DTC P0139 Or P0159: Rear Or Front Secondary Ho2S (Slow Response)

If the scan tool indicates DTC P0139, a slow response problem in the rear secondary HO₂ S (bank 1, sensor 2) circuit may exist. If the scan tool indicates DTC P0159, a slow response problem in the front secondary HO₂ S (bank 2, sensor 2) circuit may exist. See Fig 1 .

Fig 1: Secondary HO₂ S (Slow Response) Diagnostic Flow Chart

Courtesy of AMERICAN HONDA MOTOR CO., INC.