VEHICLE CHECK AND PREPARATION
Before using the scan tool to carry out any test, see the important Safety Notice, refer to NOTE, NOTICE, CAUTION AND WARNING and the necessary visual checks listed below.
Visual Checks
- Inspect the air cleaner and inlet duct.
- Check all engine vacuum hoses for damage, leaks, cracks, kinks, and proper routing.
- Check the electronic engine control (EEC) system wiring harness for proper connections, bent or broken pins, corrosion, loose wires, and proper routing.
- Check the PCM, sensors, and actuators for physical damage.
- Check the engine coolant for proper level and mixture.
- Check the transmission fluid level and quality.
- Make all necessary repairs before continuing with the quick test. For additional information, refer to «QUICK TEST DESCRIPTION»(ref-608990-S20491744862014041200000) .
Vehicle Preparation
- Carry out all safety steps required to start and run vehicle tests. Apply the parking brake, place the gear selector lever firmly into the PARK position on automatic transmission vehicles or NEUTRAL on manual transmission vehicles, and block the drive wheels.
- Turn off all electrical loads such as radios, lamps, A/C, blower, and fans.
- Start the engine (if the engine runs) and bring it up to the normal operating temperature before running the quick test.
One Touch Integrated Start System
Some vehicles are equipped with one touch integrated start system. It may be necessary to disable the one touch integrated start system to carry out diagnostic procedures that require extended cranking. Connect the scan tool, access the PCM and select the one touch integrated start system control PID to disable the system.
Generic OBD PID List
An X in the Freeze Frame column denotes both a mode 1 and mode 2 PID (real time and freeze frame).
| Freeze Frame | Acronym | Description | Measurement Units |
|---|---|---|---|
| X | APP_D | Accelerator Pedal Position D | % |
| X | APP_E | Accelerator Pedal Position E | % |
| X | BARO | Barometric Pressure | KPa |
| X | CATEMP11 | Catalyst Temperature Bank 1, Sensor 1 | Degrees |
| X | CATEMP12 | Catalyst Temperature Bank 1, Sensor 2 | Degrees |
| X | CATEMP21 | Catalyst Temperature Bank 2, Sensor 1 | Degrees |
| X | CATEMP22 | Catalyst Temperature Bank 2, Sensor 2 | Degrees |
| X | CLRDIST Distance | Since Codes Cleared | Km/mi |
| X | CLRWRMUP | Number Of Warm Ups Since DTCs Cleared | Units |
| X | ECT | Engine Coolant Temperature | Degrees |
| X | EGRPCT | Commanded EGR | % |
| X | EGR_ERR | EGR Error | % |
| X | EVAP_VP | Evaporative System Vapor Pressure | KPa |
| X | EQ_RAT | Commanded Equivalence Ratio | Unit |
| X | FLI | Fuel Level Input | % |
| X | FRP | Fuel Rail Pressure | KPa |
| X | FUEL SYS1 | Fuel System Feedback Control Status Bank 1 | Open Loop/Closed Loop |
| X | FUEL SYS2 | Fuel System Feedback Control Status Bank 2 | Open Loop/Closed Loop |
| X | IAT | Intake Air Temperature | Degrees |
| X | LOAD | Calculated Engine Load | % |
| X | LOAD_ABS | Absolute Load Value | % |
| X | LONGFT1 | Current Bank 1 Fuel Trim Adjustment (kamref1) From Stoichiometry Which Is Considered Long Term | % |
| X | LONGFT2 | Current Bank 2 Fuel Trim Adjustment (kamref2) From Stoichiometry Which Is Considered Long Term | % |
| X | MAF | Mass Airflow Rate | G/s-lb/min |
| X | MAP | Manifold Absolute Pressure | Volts/kPa PSI/in-Hg |
| X | MIL_DIST | Distance Traveled with MIL ON | Kilometer |
| X | O2S11 | Bank 1 Upstream Oxygen Sensor (11) | Volts |
| X | O2S12 | Bank 1 Downstream Oxygen Sensor (12) | Volts |
| X | O2S13 | Bank 1 Downstream Oxygen Sensor (13) | Volts |
| X | O2S21 | Bank 2 Upstream Oxygen Sensor (21) | Volts |
| X | O2S22 | Bank 2 Downstream Oxygen Sensor (22) | Volts |
| X | O2S23 | Bank 2 Downstream Oxygen Sensor (23) | Volts |
| OBDSUP | On Board Diagnostic System | OBD II OBD I OBD Combination of or None | |
| X | PTO | Power Take Off Status | On/Off |
| X | RPM | Revolutions Per Minute | RPM |
| X | RUNTM | Run Time | Seconds |
| X | SHRTFT1 | Current Bank Fuel Trim Adjustment (lambse1) From Stoichiometry Which Is Considered Short Term | % |
| X | SHRTFT2 | Current Bank 2 Fuel Trim Adjustment (lambse1) From Stoichiometry Which Is Considered Short Term | % |
| X | SPARKADV | Spark Advance Requested | Degrees |
| X | TAC_PCT | Commanded Throttle Actuator | % |
| X | TP | Throttle Position | % |
| X | TP | REL Relative Throttle Position | % |
| VSS | Vehicle Speed Sensor | Km/h-mph |
Ford PID List
Note. This is not a complete list of Ford PIDs available. This is a list of Ford PIDs in this information .
