Diagnostic Trouble Code (Dtc) P0140 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2); (Bank 1 Sensor 2) - Isuzu 1999 RODEO Workshop Manual

DIAGNOSTIC TROUBLE CODE (DTC) P0140 O2 SENSOR CIRCUIT NO
Circuit Description
To control emissions of hydrocarbons (HC), carbon
monoxide (CO), and oxides of nitrogen (NOx), a
three–way catalytic converter is used. The catalyst within
the converter promotes a chemical reaction which
oxidizes the HC and CO present in the exhaust gas,
converting them into harmless water vapor and carbon
dioxide. The catalyst also reduces NOx, converting it to
nitrogen. The powertrain control module (PCM) has the
ability to monitor this process using the Bank 1 HO2S 1
and the Bank 1 HO2S 2 heated oxygen sensors. The
Bank 1 HO2S 2 sensor produces an output signal which
indicates the amount of oxygen present in the exhaust
gas entering the three–way catalytic converter. The Bank
1 HO2S 2 sensor produces an output signal which
indicates the oxygen storage capacity of the catalyst; this
in turn indicates the catalyst's ability to convert exhaust
gases efficiently. If the catalyst is operating efficiently, the
Bank 1 HO2S 1 signal will be far more active than that
produced by the Bank 1 HO2S 2 sensor. If the Bank 1
HO2S 2 signal voltage remains between 400 mV and 500
mV for an extended period of time, Diagnostic Trouble
Code P0140 will be set. DTC P0140 is a type A code.
Conditions for Setting the DTC
f No related Diagnostic Trouble Codes.
f Engine run time is longer than 120 seconds.
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
ACTIVITY DETECTED (BANK 1 SENSOR 2)
f Oxygen sensor heater is functioning properly, and the
oxygen sensor has reached operating temperature.
f Engine is operating in "Closed Loop".
f Bank 1 HO2S 2 signal voltage remains between 426
mV and 474 mV for a total of 106.25 seconds over a
125–second period of time.
Action Taken When the DTC Sets
f The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
f The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
f The PCM will turn the MIL OFF on the third consecutive
trip cycle during which the diagnostic has been run and
the fault condition is no longer present.
f A history Diagnostic Trouble Code P0140 will clear
after 40 consecutive warm–up cycles have occurred
without a fault.
f Diagnostic Trouble Code P0140 can be cleared by
using the Scan Tool's "Clear Info" function.
Diagnostic Aids
Check for the following conditions:
f Poor connection or damaged harness – Inspect the
harness connectors
improper mating, broken locks, improperly formed or
6E1–165
D06RX047
for backed–out terminals,