DTC Detection Logic

The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen storage capacity of the three way catalyst (manifold) causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the maximum voltage of the sensor is sufficiently high during the various driving condition such as fuel-cut.

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

VOLTAGE SPECIFICATION

(a):

0.71 V

P0137 HO2S2 - DTC DESCRIPTION

DTC		M.U.T.-III SE screen terms (Trouble diagnosis content)	DTC detection condition
P0137	00	O2 sensor bank 1 sensor 2 (O2 sensor circuit low voltage bank 1 sensor 2)	Diagnosis condition	-
			Signal (terminal)	Heated oxygen sensor 2 signal
			Threshold	The maximum voltage from the sensor does not reach the specified voltage ECM detects the heated oxygen sensor 2 circuit is short to ground.
			Diagnosis delay time	^-