| PID | Description | Ford Units |
|---|---|---|
| AAT | Ambient Air Temperature | Degrees |
| AAT_V | Ambient Air Temperature Voltage | Volts |
| AEIS_ACTION | Number Of Drive Cycles Where Automatic Engine Idle Shutdown Occurred | Count |
| AEIS_POSS | Number Of Drive Cycles Where Automatic Engine Idle Shutdown Possible | Count |
| APP | Accelerator Pedal Position | Percent |
| APP1 | Accelerator Pedal Position 1 | Volts |
| APP2 | Accelerator Pedal Position 2 | Volts |
| APP_MAXDIFF | Maximum Difference Between APP1 And APP2 | Degrees |
| APP_MODE | Accelerator Pedal Position Mode | Pedal Position |
| AXLE | Axle Ratio | Ratio |
| B+ | Battery Voltage | Volts |
| BARO | Barometric Pressure Sensor | Frequency/Pressure |
| BOO | Brake Pedal Position (BPP) Switch | On/Off |
| BOO1 | Brake Pedal Position (BPP) Switch | On/Off |
| BOO2 | Brake Pressure Applied | On/Off |
| BPP/BOO | Brake Pedal Position (BPP) Switch | On/Off |
| BRKOVRD_POSS | Number Of Drive Cycles In Which Brake Override Accelerator Action Possible | Numeric Value |
| BRKOVR_ACTION | Number Of Drive Cycles Where Brake Override Accelerator Action Occurred | Numeric Value |
| CAC_T | Charge Air Cooler Temperature Degrees | F |
| CAC_V | Charge Air Cooler Voltage | Volts |
| CACCT | Charge Air Cooler (CAC) Coolant Temperature Sensor | Degrees F |
| CACCT_V | Charge Air Cooler (CAC) Coolant Temperature Sensor Voltage | Volts |
| CAT_EVAL | Catalyst Evaluated | Yes/No |
| CHT | Cylinder Head Temperature Input | Volt/Degrees F |
| CLRDIST | Distance Since DTCs Cleared | Miles |
| CLRWRMUP | Number Of Warm-Ups Since DTCs Cleared | Count |
| CPP_BOT | Clutch Pedal At Or Near Bottom Of Travel | Yes/No |
| CPP | Clutch Pedal Position Switch Input | On/Off |
| CPP/PNP | Clutch Pedal Position/Park Neutral Position Switch Input | Neutral/Drive |
| DECHOKE | Crank Fueling Disabled | Yes/No |
| DIST_AEIS | Distance Since Automatic Engine Idle Shutdown Occurred | Miles |
| DIST_BRKOVRD | Distance Since Brake Override Accelerator Action Occurred | Miles |
| DPFEGR | Differential Pressure Feedback EGR Input | Volts |
| ECT | Engine Coolant Temperature Input | Volts/Degrees F |
| EGRMC1F | EGR Motor Control Fault | Fault/No Fault |
| EGRMC2F | EGR Motor Control Fault | Fault/No Fault |
| EGRMC3F | EGR Motor Control Fault | Fault/No Fault |
| EGRMC4F | EGR Motor Control Fault | Fault/No Fault |
| EGRMDSD | Electric EGR Motor Commanded In Steps | On/Off |
| EGRPCT | Commanded EGR | Percent |
| EGRVR | EGR Valve Vacuum Control | Percent |
| EGR_EVAL | EGR Evaluated | Yes/No |
| EGR_STEP | EGR Valve Motor Position | Position |
| EONV_RDY | EVAP Monitor Test Ready At Next Key Off | Ready/Not Ready |
| EQ_RAT11 | Equivalence Ratio Lambda Bank 1, Sensor 1 | Ratio |
| EQ_RAT21 | Equivalence Ratio Lambda Bank 2, Sensor 1 | Ratio |
| ETC_ACT | Electronic Throttle Control Actual | Degrees |
| ETC_DSD | Electronic Throttle Control Desired | Degrees |
