P2BAA Possible Causes
- Faulty NOx sensors
- NOx sensor wiring harness open or shorted
- Poor electrical connection in NOx sensor circuit
- Diesel particulate filter (DPF)
How to Fix P2BAA Code
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
Illuminated engine light (or service engine soon warning light)
P2BAA Meaning
The selective catalytic reduction system reduces nitrogen oxide (NOx) emissions by injecting a measured amount of diesel exhaust fluid or reductant into the exhaust gas stream entering the diesel particulate filter (DPF). In the selective catalytic reduction catalyst, the reductant reacts with NOx to form nitrogen, carbon dioxide, and water vapor. The upstream and downstream NOx sensors provide the engine control module (ECM) with NOx levels from engine output and exhaust output.
The ECM uses the 2 NOx sensors to control exhaust NOx levels. The NOx sensor measures the amount of NOx and oxygen in the exhaust system. The first NOx sensor is located at the turbocharger outlet and monitors engine NOx emissions. The second NOx sensor is located in the DPF which monitors NOx levels exiting the DPF. The ECM varies the amount of reductant added by adjusting the reductant injector duty cycle in response to changes in engine exhaust NOx levels.