Diagnostic trouble code use cases

PDFRSS

Important

Access to certain AWS IoT FleetWise features is currently gated. For more information, see AWS Region and feature availability in AWS IoT FleetWise.

The following use cases assume the DTC_QUERY function was defined in the demo script.

Periodic fetch

Fetch a DTC collection at configured intervals.

The following example is a campaign with periodic signal fetching of Vehicle.DTC_INFO for all DTCs with a status mask for all ECUs. There is a condition for data collected for Vehicle.DTC_INFO.

{
  "compression": "SNAPPY",
  "spoolingMode": "TO_DISK",
  "signalsToFetch": [
    {
      "fullyQualifiedName": "Vehicle.ECU1.DTC_INFO",
      "signalFetchConfig": {
        "timeBased": {
        // The FleetWise Edge Agent will query the UDS module for all DTCs every five seconds.
          "executionFrequencyMs": 5000
        }
      },
      "actions": [
      // Every five seconds, this action is called and its output is stored in the
      // signal history buffer of Vehicle.DTC_INFO
        "custom_function(\"DTC_QUERY\", -1, 2, -1)"
      ]
    }
  ],
  "signalsToCollect": [
    {
      "name": "Vehicle.ECU1.DTC_INFO"
    }
  ],
  "collectionScheme": {
    "conditionBasedCollectionScheme": {
      "conditionLanguageVersion": 1,
      // Whenever a new DTC is filled into the signal, the data is ingested.
      "expression": "!isNull($variable.`Vehicle.ECU1.DTC_INFO`)",
      "minimumTriggerIntervalMs": 1000,
      // Make sure that data is ingested only when there are new DTCs.
      "triggerMode": "RISING_EDGE"
    }
  },
  "dataDestinationConfigs": [
    {
      "s3Config": 
        {
          "bucketArn": "bucket-arn",
          "dataFormat": "PARQUET",
          "prefix": "campaign-name",
          "storageCompressionFormat": "GZIP"
        }
    }
  ]
}

Condition-driven fetch

Fetch a DTC collection when a condition is met. For example, when the CAN signal is Vehicle.Ignition == 1, fetch and upload the DTC data.

The following example campaign has condition-driven signal fetching of Vehicle.ECU1.DTC_INFO to check whether the DTC ("AAA123") is pending with recordNumber 1 for ECU-1. This campaign has time-based data collection and upload.

{
  "compression": "SNAPPY",
  "spoolingMode": "TO_DISK",
  "signalsToFetch": [
    {
      "fullyQualifiedName": "Vehicle.ECU1.DTC_INFO",
      "signalFetchConfig": {
        "conditionBased": {
        // The action will only run when the ignition is on.
          "conditionExpression": "$variable.`Vehicle.Ignition` == 1",
          "triggerMode": "ALWAYS"
        }
      },
      // The UDS module is only requested for the specific ECU address and the specific DTC Number/Status.
      "actions": ["custom_function(\"DTC_QUERY\", 1, 2, 8, \"0xAAA123\")"]
    }
  ],
  "signalsToCollect": [
    {
      "name": "Vehicle.ECU1.DTC_INFO"
    },
    {
      "name": "Vehicle.Ignition"
    }
  ],
  "collectionScheme": {
    "timeBasedCollectionScheme": {
      "periodMs": 10000
    }
  },
  "dataDestinationConfigs": [
    {
      "s3Config": 
        {
          "bucketArn": "bucket-arn",
          "dataFormat": "PARQUET",
          "prefix": "campaign-name",
          "storageCompressionFormat": "GZIP"
        }
    }
  ]
}

On-demand fetch

Fetch a specific DTC for a fleet.

For an on-demand use case, you can use the same campaign as defined in the periodic fetch. The on-demand effect is achieved by suspending the campaign shortly after the campaign is deployed using the AWS IoT FleetWise console or by running the following CLI command.

• Replace command-name with the command name.

aws iotfleetwise update-campaign \
    --name campaign-name \
    --action APPROVE

Then, suspend the campaign after the DTC data arrives.

aws iotfleetwise update-campaign \
    --name campaign-name \
    --action SUSPEND

You can resume the campaign again for DTC data fetching.

aws iotfleetwise update-campaign \
    --name campaign-name \
    --action RESUME