| ETC_TRIM | Electronic Throttle Control Trim | Degrees |
| EVAP020C | Evaporative Emissions Monitor | Yes/No |
| EVAP020D | Evaporative Emissions Monitor | Allow/Disallow |
| EVAP020R | Evaporative Emissions Monitor | Ready/Not Ready |
| EVAPCP | Evaporative Emissions Canister Purge Valve | Percent/On/Off |
| EVAPCV | Evaporative Emissions Canister Purge Vent Control | Percent/On/Off |
| EVAPCV_F | Evaporative Emissions Canister Purge Vent Fault | Fault/No Fault |
| EVAPSOAK | Evaporative Emissions Monitor Soak Conditions Are Met | Yes/No |
| EVAPSTA | Evaporative Emissions Monitor Completed Cycle | Status |
| EVAP_ACTIVE | Evaporative Emissions Activation Switch Position At Start Detection | Yes/No |
| EVAP_EVAL | Evaporative Emissions Monitor Evaluated | Yes/No |
| EVAP_SWITCH | Evaporative Emissions Actual Switch | Open/Closed |
| EVMV | Electronic Vapor Management Valve Commanded Current | Current |
| FAN | Engine Cooling Fan Operation | On/Off |
| FANDC | Variable Speed Fan Duty Cycle | Percent |
| FAN_DSD | Fan Speed Desired | Percent |
| FANSS | Fan Speed Sensor Signal | RPM |
| FANVAR | Variable Speed Fan Output | Percent |
| FANVAR_F | Variable Speed Fan Output Fault | Fault/No Fault |
| FCIL | Fuel Cap Indicator Light | On/Off |
| FF_INF | Inferred Flex Fuel | Percent |
| FLI | Fuel Level Indicator Input | Percent |
| FLP | Low Side Fuel Pressure | Pressure |
| FP | Fuel Pump | Percent/On/Off |
| FPM | Fuel Pump Secondary Monitor | Percent/On/Off |
| FPM2 | Fuel Pump Secondary 2 Monitor | Percent/On/Off |
| FPM_STAT | Fuel Pump Monitor Status | Fault/No Fault |
| FRP | Fuel Rail Pressure Input | Volts/Pressure |
| FRP_DSD | Fuel Rail Pressure | Desired Pressure |
| FRT | Fuel Rail Temperature | Degrees F/Volts |
| FTP | Fuel Tank Pressure Input | Volts/Pressure |
| FTP_H2O | Fuel Tank Pressure Input | Pressure |
| FTP_INF | Inferred Fuel Tank Pressure | Pressure |
| FUELPW1 | Injector Pulse Width Bank 1 | Time |
| FUELPW2 | Injector Pulse Width Bank 2 | Time |
| FUELSYS | Fuel System Status | Open Loop/ Closed Loop |
| F_VCV | Fuel Volume Control Valve | Percent |
| GEAR | Transmission Gear Status | Gear |
| HFC | High Speed Fan Control | On/Off |
| HTR11 | Bank 1 Sensor 1 HO2S Heater Control | On/Off |
| HTR11F | Bank 1 Sensor 1 HO2S Heater Circuit Fault | Fault/No Fault |
| HTR12 | Bank 1 Sensor 2 HO2S Heater Control | On/Off |
| HTR12F | Bank 1 Sensor 2 HO2S Heater Circuit Fault | Fault/No Fault |
| HTR21 | Bank 2 Sensor 1 HO2S Heater Control | On/Off |
| HTR21F | Bank 2 Sensor 1 HO2S Heater Circuit Fault | Fault/No Fault |
| HTR22 | Bank 2 Sensor 2 HO2S Heater Control | On/Off |
| HTR22F | Bank 2 Sensor 2 HO2S Heater Circuit Fault | Fault/No Fault |
| HTRCM11 | Bank 1 Sensor 1 O2S Heater Circuit Current | Current |
| HTRCM12 | Bank 1 Sensor 2 O2S Heater Circuit Current | Current |
| HTRCM21 | Bank 2 Sensor 1 O2S Heater Circuit Current | Current |
