Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSFORD2004PICKUP F350 SUPER DUTY, 4D PICKUP, 6.8 S, RWD, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - PINPOINT TEST DX: ENGINE COOLANT TEMPERATURE (ECT) SENSOR THROUGH PINPOINT TEST HC: FUEL DELIVERY SYSTEM - CNG, FLEX-FUEL & GASOLINEPINPOINT TEST H: FUEL CONTROLTEST PROCEDURE

2004 Ford Pickup F350 Super Duty, 4D Pickup, 6.8 S, RWD, Automatic

Test Procedure

2004 Ford Pickup F350 Super Duty, 4D Pickup, 6.8 S, RWD, AutomaticSECTION Test Procedure

H1 PERFORM THE KOER SELF-TEST

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION table of fault code setting condition.

FAULT CODE SETTING CONDITION

Fault Code

KOEO

KOER

Continuous Memory

P0040 1

H69

P0041 1

H69

P0053

H12

P0054

H12

P0055

H12

P0059

H12

P0060

H12

P0061

H12

P0131

P0132

H60

P0133

P0135 1

H10

P0136

H58

P0138

H60

P0141 1

H10

P0144

H60

P0147

H10

P0151

P0152

H70

P0153

P0155 1

H10

P0156

H58

P0158

H70

P0161 1

H10

P0167

H10

P0171 1

H17

P0172 1

H22

P0174 1

H17

P0175 1

H22

P0201 1

H41

P0202 1

H41

P0203 1

H41

P0204 1

H41

P0205 1

H41

P0206 1

H41

P0207 1

H41

P0208 1

H41

P0209 1

H41

P0210 1

H41

P0211 1

H41

P0212 1

H41

P1127 1

H68

P1128 1

H69

P1129 1

H69

P1130 1

H17

P1131 1

H17

P1132 1

H22

P1137

H58

P1138

H58

P1150 1

H17

P1151 1

H17

P1152 1

H22

P1157 1

H58

P2195 1

H17

P2196 1

H22

P2197 1

H17

P2198 1

H22

P2270

H58

P2271

H58

P2272

H58

P2273

H58

P2274

H58

P2275

H58

P2278 1

H69

⁽¹⁾

For Natural Gas Engines see FAULT CODE SETTING CONDITION

Engine at normal operating temperature.
Check for self-test DTCs.

Are DTCs P0040, P0041, P1127, P1128, P1129 or P2278 present?

Yes	No
Key in OFF position. DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS .	GO to H2.

H2 CONTINUOUS MEMORY DTCS P0133 AND P2190: HO2S RESPONSE TEST

Key ON, engine OFF.
Select 'Generic OBD II Function'.
Press CONTINUE.
Select 'Diagnostic Monitoring Test Results'.
Scroll to Test ID: 01.
Key in OFF position.

Is the indicated value greater than the minimum threshold?

Yes	No
Key in OFF position. CLEAR the DTCs. Carry out the HO2S monitor drive cycle. GO to H1.	GO to H3.

H3 CHECK FOR UNMETERED AIR LEAKS

NOTE: Fuel calculations can be affected by unmetered air leaks.

Carefully inspect the following areas for potential air leaks:
- Hoses connecting to the MAF sensor assembly.
- Hoses connecting to the throttle body.
- Intake manifold gasket leaks.
- PCV disconnected.
- The vacuum lines are disconnected.
- Improperly seated engine oil dipstick, tube or oil fill cap.
- Exhaust leaks at flanges and gaskets.

Are any air leaks present?

Yes	No
REPAIR the source of the air leak. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .	GO to H4.

H4 CHECK HO2S CIRCUIT CONTINUITY

HO2S connector disconnected.
Check the connector (both halves) for any water contamination.

Connect a 5 amp fused jumper wire between the following:

Point A HO2S Connector, Harness Side	Point B HO2S Connector, Harness Side
HO2S Signal	VPWR

Key ON, engine running.
NOTE: HO2S is displayed as O2S on the diagnostic tool.
Access the PCM and monitor the HO2S Signal PID.

Is the voltage greater than 1 V?

Yes	No
Key in OFF position. INSTALL a new HO2S. CHANGE the engine oil filter. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .	Key in OFF position. GO to H5.

H5 CHECK THE HO2S CIRCUIT(S) FOR AN OPEN IN THE HARNESS

Remove the jumper wire(s).
NOTE: A vehicle hoist may be required to access the HO2S harness.
Visually inspect the HO2S harness for exposed wiring, water contamination, corrosion, and proper assembly.
PCM connector disconnected.

Measure the resistance between:

( + ) PCM Connector, Harness Side	( - ) HO2S Connector, Harness Side
HO2S Signal	HO2S Signal
SIGRTN	SIGRTN

Are the resistances less than 5 ohms?

Yes	No
GO to H6.	REPAIR the open circuit. Carry out the HO2S monitor drive cycle.

H6 CHECK THE HO2S CIRCUIT FOR A SHORT TO VPWR IN THE HARNESS

Measure the resistance between:

( + ) PCM Connector, Harness Side	( - ) PCM Connector, Harness Side
HO2S Signal	VPWR

Is the resistance greater than 10K ohms?

Yes	No
GO to H7.	GO to H9.

