P0038

Diagnostic Chart:

Schematic:

The rear oxygen sensors are equipped with heater to asist in ramping up and maintaining a minimal operating temperature. The ECM diagnoses the heater and it's related wiring by continuously monitoring electrical current. The ECM will set this DTC when the signal being received is higher than expected.

DTC PARAMETERS
This DTC will set when:
^ Engine speed greater than 40 rpm
^ Battery voltage is between 7.5 and 15 volts

DTC P0038 is a (type B) DTC

DIAGNOSTIC AIDS
To locate an intermittent problem use Scan tool to monitor the HO2S Heater Bn 1 Sen. 2 voltage with engine idling at normal operating temperature.

Wiggling wires while monitoring HO2S Heater Bn 1 Sen. 2 voltage may locate area where a short to voltage exists.

Review failure record information to check if vehicle was running rich in a decel (TP angle equals zero percent, HO2S Bank 1 Sensor 2 reading less than 0.8) when DTC was set. If so, check for a possible rich condition.