Code 41 and 91

[hotcobra03]

fuel control steps by ford

following what tests you have done already,,o2 test,fuel pressure,cbt test,pulled vacuum hose and sucked fuel in to intake,,,I HAVE A QUESTION ON THE CBT TEST,,,, going by fords book,,H1 ck fuel pressure..you passed,,goto H2ck systems ability to hold pressure,,you failed,,gotoH9cbt test,,is code 90 present,,you passed,,goto h10PERFORM 2nd/3rd level cbt test....HAVE YOU DONE THAT YET?

 

[Haus]

no cause i have no idea what H1 H2 ect. mean

 

[Haus]

but i turned off my car and went to start is back up and it just has 1 click from the starter solenoid area and wont start. haha if it isnt one thing, it's another

i turned on the key and tried to jump the car with the 2 things on the starter Solenoid and pulled out the thing on that little screw but nothing clicked and only got sparks got sparks. weirds. i was just driving. turned off my car and went to start it back up and othing but 1 click at the soleniod

 

[faslane]

I have been watching your thread all week, I am having the same issues as far as code 41&91. I have a thread on the corral. I have been searching tonight, and found coming out of the wire harness under the passanger side hood hindge, that wire sticking out is a fusible link for the heater wire for the O2s, if that link is blown the O2s will stick on lean code 41&91,
Mabye this will help.
You can check it after you put you new starter on,
Lane

 

[Haus]

i think its a fuel pressure problem.

 

[hotcobra03]

pinpoint test

haus,code 41/91 are ego lean ..ford sells thier manual which tells you what it is and how to test for the problem,,,yours is fuel control H is the section in book and h1 is step 1-h2 step 2...in the beginning of fuel test it gives a list of things that can cause 41/91 thats non eec related(pcm codes ) what i have for your car is on paper..i can post on newer version but it might not help you...ill post it anyway you can read it maybe something jumps out at u...here is the list of non eec items...ign coil,dist cap,rotor,spark plugs,spark plug wires,canp,egr valve and gasket,air filter,fuel contamination,(engine oil),poor power ground,fuel pressure,manifold leaks (intake/exhaust),engine not at normal operating temperatures,,and the only one with a footnote PCV valve..the pintest will check hego sensor,hego signal and ground circuit,hego connection,vacuum system,fuel injector,processor assembly,harness circuits-HEGO GRD,HEGO,INJ1-8 and VPWR

 

[hotcobra03]

pinpoint test

haus,code 41/91 are hego lean ..ford sells thier manual which tells you what it is and how to test for the problem,,,yours is fuel control H is the section in book and h1 is step 1-h2 step 2...in the beginning of fuel test it gives a list of things that can cause 41/91 thats non eec related(pcm codes ) what i have for your car is on paper..i can post on newer version but it might not help you...ill post it anyway you can read it maybe something jumps out at u...here is the list of non eec items...ign coil,dist cap,rotor,spark plugs,spark plug wires,canp,egr valve and gasket,air filter,fuel contamination,(engine oil),poor power ground,fuel pressure,manifold leaks (intake/exhaust),engine not at normal operating temperatures,,and the only one with a footnote PCV valve..the pintest will check hego sensor,hego signal and ground circuit,hego connection,vacuum system,fuel injector,processor assembly,harness circuits-HEGO GRD,HEGO,INJ1-8 and VPWR

 

[hotcobra03]

fuel control

po171/174 are lean codes,,,and h41 is where these codes sent you if you were obd2,i didnt see cbt test in here cause this is obd2 tests...most of what you need is really in here2003 PCED OBD SECTION 5: Pinpoint Tests
Procedure revision date: 07/01/2003

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H: Fuel Control H: Introduction

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H41 DTCs P0171, P0172, P0174 AND P0175: FUEL SYSTEM AT THE CORRECTED FUEL TRIM
Note: It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any Fuel Trim DTCs.

Fuel System DTC Reference List:

Bank 1 = DTCs P0171 (lean) and P0172 (rich)
Bank 2 = DTCs P0174 (lean) and P0175 (rich)
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check fuel delivery system and filter for restriction.
Check for vacuum leaks.
Were any concerns found during inspection?
Yes No
REPAIR as necessary. COMPLETE KAM Reset. GO to DC25 .

