2005 MY OBD System Operation Summary for Gasoline Engines

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!The Catalyst Efficiency Monitor uses an oxygen sensor before and after the catalyst to infer the hydrocarbonefficiency based on oxygen storage capacity of the ceria and precious metals in the washcoat. Under normal,closed-loop fuel conditions, high efficiency catalysts have significant oxygen storage. This makes the switchingfrequency of the rear HO2S very slow and reduces the amplitude of those switches as compared to the switchingfrequency and amplitude of the front HO2S. As catalyst efficiency deteriorates due to thermal and/or chemicaldeterioration, its ability to store oxygen declines. The post-catalyst HO2S signal begins to switch more rapidly withincreasing amplitude, approaching the switching frequency and amplitude of the pre-catalyst HO2S. Thepredominant failure mode for high mileage catalysts is chemical deterioration (phosphorus deposition on the frontbrick of the catalyst), not thermal deterioration.All applications utilize an FTP-based (Federal Test Procedure) catalyst monitor. This simply means that thecatalyst monitor must run during a standard FTP emission test as opposed to the 20-second steady-state catalystmonitor used in 1994 through some 1996 vehicles. Two slightly different versions of the catalyst monitor are usedfor 2001 MY and beyond vehicles. Both versions will continue to be used in subsequent model years." #$#%&''( )In order to assess catalyst oxygen storage, the monitor counts front and rear HO2S switches during part-throttle,closed-loop fuel conditions after the engine is warmed-up and inferred catalyst temperature is within limits. Frontswitches are accumulated in up to nine different air mass regions or cells although 3 air mass regions is typical.Rear switches are counted in a single cell for all air mass regions. When the required number of front switches hasaccumulated in each cell (air mass region), the total number of rear switches is divided by the total number of frontswitches to compute a switch ratio. A switch ratio near 0.0 indicates high oxygen storage capacity, hence high HCefficiency. A switch ratio near 1.0 indicates low oxygen storage capacity, hence low HC efficiency. If the actualswitch ratio exceeds the threshold switch ratio, the catalyst is considered failed.*$#%&+)In order to assess catalyst oxygen storage, the catalyst monitor counts front HO2S switches during part-throttle,closed-loop fuel conditions after the engine is warmed-up and inferred catalyst temperature is within limits. Frontswitches are accumulated in up to three different air mass regions or cells. While catalyst monitoring entryconditions are being met, the front and rear HO2S signal lengths are continually being calculated. When therequired number of front switches has accumulated in each cell (air mass region), the total signal length of the rearHO2S is divided by the total signal length of front HO2S to compute a catalyst index ratio. An index ratio near 0.0indicates high oxygen storage capacity, hence high HC efficiency. An index ratio near 1.0 indicates low oxygenstorage capacity, hence low HC efficiency. If the actual index ratio exceeds the threshold index ratio, the catalyst isconsidered failed.!If the catalyst monitor does not complete during a particular driving cycle, the already-accumulated switch/signallengthdata is retained in Keep Alive Memory and is used during the next driving cycle to allow the catalyst monitora better opportunity to complete, even under short or transient driving conditions.Rear HO2S sensors can be located in various ways to monitor different kinds of exhaust systems. In-line enginesand many V-engines are monitored by individual bank. A rear HO2S sensor is used along with the front, fuelcontrolHO2S sensor for each bank. Two sensors are used on an in-line engine; four sensors are used on a V-engine. Some V-engines have exhaust banks that combine into a single underbody catalyst. These systems arereferred to as Y-pipe systems. They use only one rear HO2S sensor along with the two front, fuel-control HO2Ssensors. Y-pipe system use three sensors in all. For Y-pipe systems, the two front HO2S sensor signals arecombined by the software to infer what the HO2S signal would have been in front of the monitored catalyst. Theinferred front HO2S signal and the actual single, rear HO2S signal is then used to calculate the switch ratio.FORD MOTOR COMPANY REVISION DATE: APRIL 28, 2004 PAGE 4 OF 131
Most vehicles that are part of the “LEV” catalyst monitor phase-in will monitor less than 100% of the catalystvolume – often the first catalyst brick of the catalyst system. Partial volume monitoring is done on LEV and ULEVvehicles in order to meet the 1.75 * emission-standard. The rationale for this practice is that the catalysts nearestthe engine deteriorate first, allowing the catalyst monitor to be more sensitive and illuminate the MIL properly atlower emission standards.Many applications that utilize partial-volume monitoring place the rear HO2S sensor after the first light-off catalystcan or, after the second catalyst can in a three-can per bank system. (A few applications placed the HO2S in themiddle of the catalyst can, between the first and second bricks.)Index ratios for ethanol (Flex fuel) vehicles vary based on the changing concentration of alcohol in the fuel. Themalfunction threshold typically increases as the percent alcohol increases. For example, a malfunction threshold of0.5 may be used at E10 (10% ethanol) and 0.9 may be used at E85 (85% ethanol). The malfunction thresholds aretherefore adjusted based on the % alcohol in the fuel. (Note: Normal gasoline is allowed to contain up to 10%ethanol (E10)).All vehicles employ an Exponentially Weighted Moving Average (EWMA) algorithm to improve the robustness ofthe FTP catalyst monitor. During normal customer driving, a malfunction will illuminate the MIL, on average, in 3 to6 driving cycles. If KAM is reset (battery disconnected), a malfunction will