| HTRCM22 | Bank 2 Sensor 2 O2S Heater Circuit Current | Current |
| HTRX1 | HO2S Sensor 1 (Upstream) Heater Control | On/Off |
| HTRX2 | HO2S Sensor 2 (Downstream) Heater Control | On/Off |
| HO2S11 | Bank 1 Sensor 1 HO2S Input | Volts |
| HO2S12 | Bank 1 Sensor 2 HO2S Input | Volts |
| HO2S21 | Bank 2 Sensor 1 HO2S Input | Volts |
| HO2S22 | Bank 2 Sensor 2 HO2S Input | Volts |
| IAC | Idle Air Control | Percent |
| IACTRIM | Short Term Airflow Trim | Numeric Value |
| IAT | Intake Air Temperature Input | Degrees F/Volts |
| IAT2 | Intake Air Temperature Sensor 2 Input | Degrees F/Volts |
| IGN_R/S | Ignition Switch Run/Start | On/Off |
| IMTV | Intake Manifold Tuning Valve Control | Percent |
| INJ1F-8F | Fuel Injector Primary Fault (Cylinders 1-8) | Fault/No Fault |
| INJ9F-10F | Fuel Injector Primary Fault (Cylinders 9 and 10) | Fault/No Fault |
| INJPWR_M | Injectors Circuit Voltage Monitor | Volts |
| KNOCK1 | Knock Sensor 1 Signal | Count |
| KNOCK2 | Knock Sensor 2 Signal | Count |
| LFC | Low Speed Fan Control | On/Off |
| LOAD | Calculated Engine Load | Percent |
| LONGFT1 | Long Term Fuel Trim Bank 1 | Percent |
| LONGFT2 | Long Term Fuel Trim Bank 2 | Percent |
| MAF | Mass Airflow Rate Input | Frequency/Volts/Mass Flow |
| MAP | Intake Manifold Absolute Pressure | Frequency/Volts/Pressure |
| MAP_DMD | Manifold Absolute Pressure Demanded | Pressure |
| MIL | Malfunction Indicator Lamp Control | On/Off |
| MIL_DIS | Distance Since MIL Was Activated | Miles |
| MISFIRE | Misfire Status | Yes/No |
| MP_LRN | Learned Misfire Correction Profile | Yes/No |
| NM | Number Of Misfires | Count |
| NUM | Misfire Events During Latest Misfire Cycle | Count |
| O2BANK1 | Bank 1 O2S Status | Rich/Lean |
| O2BANK2 | Bank 2 O2S Status | Rich/Lean |
| O2S11 | Bank 1 Sensor 1 O2S Input | Volts |
| O2_DS_DISBL | Downstream Oxygen Sensor Fuel Control Disabled | Yes/No |
| O2_DS1_ERR | Downstream Closed Loop Input Error Bank 1 | Volts |
| O2_DS2_ERR | Downstream Closed Loop Input Error Bank 2 | Volts |
| O2S11_CUR | Bank 1 Sensor 1 Current | Current |
| O2S11_HTR | Commanded Duty Cycle For The O2S11 Heater Output | Percentage |
| O2S11_IMPED | O2S11 Sensor Impedance | Volts |
| O2S11_READY | O2S11 Is Warm And Ready To Operate | Yes/No |
| O2S11_STAT | O2S11 Status Fault/No | Fault |
| O2S11_TR | O2 Sensor Trim Circuit Resistance 11 | Resistance |
| O2S12 | Bank 1 Sensor 2 O2S Input | Volts |
| O2S21 | Bank 2 Sensor 1 O2S Input | Volts |
| O2S21_CUR | Bank 2 Sensor 1 Current | Current |
| O2S21_HTR | Commanded Duty Cycle For The O2S21 Heater Output | Percentage |
| O2S21_IMPED | O2S21 Sensor Impedance | Volts |
| O2S21_READY | O2S21 Is Warm And Ready To Operate | Yes/No |
| O2S21_STAT | O2S21 Status | Fault/No Fault |
| O2S21_TR | O2 Sensor Trim Circuit Resistance 21 | Resistance |
| O2S22 | Bank 2 Sensor 2 O2S Input | Volts |
| O2S_EVAL | Oxygen Sensor Circuits Evaluated | Yes/No |
