Home › Fault codes › U029900
U029900 — Control unit for high-voltage voltage converter (booster) - missing message
Control unit for high-voltage voltage converter (booster) - missing message. The Taycan, 911 (992), Panamera (971), Panamera (972) and Cayenne report this code; below is which control unit sets it on each model and how to read and clear it.
Which models and control units set U029900
How to read and clear U029900
- Plug a standard ENET (Ethernet-to-OBD) cable into your Porsche's OBD port and your Mac or Windows PC.
- Open STEUER14, pick your car and run a fault scan: every control unit is read, and U029900 shows with its status, its full description and the freeze frame when the unit stores one.
- Fix the cause first, then clear the fault memory and scan again to check it stays away. Reading and clearing fault codes is free on every control unit.
More about fault memory in the manual →
Download STEUER14 — free fault readingOther codes of the Engine Control Module 1
| U01BA00 | Solenoid (parking lock) – electrical fault |
| U021200 | Steering wheel electronics control unit – missing messages |
| U023500 | Distance measuring sensor (master - right) - no communication |
| U025900 | Special vehicles control unit - no communication |
| U028A00 | Transmission oil pump – electrical fault |
| U029200 | Front-axle high-voltage power electronics control unit - no communication |
| U029B00 | High-voltage power electronics 3 control unit - missing message |
| U030100 | Motor electronics (DME) software control unit faulty |
| U030400 | Selector support, software incompatible |
| U040200 | Transmission control unit, signal implausible |
| U040400 | Selector support – implausible signal |
| U041100 | High-voltage power electronics control unit – signal implausible |
All 274 codes of this control unit →
Fault names come from the manufacturer's diagnostic data. STEUER14 is independent and not affiliated with Porsche AG. A code tells you what a control unit detected, not always which part failed — check wiring, supply voltage and related codes before replacing parts. STEUER14 shows each fault's full description, status and freeze frame on the car.