P2499 EGR Cooler Bypass Position Sensor Circuit Low (Bank 2)

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.

Likely causes

Symptoms

• Check engine light on
• Bank 2 bypass position reads near zero

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, gsi.ext.gm.com.