Sebring Convertible V6-2.5L VIN H (1997)
Downstream Heated Oxygen Sensor
DOWNSTREAM OXYGEN SENSOR
The downstream heated oxygen sensor threads into the outlet pipe at the rear of the catalytic convertor. The downstream heated oxygen sensor
input is used to detect catalytic convertor deterioration. As the convertor deteriorates, the input from the downstream sensor begins to match the
upstream sensor input except for a slight time delay. By comparing the downstream heated oxygen sensor input to the input from the upstream
sensor, the PCM calculates catalytic convertor efficiency.
CIRCUIT OPERATION
Circuit A14 is connected to the BUS bar in the Power Distribution Center (PDC), which connects to battery voltage. The contact side of the
Automatic Shut-Down (ASD) relay connects circuit A14 and circuit A142. A 20 amp fuse, located in cavity 5 of the PDC, protects circuits A14
and A142.
Circuit A14 also supplies voltage to the coil side of the ASD relay. The Powertrain Control Module (PCM) controls the ground path circuit for the
coil side of the ASD relay on circuit K51. Circuit K51 connects to cavity 67 of the PCM.
The A142 circuit also splices to cavity 6 of the PCM connector. The input by circuit A142 tells the PCM that the ASD relay is energized.
The A142 circuit supplies voltage for the upstream heated oxygen sensor and circuit F142 supplies voltage to the downstream heated oxygen
sensor. The F142 circuit is protected by a 10 amp fuse located in cavity 1 of the PDC. Power for the fuse is supplied by circuit A142.
Circuit K41 delivers the signal from the upstream heated oxygen sensor to the PCM. Circuit K41 connects to cavity 30 of the PCM connector.
Circuit K141 delivers the signal from the downstream heated oxygen sensor to the PCM. Circuit K141 connects to cavity 51 of the PCM
connector.
The PCM provides a ground for the upstream (left) and downstream (right) heated oxygen sensor signals (circuits K41 and K141) through circuit
K4. Circuit K4 connects to cavity 43 of the PCM connector.
Circuit Z1 provides the ground path for the heater circuits in the sensors. This ground terminates at the right frame rail.
HELPFUL INFORMATION
Circuit A142 splices to supply voltage to the fuel injectors, ignition coil, ASD relay, generator, and the EGR solenoid. The PCM controls the
ground path for each of the components powered by circuit A142.
Circuit K4 splices to supply ground for the signals for the following:
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Intake air temperature sensor
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Engine coolant temperature sensor
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Manifold absolute pressure sensor
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Throttle position sensor
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A/C pressure switch
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Camshaft position sensor
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Crankshaft position sensor
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Vehicle speed sensor
