Where is the h20 sensor in bank one located on 1998 ford expedition 5.4

the h2o sensor may not be the only problem, some thing else is setting off the sensor, a pin hole in the hose, a loose connection, cracked lines, plug lines, blockage of sensor that controls the h2o unit, look at the whole picture, housing, gasket is that area, too much h2o, not enough h2o, gases mixtures + h20's, make sure you have the air pressures sucking and pushing through the line.
you are going to have to a service manual and general information how the h20 system works in that vehicle. test points.

www.ask.com/year/mfg.name/make/model/how/does/H20/system/works/on/vehicle/

Probably is the Oxygen sensors are bad seems i had same problem a few years back and had to replace the sensor. Hope this helps

It's going to be the one on the left (drivers) side (picture below). Through experience I have found that due to the location of these sensors the connectors get oil in them and moisture. Sometimes just cleaning the connector clears up any diagnostic trouble codes or drivabilty problems. Hope this helps you....

refers to o2 sensor bank 1 s1 is reading lean check for exh leak vaccume leak egr intake check for misfire


let me know if this helps comment reply if you need more info

depends... there are 2 sensors on each bank... bank 1 is the passenger side, sensor 1 is closest to the front of the vehicle( usually before the catalytic coverter) and sensor 2 is closest to the rear of the vehicle( after the cat. known as the cat monitor) hope this helps

for 1998 Ford Truck Expedition 4WD 5.4L EFI 8cyl the Oxygen Sensor is located under vehicle, driver side, below seating area, mounted in exhaust pipe in rear of catalytic converter.

Application: Number three

Hope helps (remember rated this).

1998 Ford Truck Windstar 3.8L SFI 6cyl, there are 4 oxygen sensors on the Windstars They are divided into 2 banks of 2. Bank 1 is the for the rear 3 cylinders of the engine - Bank 2 is for the front 3 cylinders. Bank 1 / Sensor 1 (upstream) is located just below, in the pipe, the exhaust manifold on the back of the engine.

REMOVE TIP: you may have to bend part of the transmission heat shield out of the way - be sure to put it back when done.
Bank 1 Sensor 2 (downstream) is located just past the drivers side catalytic converter.
Bank 2 Sensor 1 (upstream) is located just below the exhaust manifold, in the pipe, at the front of the van - access is from the top.
Bank 2 Sensor 2 (downstream) sensor is located just past the passenger side catalytic converter.

NOTES: * Use lots of penetrating oil - allow to soak - to make removal easier and avoid damaging the exhaust pipe

Hope this help; TY for using Fixya (remember rated and comment this).

CODE PO171 -SYSTEM ADAPTIVE FUEL TOO LEAN. POSSIBLE CAUSE.AIR LEAKS AFTER THE MAF SENSOR OR LEAKS IN THE PVC SYSTEM. EXHAUST LEAKS BEFORE OR NEAR WHERE THE HO2S IS MOUNTED. FUEL INJECTORS RESTRICTED OR NOT SUPPLYING ENOUGH FUEL. FUEL PUMP WEAK. LEAKING EGR VALVE GASKET OR DIAPHRAGM.MAF SENSOR DIRTY CAUSES PCM TO UNDERESTIMATE AIR FLOW / NOW THE BANK 1 SENSOR ITS MOUNTED IN THE EXHAUST SYSTEM BEFORE THE CATALYTIC CONVERTER.THE BANK 2 SENSOR IS IN EXHAUST AFTER THE CATALYTIC CONVERTER.

Assuming you are talking about the O2 sensors - they are both located in the exhaust system.

Bank1 is Under hood, driver side, lower engine area, below exhaust manifold flange, mounted in exhaust pipe.

Bank2 is by Cat.

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