H42 PERFORM KOER SELF-TEST
Disconnect fuel vapor hose from intake manifold and plug fitting at intake manifold.
Start engine and run at 2000 rpm for 5 minutes and return to idle.
Complete Key On Engine Running (KOER) Self-Test.
Are any HO2S DTCs P0040, P0041, P1127, P1128, P1129, P1131, P1132, P1151, P1152, P2195, P2196, P2197 or P2198 present?
Yes No
KEY OFF. If DTC P0040, P0041, P1127, P1128 or P1129 is present, GO to Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts and REPAIR those DTCs first.

DTCs (P1131, P2195) or (P1151, P2197):

GO to H43 .

DTCs (P1132, P2196) or (P1152, P2198):

GO to H49 . KEY OFF. For Continuous Memory DTCs Only P0171, P0174, P0172 and P0175:

GO to H52 .

If DTC(s) P1132, P2196and/or P1152, P2198 are no longer present, RECONNECT fuel vapor line.

Vehicles experiencing KOER DTC P1131, P1132, P1151, P1152, P2195, P2196, P2197 or P2198: REFER to Evaporative Emissions, Section 303-13 in the Workshop Manual for system leakage.

All others without recurring DTCs:

Unable to duplicate or identify fault at this time. GO to Z1 .

H43 HO2S CIRCUIT TEST (WITH LEAN DTCs)
Disconnect the HO2S related to the DTC.
Key on, engine off.
Access the correct HO2S PID.
Note: If arcing occurs (indicating a short), remove jumper and GO to H47 (check fuse in the heater circuit).

Jumper the HO2S SIG circuit to the VPWR circuit at the HO2S vehicle harness connector.
Note: If viewing the HO2S11 (O2S11) PID on the 2.3L Focus, the engine must be running.

Is the reading 1.30 volts or greater?
Yes No
KEY OFF. CHECK SIG RTN circuit. GO to H44 . KEY OFF. GO to H46 .

H44 CHECK SIGNAL RETURN CIRCUIT FOR OPEN
Measure resistance of HO2S SIG RTN circuit between the HO2S harness connector and the battery negative post.
Is the resistance reading less than 5.0 ohms?
Yes No
Reconnect HO2S, GO to H52 . GO to H45 .

H45 CHECK HO2S SIGNAL RETURN CIRCUIT FOR OPEN IN HARNESS
Disconnect PCM.
Measure resistance of HO2S SIG RTN circuit between the PCM harness connector pin and HO2S harness connector.
Is the resistance reading less than 5.0 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPAIR open circuit.

H46 CHECK HO2S SIGNAL AND HO2S GND CIRCUITS FOR OPEN IN HARNESS
Disconnect PCM.
Measure resistance of HO2S SIG circuit between PCM harness connector pin and the HO2S harness connector.
Is the resistance reading less than 5.0 ohms?
Yes No
GO to H47 . REPAIR open circuit.

H47 CHECK HO2S CIRCUIT FOR SHORT TO GROUND IN HARNESS
Disconnect PCM.
Measure resistance between the HO2S SIG and PWR GND circuits; and the HO2S SIG and SIG RTN circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
GO to H48 . REPAIR short circuit.

H48 CHECK HO2S CIRCUIT FOR SHORT TO GROUND
Disconnect PCM.
Reconnect HO2S.
Measure resistance between HO2S SIG and PWR GND circuits and HO2S SIG and SIG RTN circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPLACE HO2S.

H49 HO2S CIRCUIT CHECK (FOR RICH DTCS)
Disconnect the HO2S related to the DTC received.
Key on.
Access the correct HO2S PID(s).
Note: If viewing the HO2S11 (O2S11) PID on the 2.3L Focus, the engine must be running.

Is the reading 0.2 volt or less?
Yes No
KEY OFF. GO to H51 . KEY OFF. GO to H50 .

H50 CHECK HO2S CIRCUIT FOR SHORT TO VPWR AND HO2S HEATER GROUND IN HARNESS
Disconnect PCM.
Measure resistance between the HO2S SIG and VPWR circuits; and HO2S Signal and HO2S HTR circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPAIR short circuit.

H51 CHECK HO2S SIGNAL FOR SHORT TO HO2S HEATER CIRCUIT IN THE SENSOR
Suspect HO2S sensor disconnected.
Measure resistance between the HO2S SIG and HO2S HTR circuits at the HO2S connector.
Is the resistance greater than 10,000 ohms?
Yes No
KEY OFF. GO to H52 . KEY OFF. REPLACE HO2S.

