My 2003 expedition 5.4 read a code P0354 i change spark plug, ignition coil, fuel injector and a computer and still read the p0354 code.

codes are OBDll and are available on line free. Every scan tool comes with booklet with codes in it. If the person scanning does not have booklet do not waste your time.

A P0354 code means that the ignition coil or coils are not functioning properly and that there is an electrical problem with them. The ignition coils are responsible for properly igniting the air-fuel mixture in the engine's combustion chambers.

OBD-II Code P0455 is defined as a Evaporative System Malfunction, Gross Leak

No one can diagnose your car without having it.

https://www.yourmechanic.com/article/p0354-obd-ii-trouble-code-ignition-coil-d-primary-secondary-circuit-malfunction-by-valerie-johnston

https://www.obd-codes.com/p0455

https://repairpal.com/obd-ii-code-chart

https://www.obd-codes.com/trouble_codes/

codes are OBDll and are available online free
try googling your code.

A P0354 code means that the ignition coil or coils are not functioning properly and that there is an electrical problem with them. The ignition coils are responsible for properly igniting the air-fuel mixture in the engine's combustion chambers. If a vehicle has a P0354 code stored, it will not be able to ignite that mixture with the correct timing, and the engine will run roughly and/or stall.

p0351,p0352,p0353 and p0354. It won't start because you have four cylinders not firing . P0351 - Ignition Coil A Primary/Secondary Circuit Description: See the description for DTC P0350. Possible Causes: See the possible causes for DTC P0350. Diagnostic Aids: See the diagnostic aids for DTC P0350. Application Key On Engine Off Key On Engine Running Continuous Memory Coil-on-plug (COP) ignition testing - GO to Pinpoint Test JF . GO to Pinpoint Test JF . Coil pack ignition testing - GO to Pinpoint Test JE . GO to Pinpoint Test JE .
When you see these codes , it's time to worry . These ford coil on plug system's can fry the transistors that control the coil firing . New computer or reman at ford $ 800.00 buck's then it needs to be programmed (dealer) What engine ? 3.0 v-6
This happens when the spark plug's are neglected , gap get's to wide , make's coil's over heat an break down , spark goes through the primary wire to the computer . Your best bet , take it to a qualified repair shop.

It may run fine but it's in fail safe mode
DTC P0351-P0354
DTCs P0351 through P0354 Ignition Coil Primary/Secondary Feedback Circuit diagnostic monitors the primary circuitry of individual ignition coils for the successful completion of an ignition event. The ignition trigger signal and ignition fail-safe input signal provide crucial information in the control of ignition system timing and the activation of the fail-safe function. Based on the initial timing angle, calculated from the crankshaft and the camshaft position signals, the powertrain control module (PCM) calculates the ignition trigger signal. The ignition trigger signal is then sent to the ignition control circuitry located in each ignition coil. The ignition control circuitry initiates the ignition dwell period by commanding the power transistor ON. When the PCM determines the proper time to provide spark, the PCM turns OFF the ignition trigger signal. In response to the PCM signal, the ignition coil control circuitry turns OFF the power transistor, producing a high voltage discharge from the secondary coil windings. After the spark has occurred, the control circuitry sends an ignition fail-safe input signal back to the PCM, confirming that an ignition event has taken place. If the ignition fail-safe input signal is not received by the PCM, a cylinder specific DTC will set.
Anytime the fail-safe input signal is lost, engine operation will enter the fail-safe function. If engine load exceeds certain parameters during the fail-safe function, Fuel Cut-off mode is activated and fuel injector operation is ceased. The suspension of fuel injection in the Fuel Cut-off mode protects the catalytic converter from damage. Damage can occur when excess unburned fuel reaches the converter and causes the catalyst to overheat.

Diagnostic Aids
• Check for the following conditions:
- An interruption of the ground circuit or voltage supply to the ignition coil will prevent a proper ignition event from taking place. A DTC P0351 through P0354 will set if there is a fault in any of the ignition coil circuits.
- If DTCs P0352, P0353, and P0354 are present, the fault is located in the shared electrical circuits or shared components of the ignition coils.
- Inspect the ignition coil grounds at G 105 for a clean and tight connection.
- The scan tool data parameters for Misfire Current Cylinder # are frozen at the time the MIL illuminates when the DTC sets.
- If no engine misfire is felt when the DTC sets, inspect for a fault in the Ignition Fail-Safe Input circuit.
- Inspect the noise filter for an internal short or low resistance. The ignition coil may not receive adequate voltage during high load conditions if the noise filter is faulty. A good noise filter will indicate infinite resistance (OL) with a DMM after the capacitor inside the filter is charged up.
- Unless the ignition key is cycled or the DTCs are cleared, the PCM waits to receive ignition fail-safe signals before providing fuel injector operation.
• An intermittent malfunction may be caused by a fault in the ignition coil electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions .
• Repair any electrical circuit faults that were found. Refer to Wiring Repairs .
• The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

code p0354 refers to ignition coil D, primary/secondary--circuit malfunction===causes--wiring--ignition coil--ECM
check that the connection to the coil is clean,dry and tight
replace the coil D

P0300 - Random multiple cylinder misfire
P0301 , 302 and 304 - Cyliners 1, 2 and 4 misfire
P0351 - Ignition coil A primary/secondary circuit malfunction
P0354 - Ignition coil D primary/secondary circuit malfunction

P0354 = Ignition Coil "D" circuit
P0356 = Ignition Coil "F" circuit

Inspect spark plugs first.

Then, measure/test your HT leads to ensure they are within spec.

If the above proves ok, then suspect a bad coil pack.

P0354 = Ignition Coil "D" circuit
P0356 = Ignition Coil "F" circuit

Inspect spark plugs first.

Then, measure/test your HT leads to ensure they are within spec.

If the above proves ok, then suspect a bad coil pack




Cheers,

Scott

clean the MAF, Mas Air Flow Sensor in the air intake tube first. Use carb cleaner or MAF cleaner. Do not touch the 2 sensor wires that you spray. delicate!!

ALso, put a bottle of Chevron Techron Fuel injector cleaner in the fuel tank, 1/4 tank or less.

Try that first. Also, replace spark plugs, put antiseize on the threads. Last resort is to replace the COPS, Coil on plug for each offending cylinder.

Misfire Definition: A misfiring cylinder is lacking power relative to the other cylinders. The causes for a cylinder specific misfire could be fuel, spark, or mechanical problems. Perform a thorough visual inspection. If no visible concerns are found use the following WDS tools for misfire diagnosis:

• Self-test (Check for codes first)
• Power Balance (Identify the cylinder of concern)
• Relative Compression (Rule out a possible mechanical issue)
• Fuel (Make sure fuel injectors are not restricted) (plugged)
• Ignition (Make sure spark plugs and coils are working properly)
• Oscilloscope (Detailed signal analysis)

P0354 Ignition Coil D Primary/Secondary Circuit

The wiring may be bad to the cylinder, but changing the coil position and getting same code means that the coil itself is not bad.