---
doc-id: SLM-EPB-SVC-001
version: 1.0
status: Released
date: 2026-05-12
---

# Service Manual — Electric Parking Brake (EPB)

| Field         | Value                                  |
|---------------|----------------------------------------|
| Product       | demo-epb EPB ECU                       |
| Version       | 1.0                                    |
| Date          | 2026-05-12                             |
| Audience      | Workshop technicians                   |

---

## 1. Tools

- OBD-II diagnostic tester with UDS support (ISO 14229)
- Torque wrench 60 Nm
- Sliding tool 28×40 mm (for brake-pad replacement)

## 2. UDS diagnostics

### 2.1 Identification

| Parameter         | Value       |
|-------------------|-------------|
| Tester address    | 0x712       |
| ECU response      | 0x71A       |
| CAN baud rate     | 500 kbit/s  |

### 2.2 Service IDs

| SID  | Service                       | Notes                          |
|------|-------------------------------|--------------------------------|
| 0x10 | DiagnosticSessionControl      | 0x03 = Extended Session        |
| 0x11 | ECUReset                      | 0x01 = Hard Reset              |
| 0x14 | ClearDiagnosticInformation   | Clears all DTCs                |
| 0x19 | ReadDTCInformation            | Sub 0x02 = reportDTCByStatusMask |
| 0x22 | ReadDataByIdentifier          | See DID list                   |
| 0x27 | SecurityAccess                | Not implemented in demo        |
| 0x31 | RoutineControl                | 0x0301 = Service mode          |

### 2.3 DIDs (Data Identifiers)

| DID    | Description                          | Type           |
|--------|--------------------------------------|----------------|
| 0xF187 | SW version                            | ASCII 16 byte  |
| 0xF18B | ECU hardware version                  | ASCII 16 byte  |
| 0x0301 | Clamping force left                   | uint16 (N)     |
| 0x0302 | Clamping force right                  | uint16 (N)     |
| 0x0303 | Motor current left                    | uint16 (mA)    |
| 0x0304 | Motor current right                   | uint16 (mA)    |
| 0x0305 | Inclinometer (filtered)               | int16 (m°)     |

## 3. DTC list

| DTC      | Meaning                                          | Action                                |
|----------|---------------------------------------------------|----------------------------------------|
| P0571    | EPB switch plausibility                          | Check switch                            |
| P0572    | EPB switch permanently actuated                  | Switch jammed? Clean                    |
| P0808    | Actuator current left too high (overcurrent)     | Check motor + wiring                    |
| P0809    | Actuator current right too high (overcurrent)    | Check motor + wiring                    |
| P080A    | Clamping force left not reached (apply timeout)  | Check actuator / mechanism              |
| P080B    | Clamping force right not reached                 | Check actuator / mechanism              |
| P080C    | Wheel-speed sensor plausibility                  | Check sensors / wiring                  |
| P080D    | Inclinometer plausibility                        | Check sensor / mounting                 |
| P080E    | Apply controller watchdog trip                   | Software reset; if recurring replace ECU |
| U0123    | CAN bus communication lost                       | Check CAN wiring + BCM status           |

## 4. Service mode (brake-pad replacement)

### 4.1 Activation

Preconditions:
- Ignition on, engine off
- Vehicle on lift or with chocked wheels
- Driver door closed (or door signal bypassed)

Steps:
1. Connect diagnostic tester, Extended Session (0x10 0x03)
2. Send RoutineControl `0x31 01 03 01` — start routine
3. ECU acknowledges, EPB LED starts blinking at 2 Hz
4. Actuators move to maintenance position (fully released)

### 4.2 Deactivation

1. Send RoutineControl `0x31 02 03 01` — stop routine
2. EPB LED stops blinking
3. Apply function available again

### 4.3 Brake-pad replacement procedure

1. Activate service mode (see above)
2. Remove brake calliper
3. Replace pads, grease guides
4. Tighten calliper to 60 Nm
5. Deactivate service mode
6. Perform three apply/release cycles (bedding-in)
7. Clear DTC memory (service 0x14)

## 5. Sensor check

### 5.1 Wheel-speed sensors

- Resistance: 800-1500 Ω at 20 °C
- Voltage at 50 km/h: 2-5 V peak-to-peak (Hall)

### 5.2 Inclinometer

- SPI bus 1 MHz
- Expected value on level road: 0 ± 0.5°
- Drift check: ECU + tester, monitor > 5 min

## 6. Actuator check

| Parameter             | Target value           |
|-----------------------|------------------------|
| Resistance per motor  | 0.8 – 1.2 Ω           |
| Nominal current       | 3 – 5 A               |
| Peak current (apply)  | 15 – 25 A             |
| Cutoff threshold      | 8 A for 100 ms        |

## 7. Software update

1. UDS Extended Session (0x10 0x03)
2. Programming Session (0x10 0x02)
3. Flashloader sequence per OEM specification
4. Verify new SW version via DID 0xF187

## 8. Revision history

| Version | Date        | Change              | Author     |
|---------|-------------|---------------------|------------|
| 1.0     | 2026-05-12  | First release       | S. Lohmaier|