Diagnostic Trouble Code (Dtc) P0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1) - Isuzu 1999 RODEO Workshop Manual

6E1–156 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DIAGNOSTIC TROUBLE CODE (DTC) P0135 O2 SENSOR HEATER CIRCUIT
Circuit Description
Heated oxygen sensors are used to minimize the amount
of time required for "Closed Loop" fuel control operation
and to allow accurate catalyst monitoring. The oxygen
sensor heater greatly decreases the amount of time
required for fuel control sensors Bank 1 HO2S 1 and Bank
2 HO2S 1 to become active. Oxygen sensor heaters are
required by catalyst monitor sensors Bank 1 HO2S 2 and
Bank 2 HO2S 2 to
temperature which allows accurate exhaust oxygen
content readings further from the engine.
The powertrain control module (PCM) will run the heater
test only after a cold start (determined by engine coolant
and intake air temperature at the time of start–up) and
only once during an ignition cycle. When the engine is
started the PCM will monitor the HO2S voltage. When the
HO2S voltage indicates a sufficiently active sensor, the
PCM looks at how much time has elapsed since start–up.
If the PCM determines that too much time was required
for the Bank 1 HO2S 1 to become active, a Diagnostic
Trouble Code P0135 will set. DTC P0135 is a type B
code.
Conditions for Setting the DTC
f No related Diagnostic Trouble Codes.
f Intake air temperature (IAT) is less than 32°C (90°F)
at start–up.
MALFUNCTION (BANK 1 SENSOR 1)
maintain a sufficiently high
f Engine coolant temperature (ECT) is less than 32°C
(90°F) at start–up.
f IAT and ECT are within 5°C (9°F) of each other at
start–up.
f Ignition voltage is between 11 and 16.6 V.
f Average calculated air flow is less than 18 g/second
during sample period.
f Throttle angle is less than 40%.
f Bank 1 HO2S 1 voltage does not change more than
148 mV from the bias voltage (between 400 mV and
500 mV) for a longer amount of time than it should. The
maximum amount of time to come up to operating
range is 240 seconds. This warm–up time depends on
the engine coolant temperature at start–up and intake
air temperature at start–up.
Action Taken When the DTC Sets
f The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.
f The PCM will store conditions which were present
when the Diagnostic Trouble Code 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.
D06RX046