H52 CHECK FUEL PRESSURE
WARNING: THE FUEL SYSTEM IS PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHEN WORKING ON THE FUEL SYSTEM. BECOME FAMILIAR WITH THE WARNING CAUTION AND NOTE IN PINPOINT TEST HC BEFORE SERVICING.

Connect battery charger.
Install fuel pressure gauge.
Key on, engine off.
Access Output Test Mode and run the fuel pump to obtain maximum fuel pressure.
NOTE: The fuel pump will only operate for approximately 8 seconds when Output Test Mode is selected and activated. (GO to Pinpoint Test HC to refer to the Fuel Delivery System Test Information Chart.)
Is the fuel pressure within range for the vehicle being diagnosed?
Yes No
KEY OFF.

GO to H53 . KEY OFF. GO to HC1 .

H53 CHECK FUEL SYSTEM FOR PRESSURE STABILITY — FAST LEAKDOWN
Cycle key on and off several times.
Key on and engine off, monitor fuel pressure gauge.
Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after 10 seconds?
Yes No
GO to H54 . Check fuel system for external leaks.

If external leak is detected, GO to HC1

If no external leak is detected, GO to H55

H54 CHECK FUEL SYSTEM FOR PRESSURE STABILITY WITH KEY ON — SLOW LEAKDOWN
Cycle key on and off several times.
Key on and engine off, monitor fuel pressure gauge.
Does the fuel pressure remain within 34 kPa (5 psi) of the highest reading after one minute?
Yes No
For HO2S DTCs displayed with misfire DTCs:

GO to H56 .

All other DTCs: GO to H59 GO to HC5 .

.

H55 CHECK INJECTOR FAULT PIDS AND ASSOCIATED DTCS
Access INJ1F-INJ10F PIDs.
Note: If misfire DTCs are present, access only injector fault PIDs corresponding to misfire DTCs.

Is DTC P0201 through P0210 or an injector(s) fault present?
Yes No
GO to H56 . For DTCs P0300 through P0310:

GO to HD12 .

For all other DTCs: GO to H59 .

H56 CHECK FUEL INJECTOR(S) AND HARNESS RESISTANCE
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Note: This erases Continuous Memory DTCs.

Use the injector fault PID to determine the fuel injector circuit(s) requiring testing.

Disconnected PCM.
Measure resistance between suspect fuel injector and VPWR circuits at the PCM harness connector.
Is the resistance between 11.0-18.0 ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

For Continuous Memory DTCs P0202 through P0210: Concern may be intermittent. Attempt to duplicate concern. If unable to duplicate concernGO to Z1 GO to H57 .

H57 CHECK FUEL INJECTOR HARNESS RESISTANCE
Disconnect fuel injector harness connector at the suspect fuel injector.
Measure resistance of VPWR circuit between PCM harness connector pin and the fuel injector harness connector.
Measure resistance of fuel injector circuit between PCM harness connector pin and the fuel injector harness connector.
Is each resistance less than 5.0 ohms?
Yes No
GO to H58 . REPAIR open harness circuit.

H58 CHECK FUEL INJECTOR HARNESS CIRCUIT FOR SHORT TO POWER AND GROUND
Disconnect PCM.
Suspect fuel injector disconnected.
Measure resistance between fuel injector SIG and VPWR circuits; and between fuel injector SIG and PWR GND circuits at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
GO to H59 . REPAIR short circuit.

H59 FLOW TEST FUEL INJECTOR(S)
Use the Rotunda Injector Tester or equivalent to flow test the fuel injectors according to the instructions for the fuel injector tester.
Is the leakage and flow within specification?
Yes No
DTC P0171 and P0174:

GO to H61 .

DTC P0172 and P0175:

Unable to duplicate or identify fault at this time. GO to Z1 .

For DTC P1131, P1151, P2195, and P2197:

GO to H60 .

For DTC P1132, P1152, P2196 and P2198:

GO to H64 . REPLACE fuel injector.

H60 CHECK FOR SECONDARY AIR INTRUSION
Note: If the vehicle is not equipped with Secondary Air Injection System,GO to H61 .

An HO2S always lean condition can be caused by:

Leak in hoses from secondary air injection pump to engine.
Secondary Air diverted upstream of HO2S.
Disconnect secondary air injection hose(s) from engine and plug engine side of secondary air injection system.
Key on, engine running and at operating temperature.
Activate Key On, Engine Running (KOER) Self-Test.
Is DTC P1131, P1151, P2195 or P2197 present?
Yes No
GO to H61 . Cause of DTC(s) is in the Secondary Air Injection System. GO to HM7 for Secondary Air Injection System diagnostics.

