P0038

Wiring Diagram:

HO2S Heater Control Circuit High Voltage Bank 1 Sensor 1:

P0038- HO2S HEATER CONTROL CIRCUIT HIGH VOLTAGE BANK 1 SENSOR 2
The heated oxygen sensor (HO2S) bank 1 sensor 2 is threaded into the front exhaust pipe directly behind the cylinder 1, 3, 5 pre-converter (cylinders 1, 3, 5 are closest to front of dash). The sensor is used by the ECM to determine the oxygen storage capability of the pre-converter. The sensor is equipped with a heater element to provide additional heat to speed up sensor activation time. The ECM controls the heater by pulsing circuit 151 to ground. When the heater is commanded Off (circuit not grounded), the voltage level at the ECM should be high (ignition voltage). When the heater is commanded On (circuit grounded), the voltage level at the ECM should be low. The ECM heater feedback circuit uses a pull-up voltage (2.6-4.6 volts), which allows the ECM to individually differentiate between an open, short to ground or short to voltage. DTC P0038 will set if the ECM detects higher than normal feedback voltage when HO2S bank 1 sensor 2 heater heater is commanded On with engine cranking/running.

DTC PARAMETERS
DTC P0038 will set if HO2S bank 1 sensor 2 heater feedback voltage is greater than 4.6 volts when heater is commanded On when:
^ Condition exists for longer than 0.5 seconds
^ Engine speed is greater than 40 rpm Battery voltage is between 7.5 and 15.0 volts

DTC P0038 diagnostic runs continuously once the above conditions have been met.

P0038 is a type B DTC

DIAGNOSTIC AIDS
Heater element resistance: 7.0-20.2 ohms