20 Most Recent 1998 Ford Expedition - Page 5 Questions & Answers

Here's a link to code P0156. P0156 O2 Sensor Circuit Malfunction Here's a link to code.P0174. http://www.obd-codes.com/p0174

For a Ford, you either have to look in your owners manual, or hope to find the information you need by Googling it. They weren't smart enough to label what is what on the cover like Chevrolet and Chrysler.

Along the fuel rail. It believe that it is on the drivers side.

In the fuse / relay box in the engine compartment !

Check the throttle position sensor.

You need to replace the transmission you just put in. Sorry. It is not worth your money to start throwing new parts on a transmission that is potentially junk. First you have to start with a TCC solenoid, then the valve body, then the torque converter. Then when you spend all the money and time on this. You still have a junk transmission.

Not exactly. It will take a few minutes of cranking to push the air out of the line, but thats it. If you don't have fuel at the injectors after one or two minutes of cranking, you may have another problem.

Drop the fuel tank and remove the tank sending unit.

Normally this condition is the result of a poor body ground connection. Testing for this can be deceiving. At the static(nothing on) condition, testing can show a good ground. However when a circuit is excited, it has a determined resistance and a set current flow. If the ground connection to this or a branch circuit is loose, corroded, or broken wire. This will allow just enough connection to show as being good, but not good enough to complete the circuit with the required amount of connection when energized.

start here

The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving condition:

• Ride is improved by using an air type spring (the soft ride is inherent).
• Handling is improved by maintaining constant vehicle attitude.

The system consists of unique rear air springs, air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) transfer case inputs, and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines, and the use of an air spring with an air spring solenoid.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed and the vehicle speed exceeds 16 km/h (10 mph).
Air Suspension Switch
The air suspension switch is located behind the RH kick panel on a mounting bracket. The switch interrupts power to the air suspension control module.
The air suspension switch supplies a signal to the air suspension control module. Without the air suspension control module receiving this signal the load leveling system is inoperative and will not react when rear of the vehicle is raised or lowered. If the air suspension system is disabled by turning off air suspension switch, a "CHECK SUSP" will appear in the RH corner of the instrument cluster with the ignition in the run position.
Air Compressor
The RAS air compressor:

• Is not interchangeable with four wheel air suspension (4WAS) compressor.
• Consists of the compressor and vent solenoid; neither are replaceable as individual items.
• Is mounted in the engine compartment between the washer fluid bottle and headlamp (RH front corner).
• Is a single cylinder electric motor driven unit that provides pressurized air as required.
• Is powered by a solid state relay, controlled by the air suspension control module.
• Passes pressurized air through the compressor air drier that contains silica gel (a drying agent). Moisture is then removed from the compressor air drier when vented air passes out of the system during vent operation.
• Air drier has a single port and is not interchangeable with 4WAS compressor air drier.
• Air drier may be replaced separately.
• Incorporates a snorkle that may be replaced separately.

The vent solenoid:

• Allows air to escape from the system during venting actions.
• Is located in the air compressor cylinder head.
• Has a 160 psi internal relief valve.
• Shares a common electrical connector with the air compressor motor.
• Is enclosed in the cylinder head casting, which forms an integral valve housing that allows the valve tip to enter the pressurized side of the system.
• Has an O-ring seal that prevents air leakage past the valve tip.
• Opens when the air suspension control module determines lowering is required.
• Provides an escape route for pressurized air that opens when system pressures exceed safe operating levels.
• Is replaced with the air compressor as a unit.