H61 INSPECT INDUCTION SYSTEM FOR AIR LEAKS
Inspect the following areas for signs of air leaks:
Inlet tube(s) from air cleaner to the throttle body.
Gaskets which seal the upper and lower intake manifold.
Vacuum hoses and lines for cracks and proper connections.
PCV system.
Are there any signs of leaks or damage?
Yes No
REPAIR as necessary. CONTINUOUS DTCs P0171 or P0174:

Unable to duplicate or identify fault at this time. GO to Z1 .

DTCs P1131, P1151, P2195, and P2197:

GO to H62 .

H62 CHECK CYLINDER COMPRESSION
Note: Use the Misfire DTC(s) displayed on prior DTC retrieval to determine which cylinder's compression to check.

Check cylinder compression. Refer to Engine, Section 303-00, 303-01 in the Workshop Manual.
Are cylinder compression readings within specification?
Yes No
For DTCs P1131, P1151, P2195 and P2197:

GO to H63 .

For DTCs P1132, P1152, P2196 and P2198:

GO to H64 .

Misfire DTCs displayed with fuel control DTCs:

GO to HD20 . REPAIR as necessary.

H63 CHECK HO2S'S ABILITY TO GENERATE A VOLTAGE GREATER THAN 0.5 VOLT
Any vacuum or air leaks can cause DTCs P1131, P1151, P2195 and P2197.

Possible causes:

Water contamination in connector.
Leaking vacuum actuators.
Engine sealing (Intake and IAC).
EGR system (valve).
PCV system (hose and valve).
Unmetered air leaks between throttle body and mass air flow (MAF) sensor assembly.
Inspect HO2S harness for chafing, burned wires or other damage and repair as necessary.
Unplug the suspect HO2S.
Connect digital multimeter to the HO2S Signal and HO2S SIG RTN or HO2S GND at the HO2S sensor connector.
Run engine at 2000 rpm for three minutes.
Rerun KOER Self-Test and monitor HO2S voltage on digital multimeter.
While monitoring, does the voltage ever increase to greater than 0.5 volts?
Yes No
KEY OFF. GO to H70 . KEY OFF. REPLACE HO2S.

H64 ATTEMPT TO GENERATE DTC P1131, P1151, P2195 OR P2197
HO2S disconnected.
Jumper HO2S Signal at the HO2S harness vehicle connector to the battery negative post.
Activate Key On Engine Running (KOER) Self-Test.
Is DTC P1131, P1151, P2195 or P2197present?
Yes No
KEY OFF. REMOVE jumper. GO to H65 . KEY OFF. REMOVE jumper. RECONNECT HO2S. DISCONNECT PCM. INSPECT both ends of connector for damaged or pushed out pins, moisture, corrosion, loose pins and REPAIR as necessary. If OK, REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

H65 HO2S SENSOR VOLTAGE CHECK
HO2S disconnected.
Connect digital multimeter to HO2S SIG circuit and HO2S SIG RTN at the HO2S sensor connector.
Disconnect vacuum hose from vacuum tree.
Start engine and run at 2000 rpm.
Does the voltage reading indicate less than 0.4 volt within 30 seconds?
Yes No
KEY OFF. RECONNECT vacuum hose and HO2S. GO to H70 . KEY OFF. REPLACE HO2S. PERFORM KOER SELF-TEST. If DTCs P1132 or P1152 still exist, REPLACE PCM (refer to Section 2, Flash EEPROM).

H70 MONITOR HO2S (PID) FOR SWITCHING WHILE PERFORMING WIGGLE TEST
Key on, engine running.
Engine at operating temperature.
Note: HO2S displayed as O2S on Scan Tool.

Access suspect HO2S PID.
Wiggle, bend and shake small sections of the Electronic Engine Control harness from the PCM to the HO2S.
Note: Do not compare HO2S switch rate from Bank to Bank as an indication of the sensor's function. It is normal to have a variance in switch ratio from Bank to Bank.

While monitoring the HO2S PID, did the HO2S stop switching?
Yes No
KEY OFF. ISOLATE area of harness concern causing lack of HO2S switches and repair. KEY OFF. GO to H71 .

H71 TEST DRIVE WHILE MONITORING HO2S PID FOR SWITCHING
Note: This test step requires an observer to monitor HO2S PID.

