Symptoms

- Engine Light ON (or Service Engine Soon Warning Light) - High Fuel Consumption - Excessive Smoke from Exhaust

Possible Causes

- Rear Heated Oxygen Sensor Bank 1 harness is open or shorted - Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection - Faulty Rear Heated Oxygen Sensor Bank 1 - Inappropriate fuel pressure - Faulty fuel injectors - Intake air leaks may be faulty - Exhaust gas leaks

When Detected

Current amperage in the rear heated oxygen sensor heater circuit is out of the normal range.

Tech Notes

Replacing the rear O2 Sensor bank 1 usually takes care of the problem.

Description

The heated oxygen sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

Information For Specific Makes

P0141 ACURA P0141 HONDA P0141 BMW P0141 CHRYSLER P0141 JEEP P0141 DODGE P0141 FORD P0141 HYUNDAI P0141 ISUZU P0141 KIA P0141 LEXUS P0141 TOYOTA P0141 SCION P0141 MAZDA P0141 MITSUBISHI P0141 VOLKSWAGEN P0141 AUDI P0141 SATURN