Code result
P20CA
Reductant Injection Air Pressure Leakage
Moderate severity
What it means
A leak has been detected in the air-assist branch of the DEF system — pressure decays faster than allowed when the air pump shuts off.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Cracked air line or fitting
highOne of the most commonly reported causes for this code — check this first.
Air pressure control valve seat leaks
mediumA plausible cause — test and verify before replacing parts.
Related help
Get the full diagnosis
Add your vehicle and see step-by-step repair help, recalls, and TSBs in Wrenchify.
Diagnose P20CA freeNo credit card required