| O2SHTR_EVAL | Oxygen Sensor Heater Circuits Evaluated | Yes/No |
| OSS | Output Shaft Speed | RPM |
| PTO | Power Take Off Status Input | On/Off |
| PTOLOAD | Power Take Off Engage Input | Yes/No |
| PTOIR_V | Power Take Off RPM Select Input | Volts |
| PTOIL | Power Take Off Indicator Lamp Output | On/Off |
| RO2FT1 | Rear O2 Fuel Trim - Bank 1 | Percentage |
| RO2FT2 | Rear O2 Fuel Trim - Bank 2 | Percentage |
| RPM | Engine Speed Based Upon CKP Input | RPM |
| RPMDSD | RPM Desired | RPM |
| SCBC | Supercharger Bypass Control | On/Off |
| SCIP_V | Supercharger Inlet Pressure | Volts |
| SHRTFT | Short Term Fuel Trim | Percent |
| SHRTFT1 | Short Term Fuel Trim Bank 1 | Percent |
| SHRTFT2 | Short Term Fuel Trim Bank 2 | Percent |
| SPARK_ACTUAL | Spark Advance Actual | Degrees |
| SPARKADV | Spark Advance | Degrees |
| SPKDUR_1-8 | Spark Duration (Cylinders 1-8) | Time |
| SS_OUTOP | Stop Start Coordination Out Of Operation | Status |
| SS_START_ERR | Stop Start Coordination Start Error | Status |
| SS_STOP_ERR | Stop Start Coordination Stop Error | Status |
| STARTER_CNTS | Starter Motor Activation Counter | Count |
| STRT_RLY | Starter Relay | Enabled/Disabled |
| SYNC | CMP And CKP Synchronized | Yes/No |
| TCBP | Measured Boost At Throttle Inlet Pressure Sensor | KPa/psi |
| TCBP_V | Throttle Inlet Pressure Sensor Voltage | Volts |
| THROTTLE_CMD | Commanded Throttle Actuator Control | Percent |
| TORQUE | Net Torque Into Torque Converter | Torque |
| TP | Throttle Position Input | Volts/Percent |
| TPCT | Lowest Closed Throttle Voltage | Volts |
| TP_MAXDIFF | Maximum Angle Difference Between TP1 And TP2 | Degrees |
| TPMODE | Throttle Position | Closed/Part/ Wide Open Throttle |
| TP1 | Throttle Position 1 Voltage | Volts |
| TP2 | Throttle Position 2 Voltage | Volts |
| TP_B | Absolute Throttle Position B | Percent |
| TP1_ADP_CLSD | Throttle Position 1 Adaption Voltage Closed Stop | Volts |
| TP1_ADP_LIMP | Throttle Position 1 Adaption Voltage At Limp Home | Volts |
| TP1_ADP_MINAIR | Throttle Position 1 Adaption Volt Minimum Airflow | Volts |
| TP2_ADP_CLSD | Throttle Position 2 Adaption Voltage Closed Stop | Volts |
| TP2_ADP_LIMP | Throttle Position 2 Adaption Voltage At Limp Home | Volts |
| TQ_CNTRL | Torque Fuel/Spark Limiting Status | Status |
| TRIP | CNT OBD II Trips Completed | Count |
| TURBO_BP1_STAT | Turbocharger Bypass 1 Status | Fault/No Fault |
| TURBO_BP2_STAT | Turbocharger Bypass 2 Status | Fault/No Fault |
| TURBO_BPASS | Turbocharger Bypass Valve | Percent |
| TURBO_BPASS_2 | Turbocharger Bypass Valve 2 | Percent |
| TURBO_OVER | Turbocharger Overboost Condition | Fault/No Fault |
| TURBO_UNDER | Turbocharger Underboost Condition | Fault/No Fault |
| TURBO_WGATE | Turbocharger Wastegate | Percent |
| TWGATE_STAT | Turbocharger Wastegate Status | Fault/No Fault |
| VCTADV | Variable Cam Timing Advance | Degrees |
