P0141
DTC P0141 O2 Bank 1 Sensor 2 Heater
Circuit Description
In order to control emissions, a catalytic converter is used to convert harmful emissions into harmless water vapor and carbon dioxide.
The powertrain control module (PCM)/Engine control module (ECM) has the ability to monitor this process by using a Heated Oxygen Sensor (HO2S 2). The HO2S 2, located in the exhaust stream past the catalytic converter, produces an output signal which indicates the storage capacity of the catalyst; this in turn indicates the catalyst's ability to convert exhaust emissions effectively. If the catalyst is functioning properly, the HO2S 2 signal will be far less active than the signal produced by the Oxygen Sensor (O2S 1).
If the O2S 1 pigtail wiring, connector, or terminal is damaged, the entire O2S 1 assembly must be replaced. Do not attempt to repair the wiring, connector, or terminals. In order for the sensor to function properly, it must have a clean air reference provided to it. This clean air reference is obtained by way of the O2S 1 wire(s). Any attempt to repair the wires, connector, or terminals could result in the obstruction of the air reference and degrade the O2S 1 performance.
Conditions for Setting the DTC
- The Engine Coolant Temperature (ECT) is less than -40 °C (-40 °F).
- The Intake Air Temperature (IAT) less than 40 °C (104 °F).
- The ignition voltage is between 11 and 18 volts.
- The average airflow is less than 14 g/sec.
- The TP sensor is greater than 50% with a 0.4 second delay.
Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The PCM/ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.
- The coolant fan turns ON.
Conditions for Clearing the MIL/DTC
- The MIL will turn off after three consecutive ignition cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- The DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
An intermittent may be caused by a rubbed-through wire insulation or a wire contacting the exhaust.
Check for a poor connection or a damaged harness - inspect the harness connectors for the following conditions:
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminal to wire connection
- Damaged harness
Steps 1 - 14:
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
2. This step determines if DTC P0141 is the result of a hard failure or an intermittent condition. With the ignition ON, engine OFF, the HO2S 2 voltage displayed on the scan tool should change within several minutes towards a or 1 volt, indicating that the heater is working properly.
3. Probing terminal D of the HO2S 2 connector verifies if voltage is available to the HO2S 2 heater.
4. If voltage is available at the connector, it becomes a good voltage source to check for a ground at terminal C.
5. Determines if voltage is not available at the HO2S 2 due to an open O2 fuse or open ignition feed circuit. If the fuse is open, determine if it was due to a short in the ignition feed circuit before replacing the fuse.