P2499 indicates that the powertrain control module has detected a voltage signal from the EGR cooler bypass position sensor on Bank 2 that is below the expected minimum threshold. This typically means the sensor circuit is shorted to ground, open, or the sensor itself has failed internally. The code specifically applies to the sensor that monitors the position of the bypass valve that diverts exhaust gas around the EGR cooler on the second bank of the engine.
The internal sensor has developed a short to ground or open circuit, causing the low voltage signal. This is the most common failure as the sensor operates in a high-temperature environment.
The signal wire between the sensor and PCM has chafed against the frame or engine, creating a path to ground that pulls the circuit voltage low.
A break in the reference voltage, ground, or signal wire prevents proper voltage from reaching the PCM, resulting in a reading below threshold.
Moisture intrusion or oxidation at the sensor electrical connector increases resistance or creates a short, affecting the voltage signal.
Internal failure of the PCM's analog-to-digital converter or reference voltage supply is rare but possible after verifying all wiring and sensors are good.
No. PCM failure is extremely unlikely for this code. The problem is almost always a faulty sensor, wiring short to ground, or connector corrosion. Replace the PCM only after exhaustively testing all wiring and sensors.
Short trips are possible but not recommended. The vehicle may enter limp mode, and emissions will exceed legal limits. Prolonged operation can damage other components.
No. The cooler bypass valve diverts exhaust gas around the EGR cooler when the engine is cold to improve warm-up time, while the main EGR valve controls exhaust flow into the intake manifold.
On V-type engines, Bank 2 refers to the cylinder bank that does not contain cylinder number one. This code indicates the fault is isolated to that specific side of the engine.