| VCTADV2 | Variable Cam Timing Advance 2 | Degrees |
| VCTADVERR | Variable Cam Timing Advance Error | Degrees |
| VCTADVERR2 | Variable Cam Timing Advance 2 Error | Degrees |
| VCTDC | Variable Cam Timing Advance Duty Cycle | Percent |
| VCTDC2 | Variable Cam Timing Advance Duty Cycle | Percent |
| VCT_EXH_ACT1 | Actual Exhaust B Camshaft Position Bank 1 | Degrees |
| VCT_EXH_ACT2 | Actual Exhaust B Camshaft Position Bank 2 | Degrees |
| VCT_EXH_DC1 | Exhaust B Camshaft Position Duty Cycle Bank 1 | Percent |
| VCT_EXH_DC2 | Exhaust B Camshaft Position Duty Cycle Bank 2 | Percent |
| VCT_EXH_DIF1 | Exhaust B Camshaft Desired Minus Actual Bank 1 | Degrees |
| VCT_EXH_DIF2 | Exhaust B Camshaft Desired Minus Actual Bank 2 | Degrees |
| VCT_EXH_DSD | VCT Exhaust Angle Desired | Degrees |
| VCT_EXH_DSD1 | VCT Exhaust Angle Desired Bank 1 | Degrees |
| VCT_INT_ACT1 | Actual Intake A Camshaft Position Bank 1 | Degrees |
| VCT_INT_ACT2 | Actual Intake A Camshaft Position Bank 2 | Degrees |
| VCT_INT_DC1 | Intake A Camshaft Position Duty Cycle Bank 1 | Percent |
| VCT_INT_DC2 | Intake A Camshaft Position Duty Cycle Bank 2 | Percent |
| VCT_INT_DIF1 | Intake A Camshaft Desired Minus Actual Bank 1 | Degrees |
| VCT_INT_DIF2 | Intake A Camshaft Desired Minus Actual Bank 2 | Degrees |
| VCT_INTK_DSD | VCT Intake Angle Desired | Degrees |
| VCT Intake Angle Desired Bank 1 | Degrees | |
| VCTSYS | Variable Cam Timing System Status | Open/Closed |
| VCT1_F | Variable Cam Timing Fault | Fault/No Fault |
| VCT2_F | Variable Cam Timing 2 Fault | Fault/No Fault |
| VPWR | Vehicle Power Voltage | Volts |
| VREF | Vehicle Reference Voltage | Volts |
| VSS | Vehicle Speed | Speed |
| WGATE_PRES | Wastegate Control Absolute Pressure Sensor | Pressure |
| WGATE_PRES_F | Wastegate Control Pressure Sensor Status | Fault/No Fault |
| WGATE_V | Wastegate Control Pressure Sensor Voltage | Volts |
| WGATE_VAC_DSD | Desired Wastegate Control Vacuum | Pressure |
| WGATE_VAC_INF | Wastegate Control Vacuum Inferred | Pressure |
OBDII Freeze Frame Data
Freeze frame data allows access to emission related values from specific generic parameter identification (PID). These values are stored when an emission related diagnostic trouble code (DTC) is stored in continuous memory. This provides a snapshot of the conditions that were present when the DTC was stored. Once one set of freeze frame data is stored, this data remains in memory even if another emission related DTC is stored, with the exception of misfire or fuel system DTCs. Once freeze frame data for a misfire or fuel system DTC is stored it overwrites any previous data, and freeze frame data is no longer overwritten. When a DTC associated with the freeze frame data is erased or the DTCs are cleared, new freeze frame data can be stored again. In the event of multiple emission related DTCs in memory, always note the DTC for the freeze frame data.
