P0144 02 Sensor Circuit High Voltage (Bank 1 Sensor 3)
OBD-II Trouble Code Technical Description
02 Sensor Circuit High Voltage (Bank 1 Sensor 3)
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model.
The catalytic converter is used to lower harmful emissions. To ensure proper operation, there is an O2 sensor located behind the catalyst that monitors the oxygen content of the exhaust after the cat. The PCM (Powertrain Control Module) then compares the post-cat reading to the pre-cat readings to determine if the catalyst is working properly.
A P0144 refers to a fault at the post-cat o2 sensor, indicating that the signal voltage is too high. The o2 sensor is a four wire sensor. Two wires are dedicated to the heating element and two wires are dedicated to the sensor. The heating element should have battery voltage on one wire with key on engine off and ground should be present on the other. The PCM supplies a reference voltage to the o2 sensor which the sensor varies according to oxygen content in the exhaust. It is capable of varying between approximately 0.1 and 0.9 volts. This variance in the voltage is monitored by the PCM. The PCM also supplies a ground to the sensor. P0144 means that the voltage was too high on the signal circuit.
Symptoms
Symptoms of a P0144 DTC may include:
Causes
Potential causes of an P0144 code include:
Possible Solutions
Start the engine and observe the Bank 1 Sensor 3 (a.k.a. 1/3) o2 sensor voltage. You may need to raise the idle up until the o2 sensor starts switching.
If it is stuck high, or close to 1 volt and the voltage doesn’t vary, then check for a good ground on both the heater element and the sensor. Also check that the heater element is being supplied good battery voltage. No heater operation can cause a sluggish sensor.
If the grounds are good and the battery voltage is present, then jumper the sensor’s signal wire to the sensor’s ground wire. Now the scan tool should read low or near zero volts. If it does, the wiring is good. Replace the bank 1/3 o2 sensor. If jumpering the signal wire to the ground doesn’t lower the voltage, then check the o2 sensor wiring harness. Make sure there is no contact with hot exhaust components. Ensure good wiring harness connections. If the wiring checks out, then reperform the previous wiring harness checks at the PCM connector.
If now the 1/3 o2 sensor reading drops, then there is a wiring problem that isn’t visible. Open the harness and visually inspect the wiring for problems. But if the result is the same, then the PCM may be bad.
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"Delete Error Code Permanently, Disable DTC Error Code Function for p0144 in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC p0144 and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.
Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p0144.
