P2AA6 code meaning
EGR Cooler Bypass Control Circuit Driver Current/Temperature Too High Bank 2
Powertrain system Generic code P2Axx codes Check engine light
What P2AA6 means
P2AA6 is the bank 2 version of the bypass driver protection code. It only exists on engines with a separate EGR cooler and bypass actuator for the second cylinder bank, typically V engines whose banks each have their own exhaust manifold feeding EGR. The output stage for that actuator reports excessive current or junction heat and shuts itself off, which leaves the flap where it was. No manufacturer documents P2AA6 publicly. GM's diesel tables, which define the bank 1 code P2AA5 with a 170 °C driver limit and a Type B rating, show no bank 2 counterpart, as those engines use a single bypass. Causes match bank 1: a binding flap, a damaged motor or a partial short. Circuit faults on bank 2 are P248E, P2490 and P2491; a stuck flap is P24A6.
P2AA6 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2AA6
- Malfunction indicator lamp on
- Bank 2 bypass flap stays in its last position
- Possible NOx or EGR temperature codes for bank 2
Common causes of P2AA6
- Most likelyBank 2 bypass flap binding on soot or corrosion
- PossibleInternal fault in the bank 2 actuator motor
- PossiblePartial short in the bank 2 actuator wiring
- Less likelyFaulty driver stage in the engine control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR cooler bypass valve b2ECM
What each part of P2AA6 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| A | Area: hybrid propulsion. |
| A6 | The exact fault in that area. |
What to do next
- Note P2AA6 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2AA6
What does P2AA6 mean?
P2AA6 means "EGR Cooler Bypass Control Circuit Driver Current/Temperature Too High Bank 2". P2AA6 is the bank 2 version of the bypass driver protection code. It is a generic code, so it means the same on every make.
Is it safe to drive with P2AA6?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2AA6 fail an emissions test?
Yes, it can. P2AA6 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2AA6 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P2AA6 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.