| Acronym | Description | Measurement Units |
|---|---|---|
| APP_D | Accelerator Pedal Position D | % |
| APP_E | Accelerator Pedal Position E | % |
| BARO | Barometric Pressure | KPa |
| CATTEMP11 | Catalyst Temperature Bank 1, Sensor 1 | Degrees |
| CATTEMP21 | Catalyst Temperature Bank 2, Sensor 1 | Degrees |
| CLRDIST | Distance Since Codes Cleared | Km/mi |
| ECT | Engine Coolant Temperature | Degrees |
| EQ_RAT | Commanded Equivalence Ratio | Unit |
| EQ_RAT11 | Lambda Value Bank 1, Sensor 1 | Unit |
| EQ_RAT21 | Lambda Value Bank 2, Sensor 1 | Unit |
| EVAPPCT | Commanded Evaporative Purge | % |
| FLI | Fuel Level Input | % |
| FRP | Fuel Rail Pressure | KPa |
| FUELSYS1 | Open/Closed Loop 1 | OL/CL/OL DRIVE/OL FAULT/CL FAULT |
| FUELSYS2 | Open/Closed Loop 2 | OL/CL/OL DRIVE/OL FAULT/CL FAULT |
| IAT | Intake Air Temperature | Degrees |
| LFT1 | Long Term Fuel Bank 1 | % |
| LFT2 | Long Term Fuel Bank 2 | % |
| LOAD | Calculated Load Value | % |
| MAF | Mass Airflow Rate | G/s |
| MAP | Manifold Absolute Pressure | Volts/kPa/ PSI/in-Hg |
| O2S11 | Bank 1 Upstream Oxygen Sensor (11) | Volts/mA |
| O2S12 | Bank 1 Downstream Oxygen Sensor (12) | Volts |
| O2S21 | Bank 2 Upstream Oxygen Sensor (21) | Volts/mA |
| O2S22 | Bank 2 Downstream Oxygen Sensor (22) | Volts |
| RPM | Engine RPM | RPM |
| RUNTM | Run Time | Seconds |
| SFT1 | Short Term Fuel Bank 1 | % |
| SFT2 | Short Term Fuel Bank 2 | % |
| SPARKADV | Spark Advance | Degrees |
| TAC_PCT | Commanded Throttle Actuator | % |
| TP | Absolute Throttle Position | % |
| TP_REL | Relative Throttle Position | % |
| VS | Vehicle Speed | Km/h-mph |
| WARMUPS | Number Of Warmups Since Code Cleared | Units |
FREEZE FRAME DATA
Some unique PIDs are stored in the keep alive memory (KAM) of the PCM to help in diagnosing the root cause of misfires. These PIDs are collectively called misfire freeze frame (MFF) data. These parameters are separate from the generic freeze frame data stored for every MIL code and are used for misfire diagnosis only. The MFF data could be more useful for misfire diagnosis than the generic freeze frame data. It is captured at the time of the highest misfire rate, not when the DTC is stored at the end of a 200 or 1, 000 revolution block (generic freeze frame data for misfire can be stored minutes after the misfire actually occurred).
The MFF PIDs are supported on all vehicles, but may not be available on all scan tools because enhanced PID access may vary by scan tool manufacturer.
