P2490EGR Cooler Bypass Control Circuit Low (Bank 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2490 means the drive line of the bank 2 cooler bypass actuator sits too close to ground potential, typically a grounded wire between controller and actuator. It mirrors P245C on bank 1. No manufacturer documents P2490 publicly. GM's 2017 diesel tables give an idea of the bank 1 test: the vacuum-switched bypass is failed when the resistance to ground falls below 0.5 Ohm in 24 of 30 samples. Depending on the wiring, a grounded control line can keep the actuator permanently energised or permanently released, so bank 2 either always bypasses or always cools. Look for chafed insulation near the exhaust manifolds and turbocharger, harness clips lost after repairs and water in the connector. An open is P248E, a short toward the supply P2491.
- What you may notice
- Check engine light on
- Bypass on bank 2 stuck in one mode, possibly followed by cooler efficiency codes
- Likely causes
- LikelyDrive wire rubbed through and touching engine ground
- PossibleWater or corrosion in the bank 2 actuator connector
- RareInternal short in the actuator
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.