I believe "reductant" is the DEF fluid and your pump isn't functioning properly. Check your DEF spray nozzle, it could be clogged with urea deposits, causing the issue.
When I had issues with my DEF system (don't recall the code), I cleaned the nozzle and mount hole with steam*, cleared the code and problem solved. Lately I've been using a 50/50ish mix of the DEF with anti-deposit additive and regular (read: less expensive) DEF without problems.