What it means
The EGR cooler bypass valve on bank 2 is mechanically stuck in the open (bypassing) position - EGR always bypasses the cooler, gas reaches the intake hotter than designed.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 2 EGR cooler bypass directs exhaust gas through the cooler or around it before it returns to the intake. P24A6 means the bank 2 bypass remains open, allowing EGR gas on that bank to stay hotter than intended and potentially increasing NOx emissions or disrupting engine operation.
Common causes
Most likely first.
- Valve stuck open
- Carbon or debris buildup preventing free movement
- Component wear with age - mechanical play
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
How to diagnose it
- Check freeze-frame data and related EGR faults to identify the conditions when the bank 2 bypass was reported open.
- Inspect the bank 2 bypass valve, linkage, and passages for carbon buildup, debris, or mechanical wear.
- Check the bank 2 actuator connector and wiring for corrosion, loose pins, or heat damage.
- Use the scan tool's available actuator test to compare the commanded and observed bank 2 bypass position.
- Test the position feedback circuit, if fitted, using the manufacturer's diagnostic procedure to separate a stuck valve from an electrical fault.
Common fixes
- Clean carbon or debris from the bank 2 bypass mechanism if the service procedure allows it.
- Repair damaged bank 2 actuator wiring or connector terminals.
- Replace the bank 2 bypass valve or actuator if it is mechanically stuck or fails testing.
Can I keep driving?
Avoid heavy acceleration and high engine loads if the engine pings, knocks, or hesitates; the bank 2 bypass fault can increase NOx emissions and worsen drivability. Arrange repair soon if knocking or power loss is significant.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.