Air Spring
RAS vehicles use air springs in the rear. The air springs provide a varying spring rate proportional to the systems air pressure and volume. The air suspension system regulates the air pressure in each air spring by compressing and venting the system air. Increasing air pressure (compressing) raises the rear of the vehicle while decreasing air pressure (venting) lowers the rear of the vehicle. Vehicle height is maintained by the addition and removal of air in each air spring through an air spring solenoid installed in the upper spring cap and energized through the air suspension control module.
The air springs are mounted between the axle spring seats and the frame upper spring seats.
The two air springs replace the conventional rear coil springs.
Air Suspension Height Sensor
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level.
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket). Replace the air suspension height sensor as a unit.
Compressor Relay
The compressor relay is energized by the air suspension control module to allow high current to flow from the battery to the compressor motor.

• A solid state relay is used in the air suspension system for air compressor control. The relay incorporates a custom power metal oxide semi-conductor field effect transistor (MOSFET) and ceramic hybrid circuitry. The relay switches high current loads in response to low power signals and is controlled by the logic of the air suspension control module.

Air Suspension Control Module
NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS equipped vehicle.
NOTE: The air suspension control module is calibrated with information from the air suspension height sensor. A new or exchanged air suspension control module requires a ride height adjustment calibration process to be performed.
The air suspension control module controls the air compressor motor (through a solid state relay), and the air spring solenoids. The air suspension control module also provides power to the air suspension height sensor. The air suspension control module controls vehicle height adjustments by monitoring the air suspension height sensor, vehicle speed, a steering sensor, acceleration input, the door ajar signal, transfer case signals, and the brake pedal position (BPP) switch. The air suspension control module also conducts all fail-safe and diagnostic strategies and contains self-test and communication software for testing of the vehicle and related components.
The air suspension control module is mounted in the passenger compartment inside the instrument panel above the radio and temperature controls.
The air suspension control module monitors and controls the air suspension system through a 32-pin two-way connector. The air suspension control module is keyed so that the air suspension control module cannot be plugged into an incorrect harness. There are two sides of the harness connection to the air suspension control module. Each is uniquely colored and keyed to prevent reversing the connections.
Air Suspension Diagnostic Connector
The air suspension diagnostic connector is used to aid the technician in diagnosing the air suspension system. It is also used to vent the system of compressed air when air suspension system components need to be repaired or replaced. The air suspension diagnostic connector is located under steering column.

Check to see if your speaker wires are cut from the radio to the speakers. Not all of the speakers will stop working at the same time. On my 2001 expedition, the front worked but not the doors or rear. I found a cut speaker wire that is located behind the windshield trim above the stearing wheel where someone had installed an air freshener with a screw

As a vehicle ages, the timing gets off, and the Octane of fuel will compensate for an out of timing vehicle. Bad gas is main culprit, also dirty/clogged fuel filter, or clogged carberetor or injectors! Use a "GOOD" fuel system cleaner for the next 3 tankfuls, and use a higher octane fuel at the same time!!! This is important. After 3 tankfuls and 3 additions of a Fuel System Cleaner, go back to a lower octane fuel. Drive up a hill and see if the problem is gone. If not, then either take it to a mechanic and check timing, hopefully you replaced the fuel filter by then.

Try slapping your hand on the dash above the instrument cluster a couple of times to see if it comes back. If not, there may be a fuse that you have overlooked

push the clock button with the radio off and key on,then hit the fast forward and rewind to adjust the time

If you have oil in your coolant res. Its not a good sign. This means you have a blown head gasket. The part is quite cheap compared to the labour involved in taking the top of the motor apart. I would try flushing the coolant and with the new coolant add a bottle of head gasket repair. There are several different kinds, some are even industrial grade. It has saved me a couple times from huge mechanic bills. If this doesnt work then u may need to replace that gasket.

Hi do you have a metal key if so unlock the door with it this should disable the alarm. If not find an auto lock Technition of go to local ford dealer.

you will have to take the vehicle and the key to a service dealer and have then both programmed together.

It will need to be replaced, or if it is a gasket, just replace the gasket.

Sounds like it could be a weak fuel pump.Check your fuel pressure it should be 30-45 psi.

Personally I would go to junk yard and get that part you described. That part is rather easy to get to and replace. Good luck