illuminate the MIL in 2 driving cycles. Seethe section on EWMA for additional information.CATALYST MONITOR OPERATION:DTCs P0420 Bank 1 (or Y-pipe), P0430 Bank 2Monitor executionMonitor SequenceSensors OKMonitoring Durationonce per driving cycleHO2S response test complete and no DTCs (P0133/P0153) prior tocalculating switch ratio, no SAIR pump stuck on DTCs (P0412/P1414), noevap leak check DTCs (P0442/P0456), no EGR stuck open DTCs (P0402)ECT, IAT, TP, VSS, CKPApproximately 700 seconds during appropriate FTP conditions(approximately 100 to 200 oxygen sensor switches are collected)TYPICAL SWITCH RATIO CATALYST MONITOR ENTRY CONDITIONS:Entry condition Minimum MaximumTime since engine start-up (70 o F start)330 secondsEngine Coolant Temp 170 o F 230 o FIntake Air Temp 20 o F 180 o FEngine Load 10%Throttle Position Part Throttle Part ThrottleTime since entering closed loop fuel30 secVehicle Speed 5 mph 70 mphInferred Catalyst Mid-bed Temperature900 o FEGR flow (Note: an EGR fault disables EGR) 1% 12%Fuel Level 15%Steady Air Mass Flow for each Air Mass cell (typically three cells) 1.0 lb/min 5.0 lb/min(Note: FTP cycle is biased towards the low air mass range, 25 - 35 mph steady state driving must beperformed to complete the monitor)FORD MOTOR COMPANY REVISION DATE: APRIL 28, 2004 PAGE 5 OF 131
Page 1: Table of ContentsIntroduction - OBD
Page 6 and 7: TYPICAL INDEX RATIO CATALYST MONITO
Page 8 and 9: There are three different misfire m
Page 10 and 11: 0#1The acceleration that a piston u
Page 12 and 13: J1979 Misfire Mode $06 DataTest ID
Page 14 and 15: 0$Secondary air systems typically u
Page 16 and 17: 201 34536/#/Vehicles that meet enha
Page 18 and 19: 0.040” EVAP Monitor Operation:DTC
Page 20 and 21: 201 3536/#/Some vehicles that meet
Page 22 and 23: slosh. If the monitor aborts, it wi
Page 24 and 25: 0.020” EVAP Monitor Operation:DTC
Page 26 and 27: Test ID Comp ID Description for J18
Page 28 and 29: Ford's EONV implementation for Cali
Page 30 and 31: 1#4;!In this phase, the EONV test i
Page 32 and 33: 0.020” EONV EVAP Monitor Operatio
Page 34 and 35: 201!!#/Additional malfunctions that
Page 36 and 37: Fuel Tank Pressures Sensor Offset C
Page 38 and 39: :As fuel system components age or o
Page 40 and 41: -:-The time between HO2S switches i
Page 42 and 43: $-A functional test of the rear HO2
Page 44 and 45: -- 3 amps, (NTK)< 0.400 amps or > 3
Page 46 and 47: 1:$The Delta Pressure Feedback EGR
Page 48 and 49: If an EGR system malfunction is det
Page 50 and 51: After the vehicle has warmed up and
Page 52 and 53: 1:$In the 2002.5 MY, Ford introduce
Page 54 and 55:
The ESM may provide the PCM with a
Page 56 and 57:
Next, the differential pressure ind
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I/M Readiness IndicationIf the infe
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The Stepper Motor EGR Monitor consi
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Note: BARO is inferred at engine st
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$. 6The Electric Stepper Motor EGR
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The MAP sensor is also checked for
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When the entry conditions for the f
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1!2Ford plans to comply with the PC
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ETC System Failure Mode and Effects
Page 74 and 75:
;#11!%;11!)The purpose of the TPPC
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Currently, vehicles use either an E
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Fuel Rail Pressure Sensor Check Ope
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Loss of Keep Alive Memory (KAM) pow
Page 82 and 83:
CKP Ignition System Check Operation
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The Idle Air Control (IAC) solenoid
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There are several different styles
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The PCM continually calculates a ca
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Most vehicle applications no longer
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Intermediate Shaft Speed Sensor Fun
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Primary Pulley Speed Sensor Functio
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Secondary Pulley Pressure Sensor Ch
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Typical Shift Solenoid mechanical f
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Shift Completion Check Operation:DT
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Pressure Control Solenoid Check Ope
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Forward Clutch/Reverse Clutch Solen
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4$=%$> );4R70E is the replacement f
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! 4%:> );;The Analog Transmission R
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$%$> );;The Digital Transmission Ra
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Direct One Way ClutchThe Direct One
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Direct One Way ClutchThe Direct One
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$&&> %$> );;Transmission Range Sens
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4:=%:.)%:> );;The Transmission Rang
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CFT 30 Mechatronic Illustration;Tra
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Internal TCM Power SupplyIf the pow
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shift, rpm does not go up during a
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The shift solenoids are monitored f
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*> #606Exponentially Weighted Movin
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@$!The readiness function is implem
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2005 MY OBD System Operation Summary for Gasoline Engines

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