P2499 stands for a bank 2 bypass position voltage that has fallen to the bottom of its range. No manufacturer documents the bank 2 code publicly. For orientation, GM's 2017 Duramax tables fail the bank 1 sensor (P2494) once its output drops under one percent of the supply and need 200 bad results out of 250 before the Type B fault is stored. A comparable bank 2 check would react to the same electrical causes: the signal wire grounded somewhere along the harness, the sensor supply interrupted or shorted, or a sensor that no longer drives its output. If other 5 V sensors report low values simultaneously, the shared reference circuit is the better starting point. High voltage on bank 2 is P249A, the bank 1 low code P2494.
Medium severity. Can I keep driving?You can normally drive in moderation, but get it repaired soon: if the valve is stuck open, the engine may idle very poorly.
Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.
Symptoms
- Check engine light on
- Bank 2 bypass position reads near zero
Most likely causes
- Bank 2 signal wire touching ground
- 5 V sensor supply interrupted or pulled down
- Sensor output stage failed
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2499 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 4: Emissions
- 99: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2499?
You can normally drive in moderation, but get it repaired soon: if the valve is stuck open, the engine may idle very poorly.
What causes code P2499?
The most common causes are: bank 2 signal wire touching ground; 5 V sensor supply interrupted or pulled down; sensor output stage failed.
Related codes
- P2494EGR Cooler Bypass Position Sensor Circuit Low (Bank 1)
- P2497EGR Cooler Bypass Position Sensor Circuit (Bank 2)
- P2498EGR Cooler Bypass Position Sensor Range/Performance (Bank 2)
- P249AEGR Cooler Bypass Position Sensor Circuit High (Bank 2)
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.