H7 DTC P0131: CHECK FOR A SOURCE OF POTENTIAL HO2S CONTAMINATION

Investigate the following items as potential sources of HO2S contamination:
- Use of unapproved silicon sealers.
- Fuel contaminated by silicon additives.
- Excessive oil burning. (rings, valve seals, oil overfill).
- Glycol leaking internally in the engine.
- Lead-contaminated fuel.
- Short drive cycles in cold weather.
- Use of unapproved cleaning agents.

Were any of the above conditions or concerns found during inspection?

Yes	No
Repair the source of contamination. CHANGE the engine oil filter. RESET the keep alive memory (KAM). REFER to RESETTING THE KEEP ALIVE MEMORY (KAM) .	GO to H8.

H8 DETERMINE THE DTC BEING DIAGNOSED

Are you diagnosing DTC P0141 or P0161?

Yes	No
GO to H10.	GO to H9.

H9 VERIFY THE HARNESS PINS ARE IN THE PROPER LOCATION

Measure the resistance between:

( + ) PCM Connector, Harness Side	( - ) HO2S Connector, Harness Side
HO2S Signal	HO2S Signal
SIGRTN	SIGRTN

Are the resistances less than 5 ohms?

Yes	No
INSTALL a new HO2S.	REPAIR as necessary.

H10 DTCS P0135, P0141, P0147, P0155, P0161 OR P0167: VISUALLY INSPECT THE HO2S HARNESS

PCM connector connected.
Visually inspect the HO2S harness for exposed wiring, water contamination, corrosion, and proper assembly.

Were any exposed wiring, contamination, corrosion and correct assembly concerns present?

Yes	No
REPAIR as necessary.	GO to H11.

H11 PERFORM KOEO THE ON-DEMAND SELF-TEST

Key ON, engine OFF.

Are any of the following DTCs present: P0135, P0141, P0147, P0155, P0161 or P0167 .

Yes	No
Key in OFF position. GO to H12.	Key in OFF position. GO to H13.

H12 DTCS P0053, P0054, P0055, P0059, P0060 AND P0061: CHECK FOR VPWR IN THE HARNESS

NOTE: If DTCs are present, test their related circuits individually.

HO2S connector disconnected.
Key ON, engine OFF.
Measure the voltage between:

( + ) HO2S Connector, Harness Side	( - ) HO2S Connector, Harness Side
VPWR	SIGRTN

Is the voltage greater than 10.5 V?

Yes	No
Key in OFF position GO to H13.	REPAIR the open circuit. Check fuses.

H13 CHECK THE HO2S HEATER FOR SHORTS IN THE HARNESS

HO2S connector disconnected.
PCM connector disconnected.
NOTE: If DTCs P0053, P0054, P0055, P0059, P0060 or P0061 are present, test their related circuits individually.

Measure the resistance between:

( + ) HO2S Connector, Harness Side	( - ) Vehicle Battery
HO2S Heater	Negative terminal

Measure the resistance between:

( + ) HO2S Connector, Harness Side	( - ) HO2S Connector, Harness Side
HO2S Heater	VPWR
HO2S Heater	SIGRTN
HO2S Heater	HO2S Signal

Are the resistances greater than 10K ohms?

Yes	No
GO to H14.	REPAIR the short circuit.

H14 CHECK THE HO2S CIRCUIT FOR AN OPEN IN THE HARNESS

Measure the resistance between:

( + ) PCM Connector, Harness Side	( - ) HO2S Connector, Harness Side
HO2S Heater	HO2S Heater

Is the resistance less than 5 ohms?

Yes	No
GO to H15.	REPAIR the open circuit.

H15 CHECK THE INTERNAL RESISTANCE OF HO2SHTR

Measure the resistance between:

( + ) HO2S Connector, Component Side	( - ) HO2S Connector, Component Side
HO2S Heater	VPWR

Is the resistance between 3 ohms - 30 ohms?

Yes	No
GO to H16.	INSTALL a new HO2S.

H16 CHECK THE HO2S CASE FOR A SHORT TO VPWR, HTR AND SIGRTN

Measure the resistance between:

( + ) HO2S Connector, Component Side	( - ) HO2S Connector, Component Side
HO2S Heater	SIGRTN

Measure the resistance between:

( + ) HO2S Connector, Component Side	( - ) Vehicle Battery
HO2S Heater	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
INSTALL a new PCM.	INSTALL a new HO2S.

H17 DTCS P0171, P0174, P1130, P1131, P1150, P1151, P2195 OR P2197: LEAN SYSTEM DTCS

NOTE: Do not clear the DTCs or reset the keep alive memory (KAM).

Access the PCM and record the ECT PID from the freeze frame data. The freeze frame data is used to recreate the concern.
Retrieve and record the self-test DTCs.

Are any DTCs present other than the following: P0171, P0174, P1130, P1131, P1150, P1151, P2195 or P2197?

Yes	No
DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS .	GO to H18.

H18 CARRY OUT A VISUAL INSPECTION ON THE INTAKE AIR SYSTEM AND ALL VACUUM HOSES

Check the intake air system for leaks, obstructions, and damage.
Inspect the entire length of all the vacuum hoses for:
- proper connections.
- damage or cracks.
- damaged or cracked vacuum tees.
Verify the integrity of the positive crankcase ventilation (PCV) system.
Verify the proper PCV valve part number.

Is a concern present?

Yes	No
GO to H21.	GO to H19.

H19 CHECK FOR THE PRESENCE OF A VACUUM LEAK
NOTE: Fuel trim values at idle are more sensitive to a vacuum leak. The vacuum leak (unmetered air) represents a larger portion of the total air flow at idle than at part throttle.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.