:
        print("FAIL: No snapshot stored"); return

    for record in resp.service_data.dtcs[0].snapshots:
        data = record.raw_data
        speed_kmh = struct.unpack(">H", data[0:2])[0] if len(data) >= 2 else None
        print(f"Snapshot DID 0xF40D (speed): {speed_kmh} km/h (expected: 80)")
        assert speed_kmh == 80, f"FAIL: speed in snapshot={speed_kmh}"

    print("Freeze frame content PASSED")

#!/usr/bin/env python3
# Simulate DTC aging: trigger drive cycles; verify DTC disappears after 40 healing cycles

import udsoncan, time
from udsoncan.client import Client

def simulate_drive_cycle(client):
    # Signal a completed drive cycle to DEM via diagnostic DID
    # (In real ECU: DEM_OPERATION_CYCLE_STARTED + DEM_OPERATION_CYCLE_STOPPED)
    client.write_data_by_identifier(0xFFF3, bytes([0x01]))  # drive cycle trigger
    time.sleep(0.05)

def run_aging_test(client):
    DTC_OIL = 0x0520

    # 1. Confirm the DTC
    for _ in range(2):
        client.write_data_by_identifier(0xFFF1, bytes([0x01]))
        time.sleep(0.1)
    assert read_dtc_status(client, DTC_OIL) & 0x08, "DTC not confirmed"

    # 2. Heal the fault
    client.write_data_by_identifier(0xFFF1, bytes([0x00]))
    time.sleep(0.1)

    # 3. Simulate 39 drive cycles — DTC should still be confirmed
    for i in range(39):
        simulate_drive_cycle(client)
    status = read_dtc_status(client, DTC_OIL)
    print(f"After 39 cycles: confirmed={bool(status&0x08)}  (expected: True)")

    # 4. One more drive cycle (cycle 40) — DTC should be aged out
    simulate_drive_cycle(client)
    status = read_dtc_status(client, DTC_OIL)
    print(f"After 40 cycles: confirmed={bool(status&0x08)}  (expected: False)")
    assert not (status & 0x08), "FAIL: DTC should have aged out after 40 cycles"

    print("Aging test PASSED")