Access HO2S PID.
Access LOOP PID, ensure that vehicle is in Closed Loop before proceeding.
While observer views PIDs, test drive vehicle in a manner consistent with the Freeze Frame Data in an attempt to simulate the original fault.
Does the HO2S switch?
Yes No
KEY OFF. UNABLE to duplicate fault. Testing complete at this time. KEY OFF. REPLACE HO2S.

H80 DTC P0136 AND P0156 MONITOR DOWNSTREAM HO2S OUTPUT VOLTAGE FOR ACTIVITY. DTCs P1137, P1138, P1157, P1158, P2270, P2271, P2272 AND P2273 INDICATE LACK OF HO2S SWITCHING
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Note: It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any KOER HO2S DTCs.

DTC P0136, P1137, P1138, P2270 and P2271=HO2S-12
DTC P0156, P1157, P1158, P2272 and P2273=HO2S-22
Visually inspect for:
pinched, shorted and corroded wiring and pins
water / oil / fluid contamination in HO2S and PCM connectors
crossed sensor wires
contaminated or damaged sensor
Were any concerns found during inspection?
Yes No
REPAIR as necessary. Continuous Memory DTC P0136 and P0156:

GO to H81 .

All others:

GO to H82 .

H81 CHECK FOR KOER DTCS P1137, P1157, P1138, P1158, P2270, P2271, P2272 AND P2273
Key on.
Engine at 2000 rpm for 3 minutes.
Activate KOER Self-Test.
Check for DTCs.
Is DTC P1137, P1138, P1157, P1158, P2270, P2271, P2272 or P2273 present?
Yes No
KEY OFF. GO to H82 . KEY OFF. For DTC P0136 and P0156:

Unable to duplicate or identify at this time. GO to Z1 .

H82 CHECK EXHAUST SYSTEM FOR LEAKS
Note: Any exhaust leaks between the engine and the end of the catalyst can cause DTC P0136 and P0156.

Place vehicle on a hoist, transmission in PARK, emergency brake applied, raise vehicle.
Inspect the following:
Exhaust flanges for leaks.
HO2S torque.
incorrect exhaust installation
aftermarket exhaust
Check for punctures and cracks in catalyst and pipes leading to them.
Is an exhaust leak present?
Yes No
REPAIR as necessary. GO to H83 .

H83 CHECK HO2S HARNESS CIRCUIT FOR SHORT TO VPWR AND GROUND
Disconnect PCM.
Disconnect suspect HO2S.
Measure resistance between HO2S SIG and SIG RTN circuits at the PCM harness connector.
Measure resistance between HO2S SIG circuit and VPWR and VREF circuits at the PCM harness connector.
Measure resistance between HO2S SIG circuit and PWR GND circuit at the PCM harness connector.
Is the resistance greater than 10,000 ohms?
Yes No
GO to H84 . REPAIR short in harness.

H84 CHECK HO2S SIGNAL CIRCUIT AND HO2S SIGNAL RETURN CIRCUITS FOR OPEN IN HARNESS
Measure resistance of VPWR circuit between the PCM harness connector pin and the HO2S harness connector.
Measure resistance of HO2S SIG circuit between the PCM harness connector pin and the HO2S harness connector.
Measure resistance of SIG RTN circuit between the PCM harness connector pin and HO2S SIG RTN vehicle harness connector.
Is the resistance reading less than 5.0 ohms?
Yes No
GO to H85 . REPAIR open circuit.

H85 CHECK HO2S CIRCUIT VOLTAGE
Connect PCM.
Suspect HO2S connected to harness.
Key on, engine off.
Note: HO2S displayed as O2S on Scan Tool.

Access the correct HO2S PID.
Is the voltage greater than 1.5 volts?
Yes No
KEY OFF. GO to H88 . KEY OFF. GO to H86 .

H86 CHECK HO2S GROUND CIRCUIT IN THE PCM
Disconnect PCM.
Measure resistance between SIG RTN and PWR GND circuits at the PCM connector.
Is the resistance reading less than 5.0 ohms?
Yes No
GO to H87 . REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

H87 HO2S CIRCUIT CHECK
PCM connected.
Suspect HO2S disconnected.
Jumper VPWR to HO2S SIG circuit at the HO2S harness connector.
Key on.
Access HO2S PID.
Is the PID value greater than 1.5 volts?
Yes No
REPLACE HO2S. REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ).

