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P0138 Diagnostic Trouble Code Discussion for July 2004

Heated Oxygen Sensor (Bank 1 Sensor 2) Circuit High Voltage

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Trouble Ticket Help Requests for DTC P0138
Help Request Posted
1995 Chevrolet Blazer 4.3L MIL Lamp on VIN: 1GNDT13WXS
P0138: 02 Sensor High Voltage bank 1 sensor 2 CAT. ... code P0138 on scanner. Rear o2 sensor bias voltage is over 1 volt when ignition first turned on, drops to .400 after couple minutes while o2 heater warms up. Will not drop any farther. Front o2 sensor bias voltage on scanner near .400 and drops to zero a...
July 29, 2004