GM 19211437 Sensor,Exhaust Oxygen

In L4 engines, the oxygen sensor is a screw-in one located at the exhaust manifold and in V6 engines, it is on the exhaust pipe. For this reason, it is harder to unscrew the sensor when the engine is cold and it would be better if you did it while the engine is operating. In that case, jack up the front of the vehicle and rest it on jack stands to create enough room for your work. On L4 models, extract air cleaner. Oxygen sensor electrical connector should be removed by detaching its terminals. Apply a penetrating oil to the threads of the oxygen sensor during installation ensuring that it penetrates for approximately 5 minutes. Unscrew and remove carefully. Be careful not to damage threads in exhaust manifold/pipe while removing it. Before installing new sensor, coat its threads thoroughly with an anti-seize compound then install it properly. Torque carefully to 30 ft-lb (4.1 m-kg). Reconnect electrical connector to sensor itself as before mentioned. After replacing oxygen sensor reinstall air cleaner on L4 models and lower car on V6models to ground level.When replacing an oxygen sensor, always reset 'sensor' light on dash board panel.

Most components in 1989 through 1991 Geo Metro models have an extended warranty coverage from the government which makes it difficult to perform component checks or replacements during the warranty period. Both sensors found in electrical position determine exhaust gas oxygen levels within the exhaust manifold and catalytic converter which detects emission levels respectively where circuit failures produce code 13. A failure within the TBI unit coolant temperature sensor thermistor will trigger a code 14 or 15 while a check requires resistance tests with an ohmmeter and replacement with Teflon tape or thread sealant to stop leaks. A failure in the manifold air temperature (MAT) sensor located in the air cleaner housing produces a code 24 which should be diagnosed by a dealer. A faulty manifold absolute pressure sensor cannot be repaired thus it requires complete unit replacement because it transforms the manifold pressure fluctuations into an electronic signal for fuel control through ECM. Manual transaxle cars use a throttle switch (TS) to check throttle valve angle whereas automatic transaxle vehicles utilize a throttle position sensor (TPS) to accomplish the same function. Both devices trigger error codes 21 or 22 that demand professional diagnostics for proper fix. A failure of the vehicle speed sensor (VSS) which is integrated with the speedometer causes a pulsing voltage signal to the ECM for speed calculation and produces error code 24. This diagnosis requires professional attention from a dealer. Engine speed calculation and device control operations derive from the crank angle sensor which exists as a component of the distributor to produce alternating voltage pulses.

Monitoring of the oxygen situation is performed with the oxygen sensor located in the exhaust manifold through the feedback to the ECM; the ions can vary an air/fuel mixture and instantly adjust the ratio for the maximum efficiency and minimal emission, with the optimum coefficient of 14.7 to 1. If the sensor is open, then it develops a Code 13, a low or high voltage issue causes the engine to run on open loop creating Codes 44 and 45. For the sensor to work correctly it must have good electrical connection; it must not be choked with excess air; it must come to operating temperature of about 600 °F (315°C) and should preferably use unleaded fuel. This requires a sharp focus during servicing not to damage the permanently attached pigtail and connector, do not let contaminants get near the electrical parts, do not use cleaning solvents, and ensuring that silicone boot is properly placed. In case of replacement, the sensor is fitted in a different location depending on the type of engine and must not be replaced if the engine is cold or below 120°F. The location of the silicone boot should be observed and the sensor pulled back very gently just to avoid stripping the threads. To facilitate easy unfastening at a later stage, some threads on the sensor require an anti-seize compound with the sensor subsequently tightened to the required torque and connected to the main engine wiring harness.

The oxygen sensor is located in the exhaust manifold or pipe and can be accessed from under the hood. It has a permanently attached pigtail and connector that should not be removed or damaged. Keep the sensor clean and handle it gently. Do not use cleaning solvents on it. The silicone boot must be correctly installed to prevent melting and ensure proper operation. Warm the engine to at least 120 degrees F before removing the sensor. Disconnect the electrical connector and carefully unscrew the sensor from the exhaust manifold. Use a special anti-seize compound on the threads for future removal. Install the sensor, tighten it to 30 ft-lbs, and reconnect the electrical connector.

These codes do not necessarily indicate a faulty sensor; they may reflect issues like a dirty air filter or vacuum leak instead.

The exhaust oxygen sensor is positioned in the exhaust stream to monitor the oxygen content in the exhaust gas.

If the sensor is difficult to loosen, running the engine briefly can help.

An oxygen sensor is a device that produces an electrical voltage when exposed to the oxygen in the exhaust gases.

Care must be taken to not remove the permanently attached pigtail and connector, keep contaminants away from the electrical connector and sensor end, avoid cleaning solvents, handle the sensor gently, and ensure the silicone boot is correctly positioned.

Oxygen sensors require an operating temperature of around 600°F. Below this temperature during warm-up, the ECM/PCM operates in open-loop mode and doesn't use the sensor's feedback. Heating elements in the sensors help reach operating temperature quickly.

When replacing a post-converter sensor, ensure the vehicle is securely raised, disconnect the electrical connector, unscrew the sensor using the appropriate tool, apply anti-seize compound to the threads, and secure it while reattaching the electrical connector before lowering the vehicle.

The oxygen sensor in the exhaust monitors oxygen content. To check it, you can check its millivolt signal while the engine warms up. It is also important to inspect the oxygen sensor heater and ensure it receives proper voltage.

The oxygen sensor in the exhaust monitors oxygen content. To check it, you can check its millivolt signal while the engine warms up. It is also important to inspect the oxygen sensor heater and ensure it receives proper voltage.

Before unscrewing the oxygen sensor, a penetrating oil should be applied to the threads and allowed to soak in for about 5 minutes.

Dual Hall effect sensors operate similarly to single Hall effect sensors but provide two separate ON/OFF signal patterns.

On L4 models, the air cleaner should be removed before removing the oxygen sensor.