How to replace the O2 Sensors in a 1997 - 2003 F-150

An oxygen or O2 sensor steps oxygen levels in the exhaust stream and the PCM uses this info to change and keep a appropriate air-to-fuel ratio. One O2 sensor is taken into consideration a ingredient of the emissions regulate system, together the air-fuel proportion plays a crucial road in carbon and NOx emissions.

Applicable design Years: 1997 - 2003 Ford F-150 (general measures applicable to more recent models) 1997 - 2003 downstream O2 sensor (rear): Motorcraft DY1093 (Ford F85Z-9G444-BA) 1997 - 1998 upstream O2 sensor (front): Motorcraft DY832 (Ford F88F-9F472-AB) 1999 upstream O2 sensor (front): Motorcraft DY1093 (Ford F85Z-9G444-BA) 2000 - 2003 upstream O2 sensor (front): Motorcraft DY835 (Ford XL3F-9F472-AA)

When an O2 sensor stops working or generates an erratic/out-of-range signal, the PCM will certainly resort to making use of a predetermined, conservative estimate in place of the actual time reading. This deserve to yield lower performance, fuel economy, and also throttle response. As soon as a sensor fail is detected, a diagnostic trouble code (DTC) and also check engine light are typically set identifying the faulty O2 sensor. When it"s perfect acceptable to just replace the sensor(s) that have triggered a DTC (DTCs will vary, but generally decide the bank and upstream/downstream position), we"ve constantly replaced the O2 sensors in sets come ensure the selection of readings is equal between sensors.

There space (4) O2 sensors top top a 1997 - 2003 Ford F-150; two prior to the very first catalytic converters top top each financial institution of the engine and two inside each that the behind catalytic converters ~ above each financial institution of the engine (see map below). The O2 sensors closest come the engine are referred to as "upstream" sensors, while the rearmost are referred to as "downstream" sensors. There is a difference between upstream and also downstream sensors, therefore mind the correct component number(s) for your vehicle.

For each sensor, you"ll must 1) disconnect the electric connector top top the sensor pigtail, 2) eliminate the old sensor, 3) download the brand-new connector utilizing a liberal lot of anti-seize link on the threads, and also 4) reconnect the electrical connector. It is not uncommon for the subject in a sensor bung to piece - details ~ above repairing the threads have the right to be uncovered below.

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• The photo at left provides you a general idea of the ar of the O2 sensors. Every O2 sensor has actually a 22 mm nut at its base, however they will additionally accept a 7/8" tool. O2 sensor sockets are typically compatible through both 7/8" and 22 mm sizes. The hex head at the basic of the sensor is very easy to round off through an open finish wrench or crowfoot. That is extremely advised the only O2 sensor sockets or a flare nut wrench/crowfoot is provided to remove and also install the sensors. To make matters worse, you can expect the sensors to be incredibly tight in your bungs. You might need to access a range of tools in order come reach all the sensors - carry out not mean to with them all with a straightforward wrench.


• Disconnect the an unfavorable battery cable.

• introduce to the photo at left, there room a variety of 22 mm, 7/8" sockets and also tools available to eliminate O2 sensors in confined spacers - a selection of these devices were forced to remove and also install the 4 sensors. Part sensor areas have higher spacial constraints 보다 others.


Driver next front sensor - The front sensor ~ above the driver side is reasonably simple to eliminate with a 22 mm flare nut wrench. The is accessed from in ~ the truck.


Driver side rear sensor - since this van is 4 wheel drive, the transfer situation limits access to the behind catalytic converter, which is whereby the O2 sensor is located. Loosening the exhaust clamp situated behind the catalytic converter and also unbolting the exhaust collector that connects the exhaust system to the exhaust manifold permitted us to lower a 2-3 foot section of the exhaust mechanism that includes the two catalytic converters. This provided us just enough room to accessibility the sensor, remove it with a 22 mm flare nut wrench, install the brand-new sensor, and also slide the exhaust ago into place. This might not be forced for every applications, yet it do the task much much easier in this case.


Passenger side front sensor - The passenger next front O2 sensor is located directly behind the exhaust collector wherein the exhaust manifold connects to the exhaust system. This truck has actually the sensor pointing upwards, however some van will have actually the sensor pointing inward. Removed of the within fender (plastic liner within the front fender) and the infection dipstick tube may be required. Us were may be to remove this sensor by unfastening half of the inner fender and also pulling it out of the way. This is usually the most time spend sensor come remove due to its location, so be ready to usage all the tools in your arsenal.

Passenger side behind sensor - Accessing this sensor is comparable to accessing the driver side rear, however without having actually to disconnect the exhaust system. You may select to remove the catalytic converter warm shield, but we did not have to.

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O2 Sensor Bung subject Repair

If the threads of the O2 sensor bung end up being damaged and the new sensor will not thread right into place, you"ll have to chase the threads v a tap. The is relatively common because that the object to come to be damaged ~ removing a stubborn sensor - these space subjected to countless heating and cooling cycles end the course of their life and also tend to end up being stuck.

The threads room M18 x 1.5 and a one-of-a-kind tap is easily accessible that is designed come fit right into tight locations. One instance is Lisle 12230 (see connect for details). A regular tap is daunting to usage as it will not fit in most situations due come spacial limitations. The committed tool is much much shorter and works with a socket/wrench rather of a standard tap handle.

Chase the threads utilizing a liberal quantity of cutting liquid (or even motor oil) ~ above the cutting this of the tap. Be sure to clean the threads by frequently backing the tap the end a complete turn because that every 1 come 2 cutting rotations. As soon as the threads have been repaired, clean the area thoroughly and wipe any oil indigenous the exhaust tubing v a rag and also a solvent (brake cleaner, carbohydrate cleaner, etc). is not affiliated v nor endorsed by Ford Motor agency or any manufacturer pointed out herein, uneven explicitly listed otherwise.