H88 CHECK FOR OVER VOLTAGE ON THE HO2S CIRCUIT IN THE PCM
Key on.
HO2S disconnected.
Measure voltage between SIG RTN circuit at the HO2S harness connector and battery negative post.
Measure voltage between HO2S SIG circuit at the HO2S harness connector and battery negative post.
Are either voltage readings greater than 1.5 volts?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPLACE HO2S.

H100 KOER DTC P1127
Address all other DTCs before proceeding with this pinpoint test.
Key on, engine running.
Access all HO2S heaters and HO2S heater monitor PIDs.
Do all PIDs switch or indicate ON?
Yes No
Engine still operating. PERFORM KOER Self-Test. Operate the engine until all PIDs indicate on. PERFORM KOER Self-Test.

H110 DTCS P0040, P0041, P1128 AND P1129 KOER
Note: Refer to the PCM harness connector pin numbers in the beginning of this pinpoint test.

P0040 and P1128 refer to the upstream HO2S.
P0041 and P1129 refer to the downstream HO2S.
Visually inspect vehicle HO2S harness connector(s) for any indication of being crossed (stretched wires, wire harnesses not mounted properly).
Are there crossed connections or wires?
Yes No
REPAIR as necessary. GO to H111 .

H111 VERIFY PROPER HO2S SIGNAL PIN LOCATION
PCM disconnected.
Disconnect both of the suspect HO2S sensors from the vehicle harness connector.
P0040 and P1128 = HO2S 11/21 Upstream
P0041 and P1129 = HO2S 12/22 Downstream
Measure resistance of HO2S signal circuits between PCM harness connector pins and HO2S harness connector.
Is the resistance less than 5.0 ohms?
Yes No
Unable to duplicate or identify at this time. GO to Z1 . CONNECT HO2S connector to proper HO2S signal pins in the PCM harness connector or HO2S harness connectors. RERUN Quick Test.

H115 CHECK HO2S CIRCUIT VOLTAGE
Visually inspect the HO2S circuit for exposed wiring, water contamination, corrosion and proper assembly.
On some applications, a hoist is required to access the HO2S harness.
Key on, engine running
Note: HO2S is displayed as O2S on Scan Tool.

Access suspect HO2S PID(s).
P0132 = HO2S-11
P0138 = HO2S-12
P0152 = HO2S-21
P0158 = HO2S-22
Is PID voltage 1.5 volts or greater?
Yes No
GO to H116 . Concern may be intermittent. Attempt to duplicate concern, perform wiggle test on suspect circuit harness and component.

If concern was reproduced: Perform this Pinpoint test again.

All others:GO to Z1

H116 CHECK HO2S SIGNAL FOR SHORT TO POWER INSIDE OF SENSOR
Key off.
Suspect HO2S disconnected.
Key on, engine off.
Access suspect HO2S PID(s).
Note: If viewing the HO2S11 (O2S11) PID on the 2.3L Focus, the engine must be running.

Is PID voltage .5 volts or greater?
Yes No
GO to H117 Replace HO2S sensor.

H117 CHECK HO2S SIGNAL FOR SHORT TO POWER IN HARNESS
Key off.
Suspect HO2S disconnected.
PCM disconnected.
Check resistance between HO2S Signal circuit and both VPWR and VREF circuits at the PCM connector.
Are resistance values greater than 10,000 Ohms?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). Repair short to power in harness between PCM and HO2S.




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[Haus]

well since i disconnected the vacuum line from the FPR and plugged the line, the code has not come back. even after like 500 miles of driving. i get system pass on both KOEO and KOER tests.

cause with the line connected i was getting like 32 psi of FP and with the line disconnected i was getting 41 psi. so the codes disappeared with the higher Fuel pressure.

 

[hotcobra03]

fuel pressure

well since i disconnected the vacuum line from the FPR and plugged the line, the code has not come back. even after like 500 miles of driving. i get system pass on both KOEO and KOER tests.

cause with the line connected i was getting like 32 psi of FP and with the line disconnected i was getting 41 psi. so the codes disappeared with the higher Fuel pressure.

damn that took awile...what i learned is that you failed step 1/2 ..looks like you got fuel pressure problems/restrictions ...these guys are great to learn from...give a follow-up when trouble shooting fuel systems

 

[dz01]

This is an old thread, but some good info here. Although disconnecting and plugging the FPR line got the codes to disappear, would the permanent to be replace the fuel pump? I'm thinking of plugging my line just to see if my codes disappear. I've tested by fuel pressure and it seems where it should be.