If hydrogen is obtainable from the exhaust, the TWC/TWNSC may also make ammonia, which reduces the essential amount of urea injection; It doesn't detect and supply an warn in each problem. It is actually the driving force's responsibility to stay notify continually. See Owner’s Handbook for further details and constraints. https://emilioudlud.bloggazza.com/26239694/facts-about-water-for-fuel-revealed