VW MEB DCDC
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General
Information on the VW MEB DC-DC converter.
Damien has done a lot of work on this, visit his github:
https://github.com/damienmaguire/VW-MEB-DCDC-Hacking
- Bosch Gen4H13
- PN 1EA907190G
- Requires CAN-FD. The bus runs at 500 kbit/s nominal / 2 Mbit/s data. Standard CAN will not work.
Wiring and Plugs
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CAN Messages
Transmitted (TX)
| ID | Name | Interval | Description |
|---|---|---|---|
| 0x20F | NVEM_10 | 50 ms | 12V setpoint. Byte 7 = voltage raw: (V - 10.6) / 0.025
|
| 0x503 | HVK_01 | 100 ms | Mode request. See below. |
| 0x271 | HVLM_13 | 100 ms | Charging management frame |
| 0x5BB | - | 500 ms | Keep-alive (zeros) |
| 0xCF | BMS_20 | 100 ms | Pack voltage (precharge only) |
Received (RX)
| ID | Name | Description |
|---|---|---|
| 0x0F7 | DCDC_04 | Status. DC_IstModus_02 at bit 41.
|
| 0x2AE | DCDC_01 | HV voltage. DC_IstSpannung_HV at bits 12-23, scale 0.25V.
|
| 0x3F4 | DCDC_02 | Status |
| 0x5CD | DCDC_03 | Status |
HVK_01 (0x503) Mode Bits
Byte 3 contains the mode request:
- Bits 0-2: BMS mode
- Bits 3-5: DC-DC mode (
HVK_DCDC_Sollmodus)
DC-DC modes:
- 0 = Standby
- 1 = Precharge (
HV_On_Vorladen) - 2 = Buck (
Tiefsetzen)
Byte 1 high nibble:
- 0x6 = normal
- 0xE = precharge active
DTC Types
The DC-DC stores two categories of DTCs:
Standard DTCs
Communication and operational faults that clear when the condition resolves or with a standard DTC clear (service 14). Examples:
- Lost communication with BMS
- Bus performance faults
- Voltage sensor range/performance
Persistent DTCs
Protected faults that survive power cycles and standard DTC clears. These require specific vehicle conditions to clear:
| DTC | Code | Description |
|---|---|---|
| Crash Lock | - | Latched after crash detection. Prevents operation. |
| P1BC300 | 0x54 0xED | HV interruption detected. Prevents operation. |
| P0E5600 | 0x0D 0x65 | Input voltage too low |
Clearing persistent DTCs:
The unit clears these when it sees a valid vehicle environment. No diagnostic session or clear command is required — just the right frames on the bus for ~15 seconds.
Minimum frame set (from verified log):
| ID | Name | Interval | Purpose |
|---|---|---|---|
| 0x3C0 | Klemmen_Status_01 | 100ms | Ignition (Kl15) on |
| 0x503 | HVK_01 | 100ms | Mode request |
| 0x5A2 | - | 500ms | Vehicle status |
| 0x6B2 | Diagnose_01 | 1000ms | Unlearn counter, odometer |
| 0x6B7 | - | 1000ms | - |
| 0x700 | Tester Present | 1000ms | Keep diagnostic session alive |