P2AA6: EGR Cooler Bypass Control Circuit Driver Current/Temperature Too High Bank 2

What it means

The output driver for the EGR cooler bypass actuator on bank 2 reports current or junction temperature above its protection threshold. Stalled actuator or short to ground.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

The EGR cooler bypass actuator on bank 2 controls whether exhaust passes through the cooler or bypasses it. P2AA6 sets when the output driver for that bank's actuator detects excessive current or driver temperature, often from a jammed bypass or a control wire shorted to ground.

Common causes

Most likely first.

1. Bypass actuator mechanically jammed
2. Control wire shorted to ground

Symptoms

• Check engine light on
• Possible reduced power

How to diagnose it

1. Record freeze-frame data and check bank 2 bypass command and related EGR codes to identify when the driver fault occurs.
2. Inspect the bank 2 EGR cooler bypass actuator connector and harness for damage or wiring that may be touching ground.
3. Check the bank 2 bypass mechanism for binding or a mechanical jam that could strain its actuator.
4. Test the bank 2 actuator control wire for a short to ground following the manufacturer's procedure.
5. If the wiring and mechanism are sound, test the bank 2 actuator and its driver using the manufacturer's diagnostic procedure.

Common fixes

• Repair the bank 2 control wire if it is shorted to ground.
• Free or repair the bank 2 bypass mechanism if it is jammed.
• Replace the bank 2 actuator if it draws excessive current internally.
• Clear the code and verify that the bank 2 actuator operates without triggering driver protection.

Can I keep driving?

If the engine runs normally, limit hard use and arrange diagnosis because reduced power may occur as EGR control is affected. Stop if the engine overheats or develops severe drivability problems.