Check engine code P0138

I would replace the engine thermostat and clear the codes and drive it for a few days. P0136 is engine does not reach operating temperature

p0138 - oxygen sensor circuit high voltage.
need to check or replace O2 sensor

Hi there:
Both codes refer at O2 sensor...


DTC P0141 - O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
This code means that the heated circuit in the oxygen sensor on bank 1 decreases time needed to enter closed loop. As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. It the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0141. See also: P0135 (Bank 1, Sensor 1).



You will likely notice poor fuel economy the illumination of the Check Engine Light.



A code P0141 may mean that one or more of the following has happened:
open or short to ground in the wiring harness
O2 heater circuit wiring high resistance
O2 heater element resistance is high
Internal short or open in the heater element
Note: Typically a failed catalytic converter does not cause this code. You're more likely to see a P0420 code for a failed converter.


Possible Solutions:
Replace oxygen sensor (cannot repair open or short that occurs internally to sensor)
Repair short or open or high resistance in wiring harness or harness connectors





DTC P0138 - O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor2)
The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. Ho2S 2 signal is less active than signal produced by front oxygen sensor. This code sets when HO2 Sensor voltage is greater than 999 mV for more than 2 minutes (time depends on model. Could be as high as 4 minutes)



There may be no noticeable symptoms except for MIL illumination. Possible high fuel pressure can over rich the system.


A code P0138 may mean that one or more of the following has happened:
Faulty O2 sensor
Short to battery voltage in O2 sensor signal circuit
High fuel pressure (not as likely)


Here are some potential solutions:
Replace O2 sensor
Repair short to battery voltage in o2 sensor signal circuit.


Hope this helps; also keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using Fixya, and have a nice day.

Hi Larry:
DTC P0138 - O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor2)
The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. Ho2S 2 signal is less active than signal produced by front oxygen sensor. This code sets when HO2 Sensor voltage is greater than 999 mV for more than 2 minutes (time depends on model. Could be as high as 4 minutes)

There may be no noticeable symptoms except for MIL illumination. Possible high fuel pressure can over rich the system.

A code P0138 may mean that one or more of the following has happened:
Faulty O2 sensor
Short to battery voltage in O2 sensor signal circuit
High fuel pressure (not as likely)

Here are some potential solutions:
Replace O2 sensor
Repair short to battery voltage in o2 sensor signal circuit

Check it; hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Trouble codes are normaly 4 digits with a "P" or "B" before it. I am gonna assume that you meant P0138 and P0401:
P0138 is Oxygen Sensor Circuit High Voltage (Bank 1, Sensor 2)
P0401 is Exhaust Gas Recirculation Flow Insufficient Detected

A code P0138 may mean that one or more of the following has happened:

• Faulty O2 sensor
• Short to battery voltage in O2 sensor signal circuit
• High fuel pressure (not as likely)

Possible Solutions Here are some potential solutions:

• Replace O2 sensor
• Repair short to battery voltage in o2 sensor signal circuit

for info on the P0401:
http://www.obd-codes.com/p0401

The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. Ho2S 2 signal is less active than signal produced by front oxygen sensor. This code sets when HO2 Sensor voltage is greater than 999 mV for more than 2 minutes (time depends on model. Could be as high as 4 minutes)
There may be no noticeable symptoms except for MIL illumination. Possible high fuel pressure can over rich the system.
A code P0138 may mean that one or more of the following has happened:

• Faulty O2 sensor
• Short to battery voltage in O2 sensor signal circuit
• High fuel pressure (not as likely)

Here are some potential solutions:

• Replace O2 sensor
• Repair short to battery voltage in o2 sensor signal circuit

P0138 - O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor2)

The Heated Oxygen Sensor (2) located rear of catalytic converter produces an output signal relative to oxygen storage capacity of catalytic converter. Ho2S 2 signal is less active than signal produced by front oxygen sensor. This code sets when HO2 Sensor voltage is greater than 999 mV for more than 2 minutes (time depends on model. Could be as high as 4 minutes)

Symptoms: There may be no noticeable symptoms except for MIL illumination. Possible high fuel pressure can over rich the system.

Causes: A code P0138 may mean that one or more of the following has happened:
* Faulty O2 sensor
* Short to battery voltage in O2 sensor signal circuit
* High fuel pressure (not as likely)

Possible Solutions: Here are some potential solutions:
* Replace O2 sensor
* Repair short to battery voltage in o2 sensor signal circuit

Hope helps (remember to rate and comment this).

When the engine is cold place a piece of paper in front of exhaust pipe and see if that white smoke contains oil in it.
If it is oil it means a cracked block or worn rings in engine which means very expensive repair or replacement of engine.

If steam is coming out exhaust then water is escaping from the head gasket into the fuel chamber of the piston and is being ignited and turned into steam. A blown head gasket or worse a warped engine head may be the cause. A engine compression test would rule this out as a cause .

Could be just the sensor, could be a bad fuse, or could be bad wiring. Change the sensor, check the fuse, and check wiring, or reverse order.

What kind of vehicle? I may have the book here.