1F–84 ENGINE CONTROLS
DAEWOO M-150 BL2
MAA1F130
DIAGNOSTIC TROUBLE CODE (DTC) – P0131 OXYGEN SENSOR LOW
VOLTAGE
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450m volts between the ECM terminals 44 and
13. The oxygen (O2) sensor varies the voltage within a
range of about 1volt if the exhaust is rich, down to about
100mm volts if the exhaust is lean. The O2 sensor is like
an open circuit and produces no voltage when it is below
350°C(600°F). An open O2 sensor circuit or a cold O2
sensor causes “open loop” operation.
Conditions for Setting the DTC
(Case A)
D The engine controls system is in closed loop.
D Engine speed is less than 6,000rpm.
D The oxygen sensor voltage is below 0.07V for at least
40seconds.
D DTCs P0107, P0108, P0117, P0118, P0122, P0123,
P0335, P0336, P0341, P0342, P0400, P0404,
P0405, P0406, P0445, P0444 are NOT SET.
(Case B)
D The engine controls system is in closed loop.
D Engine speed is less than 6,000rpm.
D The oxygen sensor voltage is between 0.352 and
0.499 at least 10seconds.
Action Taken when the DTC Sets
D The Malfunction Indicator Lamp (MIL) will illuminate.
D The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.
D A history DTC is stored.
Conditions for Clearing the MIL/DTC
D The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
D A history DTC will clear after 40 consecutive warm-up
cycles without a fault.
D DTC(s) can be cleared by using the scan tool.
D Disconnecting the ECM battery feed for more than 10
seconds.
Diagnostic Aids
Normal scan tool voltage varies between 0.1volts and
0.9 volts while in closed loop.
Inspect the oxygen (O2) sensor wire. The O2 sensor
may be positioned incorrectly and contacting the ex-
haust manifold.
Check for an intermittent ground in the wire between the
O2 sensor and the engine control module.
Perform an injector 2alance test to determine if a re-
stricted fuel injector may be causing the lean condition.
Vacuum of crankcase leaks will cause a lean running
condition.
An exhaust manifold gasket leak of a cracked exhaust
manifold may cause outside air to be pulled into the ex-
haust and past the sensor.
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