What makes fault code P0141 different from the others? What makes fault code P0141 different from others?Fault Code P0141 is ‘Oxygen Sensor Heating Circuit Malfunction (Bank 1, Sensor 2)’. This fault code indicates that the oxygen sensor heater circuit (downstream), located in the first row of the engine, is malfunctioning.
Row 1 refers to the row of the engine where the 1 cylinder is located. In Ford vans Bank 1 is on the passenger’s side. However, in other brands like Chevy and Dodge, it can be found on the driver’s. Before you begin to fix the problem, it is crucial to locate Bank 1. Sensor 2 is located either in the middle or behind the catalytic convertor (the converter nearest to the engine) of the catalytic conversion.
Oxygen sensors monitor the oxygen content of exhaust gases that enter and exit the catalytic convertor and transmit this information to vehicle computers (ECM/PCM/ECU).
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Data from the sensor 1/pre-converter (upstream oxygen sensor) is used by the ECM to fine-tune engine air-fuel mix. The downstream oxygen sensor (Sensor 2, after the catalytic convertor) is used to test the catalytic conversion’s efficiency. Most people, including some mechanics, don’t know that the ECM uses the downstream O2 sensor when the upstream sensor is inconsistent.
The oxygen sensors should be activated as soon as possible when the engine is started (within a minute). For this to happen, the sensors must reach a specific temperature. The O2 sensor with one wire will not work until the exhaust system has warmed up and the zirconia component reaches 600°F.
Heated oxygen sensors were introduced. Heated oxygen sensors have four wires. Two of the wires will always be the same color, which is usually white or brown. Two wires are used to heat a sensor and receive voltage from a relay. The two other wires transmit the data required by the powertrain module.
The O2 sensor has a heating element in the middle, similar to the glow plug of a diesel engine. The heater cannot be seen without removing the O2 sensor. It has a resistance value of 6 ohms when cold; it increases as it warms up.
The ECM controls and measures the current flowing through the heater by measuring the voltage at ground that it provides. The ECM will generate the P0141 error code if there is no current flowing to the heater. It will also illuminate the engine fault lamp.
What are the causes of fault code P0141?
- Faulty oxygen heater (most common).
- Circuit problems (e.g. damaged wiring, loose connectors – quite common).
- ECM related issues (e.g. software that requires an update, very rare)
Note: This code cannot be caused by a faulty catalytic convert. The P0420 code is generated if the catalytic convert is faulty.
What are the symptoms of fault code P0141?
- Engine fault light illuminated
- High emission values
- Fuel consumption increases due to engine running on rich mixture
- Misfiring engine
How to Fix Fault Code P0141?
- Bank 1 Sensor 2, Replacement of the O2 Sensor (after the catalytic convertor)
- Repair and replace the cable and connectors that lead to the O2 Sensor for Bank 1 sensor 2.
- Replace the fuse in the circuit for the heater of the O2 sensor
Is the P0141 Fault Code Important?
The O2 sensor must be working correctly for the ECM to control the injectors, and deliver the correct amount of fuel into the combustion chamber. The ECM can remain in an open-loop until the fault has been repaired. The engine will run richer and use more fuel. The vehicle’s emissions also increase. The fault should therefore be treated seriously and fixed as soon as possible.
