P0141

DTC P0141 HO2S Heater Circuit Sensor2




Circuit Description
The HO2S 2, located in the exhaust stream past the catalytic converter, produces an output signal relative to the oxygen storage capacity of the catalytic converter. The PCM can then determine the ability of the catalytic converter to convert the exhaust emissions effectively. The HO2S 2 signal will be far less active than the signal produced by the front Oxygen Sensor 1 (O2S 1).

Conditions for Running the DTC
- Engine Coolant Temperature (ECT) less than 40 °C (104 °F).
- Intake Air Temperature (AT) less than 40 °C (104 °F).
- Difference between ECT and IAT is less than 7 °C (45 °F).
- Throttle Position (TP) is less than 18%.

Conditions for Setting the DTC
HO2S 2 voltage increases less than 150 mV in 100 to 190 seconds.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the malfunction present.
- The PCM will record the operating conditions at the time that the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers.
- A history DTC stores.

Conditions for Clearing the MIL/DTC
- The MIL will turn off after 3 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
- A scan tool can clear the DTCs

Diagnostic Aids
An intermittent could be the result of the following conditions:
- Poor electrical connection
- Moisture in the connector/wiring
- Rubbed through wire insulation
- Broken wire inside of the insulation

Check for a poor electrical connection or a damaged harness. Inspect the harness electrical connectors for the following conditions:
- Improper mating
- Broken locks
- Improperly formed electrical connectors
- Damaged terminals
- A poor terminal to wire connection
- A damaged harness

Replace the entire HO2S 2 assembly (Do not attempt to repair the HO2S2 ) if the following conditions exist:
- Damaged wiring
- Damaged electrical connector
- Damaged terminal(s)

Obstruction of the air reference and degrade HO2S 2 performance could result in any attempt to repair the above conditions.

The HO2S 2 must have a clean air reference in order for the HO2S 2to function properly. This clean air reference is obtained by way of the HO2S 2 wire(s).

Step 1:

Steps 2 - 6:

Steps 7 - 12:

Steps 13 - 14:

Test Description
An example test description follows:
1. The Powertrain OBD System Check prompts you to complete some of the 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 captured when the malfunction occurred. The scan tool stores this data for later reference.
2. This step determines if DTC P0141 is the result of a hard malfunction or an intermittent condition. With the ignition switch ON and the engine OFF, the HO2S 2 voltage displayed on the scan tool should change within several minutes towards 0 or 1 volt, indicating that the heater is working properly.
3. Probing terminal D of the HO2S 2 electrical connector verifies if the voltage is available to the HO2S 2 heater.
4. If the voltage is available at the electrical connector, then the connector becomes a good voltage source to check for a ground at terminal Cycles if.
5. This step determines if the 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 the open fuse was due to a short in the ignition feed circuit before replacing the fuse.