> For the complete documentation index, see [llms.txt](https://help.pd1.sg/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.pd1.sg/pd-1/scan-and-fault-codes.md).

# Scan & Fault Codes

Scan your vehicle and understand fault codes.

Learn how to scan your vehicle and review fault codes.

## Before you start

* PD-1 is plugged into the OBD‑II port
* Ignition is **ON** (engine may be running)
* PD-1 is connected in the PD-1 app
* A vehicle profile is selected
* Bluetooth and Location are enabled on your phone
* Internet is available for the first data package download

{% hint style="info" %}
If you see **No PD-1 connected!**, tap **Connect PD-1** first. If PD-1 is currently on PD-Display, switch it to the phone when prompted.
{% endhint %}

## Run a scan

{% stepper %}
{% step %}

### Open Diagnostic

In the PD-1 app, open the **Diagnostic** tab.
{% endstep %}

{% step %}

### Start a scan

Under **Check Car for Fault Codes**, tap **Start** for a **Quick Scan** (about 1 minute).

For more control, open the Scan hub and choose:

* **Quick Scan** — faster check
* **Full Scan** — all available control units
* **Custom Scan** — pick units, then tap **Scan**
  {% endstep %}

{% step %}

### Verify the vehicle (if asked)

When **Verify Vehicle Match** appears, confirm **Brand**, **Model**, and **Year**, then tap **Yes**.

If the VIN does not match your current vehicle, you can switch, edit, or add a vehicle.
{% endstep %}

{% step %}

### Download the data package (first time)

On the first scan, tap **Download Now** on **Download Data Package** (about 2–3 minutes).

Keep the app open until you see **Download Complete**, then tap **Start Scan**.

{% hint style="info" %}
Later scans may ask you to **Upgrade Data Package** if a newer vehicle database is available.
{% endhint %}
{% endstep %}

{% step %}

### Wait for the scan to finish

Stay in the app until scanning completes. You can **Pause**, **Resume**, or **Stop** if needed.

When it finishes, you will see **Fault Codes Detected** or **No Fault Codes Detected**.
{% endstep %}
{% endstepper %}

## Read the results

Scanned items are grouped by system (for example Engine, Transmission, Brakes). Each unit shows **Normal**, a DTC count, or **Not Detected**.

{% stepper %}
{% step %}

### Open a control unit

Tap a unit that has codes to open the ECU detail list.
{% endstep %}

{% step %}

### Open Fault Details

Tap a code to see:

* Fault name and **Code**
* **Description**
* **Possible Symptoms**
* **Repair Importance Level** — Low / Medium / High
* **Estimated Cost** (Part, Labour, Total), when available
  {% endstep %}

{% step %}

### Use extra tools (optional)

On Fault Details you can:

* **Ask AI** — explain possible causes and next steps
* **Freeze Frame** — snapshot of vehicle data when the code was stored (only if the vehicle has freeze frame data)
* **Post to Forum** — share the code with the community
  {% endstep %}

{% step %}

### Save a report

Tap **View Report** (or open the **Report** tab) to keep a record of this scan.
{% endstep %}
{% endstepper %}

{% hint style="info" %}
Past scans are under the **History** tab in the Scan hub — that is scan session history, not a Current / Pending code filter.
{% endhint %}

## Clear fault codes

If the scan found codes, tap **Clear DTC**, then **Confirm**.

On success you will see **Clear DTC successful** and how many codes were cleared.

{% hint style="warning" %}
Clearing codes does not fix the underlying issue. If the fault is still present, the code (and warning light) can return. On some BMW vehicles, restart the car after clearing.
{% endhint %}

Then tap **Rescan** to confirm whether codes come back.

## If something blocks the scan

| Message / situation        | What to try                                                   |
| -------------------------- | ------------------------------------------------------------- |
| **Add a New Vehicle**      | Add a vehicle, then connect PD-1                              |
| **No PD-1 connected!**     | Tap **Connect PD-1**; check the green blinking light          |
| **Download Failed!**       | Check internet, then **Retry Download**                       |
| **Vehicle Mismatch**       | Switch, edit, or add the vehicle that matches the scanned VIN |
| Scan stuck / cancelled     | Stay in the app; restart with ignition ON and PD-1 connected  |
| **Not Detected** on a unit | That module may not be available on this vehicle or this scan |

## Next steps

1. Review [Vehicle Health](/pd-1/vehicle-health.md) for longer-term insights.
2. Use [Live Data](/pd-1/live-data.md) to watch related sensors in real time.
3. If a scan will not start, see [PD-1 Troubleshooting](/pd-1/pd-1-troubleshooting.md).


---

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