Welcome to the centregalilee.com detailed page on WJ Generation Jeep grand Cherokee oxygen sensors. We have organized together much info as we could find into a helpful post below. Is something incorrect or missing? Please get in touch with us and we’ll resolve it!

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Grand Cherokee WJ oxygen sensor

An O2 sensor is a galvanic battery that provides the PCM with a voltage signal (0-1 volt) inversely proportional to the lot of oxygen in the exhaust. In other words, if the oxygen contents is low, the voltage output is high; if the oxygen content is high the output voltage is low. The PCM offers this details to change injector pulse-width to achieve the 14.7–to–1 air/fuel ratio vital for suitable engine operation and to regulate emissions.

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The O2 sensor must have actually a resource of oxygen from exterior of the exhaust stream for comparison. Existing O2 sensors receive their fresh oxygen (outside air) supply through the O2 sensor instance housing.

Four wires (circuits) are used on every O2 sensor:

12–volt feed circuit for the sensor heater elementGround circuit because that the heater elementLow-noise sensor return circuit to the PCMInput circuit from the sensor ago to the PCM to detect sensor operation
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Grand Cherokee oxygen sensor areas for 4.0 and 4.7 engines

The Oxygen Sensors (O2S) space attached to, and also protrude into the car exhaust system. Depending on the emission package, the automobile may use a total of one of two people 2 or 4 sensors.

Federal Emissions package (4.0L and also 4.7L engines):

Two sensors are used: upstream (referred to together 1/1) and downstream (referred to together 1/2). V this emissions package, the upstream sensor (1/1) is situated just prior to the key catalytic convertor. The downstream sensor (1/2) is located simply after the main catalytic convertor.

California Emissions package (4.0L engine):

On this emissions package, 4 sensors are used: 2 upstream (referred to as 1/1 and 2/1) and also 2 downstream (referred to as 1/2 and 2/2). With this emission package, the rear/upper upstream sensor (2/1) is situated in the exhaust downpipe just before the behind mini-catalytic convertor. The front/upper upstream sensor (1/1) is situated in the exhaust downpipe just prior to the prior mini-catalytic convertor. The rear/lower downstream sensor (2/2) is located in the exhaust downpipe simply after the behind mini-catalytic convertor, and before the main catalytic convertor. The front/lower downstream sensor (1/2) is situated in the exhaust downpipe just after the front mini-catalytic convertor, and also before the main catalytic convertor.

California Emissions parcel (4.7L engine):

On this emissions package, 4 sensors space used: 2 upstream (referred to as 1/1 and also 2/1) and also 2 downstream (referred to as 1/2 and also 2/2). V this emissions package, the appropriate upstream sensor (2/1) is situated in the right exhaust downpipe just prior to the mini-catalytic convertor. The left upstream sensor (1/1) is situated in the left exhaust downpipe just prior to the mini-catalytic convertor. The ideal downstream sensor (2/2) is located in the best exhaust downpipe just after the mini-catalytic convertor, and also before the key catalytic convertor. The left downstream sensor (1/2) is located in the left exhaust downpipe simply after the mini-catalytic convertor, and before the main catalytic convertor

02S Sensor removal

Never apply any form of grease come the oxygen sensor electrical connector, or attempt any soldering of the sensor wiring harness.

WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES and CATALYTIC CONVERTER(S) BECOME an extremely HOT during ENGINE OPERATION. Enable ENGINE come COOL before REMOVING OXYGEN SENSOR.

1. Raise and support vehicle.

2. Disconnect O2S pigtail harness from key wiring harness.

3. If equipped, disconnect sensor wire harness mounting clips from engine or body.

CAUTION: when disconnecting sensor electric connector, perform not pull directly on cable going right into sensor.

4. Remove O2S sensor through an oxygen sensor removal and installation tool.

02S Sensor installation

Threads of brand-new oxygen sensors are factory coated with anti-seize link to assist in removal. Perform NOT include any additional anti-seize compound to subject of a new oxygen sensor.

1. Install O2S sensor. Tighten come 22 ft. Lbs. (30 N·m) torque.

2. Affix O2S sensor cable connector to key wiring harness.

See more: Does The 2005 Honda Accord Ex Auxiliary Port, How To Install An Aux In A 2003‐2007 Honda Accord

3. If equipped, attach sensor cable harness mounting clips come engine or body. As soon as Equipped: The O2S pigtail harness have to be clipped and/or bolted earlier to their original positions on engine or human body to protect against mechanical damage to wiring.

Grand Cherokee WJ oxygen sensors

(Part Numbers: Black text = federal emissions, black + red text = California emissions)

EngineBefore catalystAfter catalyst

1999-2000

4.0L56041676AA(w/10.5″ pigtail)56041212AE(w/18″ pigtail)56041344AD(w/14″ pigtail)56041212AF(w/12″ pigtail)
4.7L56028233AA(w/12″ pigtail)56028232AA(w/18″ pigtail) 56041345AD(w/14″ pigtail)56028235AA(w/12″ pigtail)

2001-2003

4.0L56041943AA56041944AA56041845AB5139020AA
4.7L56029333AA56041941AA56041345AE56041731AA

2004

4.0L56028995AA56028994AA56028997AA05139021AA
4.7L56044580AA56044581AA56044582AA56044583AA