The output driver for the exhaust pressure control valve A reports current or junction temperature above its protection threshold. Stalled actuator or short-circuit fault.
Medium severity. Can I keep driving?Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.
Most likely causes
- Valve actuator mechanically jammed
- Control wire shorted to ground
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It can trigger limp mode.
- It affects emissions.
What each character of P2B99 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- B: Subsystem depends on the code range
- 99: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2B99?
Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.
What causes code P2B99?
The most common causes are: valve actuator mechanically jammed; control wire shorted to ground.
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.