DTC Advanced Diagnostics: P2237: General Description

Courtesy of HONDA, U.S.A., INC.

Rear air/fuel ratio (A/F) sensor (bank 1, sensor 1) is installed in the exhaust manifold and detects oxygen content in the exhaust gas. Rear A/F sensor (bank 1, sensor 1) transmits a signal to the powertrain control module (PCM), and the PCM controls fuel injection duration by comparing the target air/fuel ratio with the rear A/F sensor (bank 1, sensor 1) signal. Rear A/F sensor (bank 1, sensor 1) is composed of detection element, reference oxygen chamber, diffusion chamber, and heater, etc., and enables feedback control of all ranges. If the rear A/F sensor (bank 1, sensor 1) signal AFCB1 or AFVB1 is open circuit, no current will flow to the sensor. Therefore, the element impedance will not decrease even if the element is active. If the element impedance is a set value for a specified duration, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type