Daewoo Matiz (2003 year). Manual - part 46
1F – 94 ENGINE CONTROLS
MAA1F140
DIAGNOSTIC TROUBLE CODE (DTC) – P0137 HEATED OXYGEN SENSOR LOW
VOLTAGE
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 44 and
13. The oxygen (O
2
) 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 O
2
sensor is like
an open circuit and produces no voltage when it is below
360
°
C(600
°
F). An open O
2
sensor circuit or a cold O
2
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 heated oxygen sensor voltage is below 0.07V for
at least 40 seconds.
D
DTCs P0107, P0108, P0117, P0118, P0122, P0123,
P0335, P0336, P0341, P0342, P0400, P0404,
P0405, P0406 are NOT SET.
(Case B)
D
The engine controls system is in closed loop.
D
Engine speed is less than 6,000rpm.
D
The heated oxygen sensor voltage is between 0.352
and 0.499 at least 60 seconds.
Action Taken when the DTC Sets
D
Emission related.
D
“Armed” after two trip with a fail.
D
“Disarmed” after one trip with a pass.
D
MIL on if failure is detected in three consecutive trips.
D
Stores a History DTC on the third consecutive with a
fail (The DTC will be armed after the second fail).
D
Stores a Freeze Frame on the third consecutive trip
with a fail (if empty).
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.
Diagnostic Aids
D
Normal scan tool voltage varies between 0.1 volts
and 0.9 volts while in closed loop.
D
Inspect the oxygen (O
2
) sensor wire. The O
2
sensor
may be positioned incorrectly and contacting the ex-
haust manifold.
D
Check for an intermittent ground in the wire between
the O
2
sensor and the engine control module.
D
Perform an injector balance test to determine if a re-
stricted fuel injector may be causing the lean condi-
tion.
D
Vacuum of crankcase leaks will cause a lean running
condition.
D
An exhaust manifold gasket leak of a cracked ex-
haust manifold may cause outside air to be pulled into
the exhaust and past the sensor.