Welcome to the tennis2007.org comprehensive page on WJ Generation Jeep grand Cherokee oxygen sensors. We have organized as much information as we can find right into a helpful article below. Is something not correct or missing? Please get in touch with us and we’ll fix it!

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Grand Cherokee WJ oxygen sensor

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

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The O2 sensor must have a source of oxygen from exterior of the exhaust stream because that comparison. Existing O2 sensors obtain their fresh oxygen (outside air) supply through the O2 sensor instance housing.

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

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

The Oxygen Sensors (O2S) room attached to, and also protrude into the auto exhaust system. Depending upon the emissions package, the vehicle may use a full of either 2 or 4 sensors.

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

Two sensors space used: upstream (referred to together 1/1) and also downstream (referred to as 1/2). With this emission package, the upstream sensor (1/1) is situated just prior to the main catalytic convertor. The downstream sensor (1/2) is located just after the main catalytic convertor.

California Emissions package (4.0L engine):

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

California Emissions parcel (4.7L engine):

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

02S Sensor removal

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

WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES and CATALYTIC CONVERTER(S) BECOME an extremely HOT throughout ENGINE OPERATION. Allow ENGINE to COOL prior to REMOVING OXYGEN SENSOR.

1. Raise and also support vehicle.

2. Disconnect O2S pigtail harness from main wiring harness.

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

CAUTION: when disconnecting sensor electric connector, execute not pull straight on cable going into sensor.

4. Eliminate O2S sensor with an oxygen sensor removal and also installation tool.

02S Sensor installation

Threads of brand-new oxygen sensors are manufacturing facility coated v anti-seize compound to assist in removal. Perform NOT include any extr anti-seize compound to object of a brand-new oxygen sensor.

1. Download O2S sensor. Tighten to 22 ft. Lbs. (30 N·m) torque.

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

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3. If equipped, affix sensor wire harness mounting clips come engine or body. Once Equipped: The O2S pigtail harness have to be clipped and/or bolted earlier to their initial positions top top engine or body to prevent mechanical damage to wiring.

Grand Cherokee WJ oxygen sensors

(Part Numbers: Black message = federal emissions, black color + 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