| PID Name | Description | Measurement Units |
|---|---|---|
| MFF_EGR | EGR DPFE Sensor At The Time Of Misfire | Volts |
| MFF_IAT | Intake Air Temperature At The Time Of Misfire | Degrees |
| MFF_INGEAR | Transmission In Gear At The Time Of Misfire | Yes/No |
| MFF_LOAD | Engine Load At The Time Of Misfire | % |
| MFF_PNP | Park/Neutral Position At The Time Of Misfire | Mode |
| MFF_RNTM | Engine Running Time At The Time Of Misfire | Time |
| MFF_RPM | Engine RPM At The Time Of Misfire | RPM |
| MFF_RUN | Engine Running Time At The Time Of Misfire | Time |
| MFF_SOAK | Engine Off Soak Time At The Time Of Misfire | Time |
| MFF_TCC_LOCK | Torque Converter Clutch At The Time Of Misfire | Yes/No |
| MFF_THR_ANG | Throttle Angle At The Time Of Misfire | % |
| MFF_TP | Throttle Position At The Time Of Misfire | Volts |
| MFF_TRIP | Number Of Driving Cycles At The Time Of Misfire (At Least One 1, 000 Rev Block) | Number of Trips |
| MFF_VSS | Vehicle Speed At The Time Of Misfire | Km/h-mph |
| MP_ LRN | Learned Misfire Correction Profile | Yes/No |
MISFIRE FREEZE FRAME PIDS
Manufacturer Specific Freeze Frame
The manufacturer specific freeze frame data is DTC snapshot data that allows a manufacturer to store vehicle condition information when a DTC sets. This is similar to the OBDII freeze frame functionality that already exists in the PCM. The manufacturer defines the snapshot data to provide the conditions at the time when a fault occurred. Each snapshot is about 40 - 50 PIDs with up to 5 snapshots available for up to 5 different DTCs. The PCM reports the most recent fault conditions for the DTC, and refreshes a maximum of once per operation cycle.
| PID Name | Description | Measurement Units |
|---|---|---|
| APP1 | Accelerator Pedal Position 1 | Volts |
| APP2 | Accelerator Pedal Position 2 | Volts |
| APP_FLT | Accelerator Pedal Position Status | Fault/No Fault |
| BARO | Barometric Pressure | Pressure/in H20 |
| CHT_F | Cylinder Head Temperature Status | Fault/No Fault |
| CHTIL | Cylinder Head Temperature Indicator | Lamp On/Off |
| ECT | Engine Coolant Temperature | Degrees |
| ECT_F | Engine Coolant Temperature Status | Fault/No Fault |
| EGR_F | Exhaust Gas Recirculation Status | Fault/No Fault |
| EGRPCT | Commanded EGR | Percent |
| ETC [TAC_PCT] | Commanded Throttle Actuator Control | Percent |
| ETC_TRIM_LRN | Throttle Angle Trim Value Has Learned | Yes/No |
| FF_LRND | Flex Fuel Learned | Yes/No |
| FLI | Fuel Level | Percent |
| FTP_H2O | Fuel Tank Pressure Input | Pressure |
| FUELSYS | Fuel System Status | Open Loop/Closed Loop |
| GEAR | Transmission Gear Status | Gear |
| IAT | Intake Air Temperature | Degrees |
| IAT_F | Inlet Air Temperature Status | Fault/No Fault |
| LOAD | Calculated Engine Load | Percent |
| LONGFT1 | Long Term Fuel Trim Bank 1 | Percent |
| LONGFT2 | Long Term Fuel Trim Bank 2 | Percent |
| MAF | Mass Airflow Rate | G/s |
| MAF_F | Mass Airflow Status | Fault/No Fault |
| MAP | Manifold Absolute Pressure | KPa/PSI/in-Hg |
| MAP_F | Manifold Absolute Pressure Sensor Status | Fault/No Fault |
| MISFIRE | Misfire Malfunction Detection | Yes/No |
| MP_LRN | Learned Misfire Correction Profile | Yes/No |
| O2S11 | Bank 1 Upstream Oxygen Sensor (11) | Volts |
| O2S12 | Bank 1 Downstream Oxygen Sensor (12) | Volts |
| O2S21 | Bank 2 Upstream Oxygen Sensor (21) | Volts |
| O2S22 | Bank 2 Downstream Oxygen Sensor (22) | Volts |
| OSS_SRC | Output Shaft Speed | RPM |
| RPM | Engine RPM | RPM |
| RPMDSD | RPM Desired | RPM |
| RUNTM | Run Time | Seconds |
| SHRTFT1 | Short Term Fuel Trim Bank 1 | Percent |
| SPARKADV | Spark Advance | Degrees |
| TCC | Torque Converter Clutch | Percent |
| TP1 | Throttle Position 1 Voltage | Volts |
| TP2 | Throttle Position 2 Voltage | Volts |
| TP_F | Throttle Position Sensor Status | Fault/No Fault |
| TP_REL | Relative Throttle Position | % |
| TQ_CNTRL | Torque Fuel Spark Limiting Status | Status |
| VPWR | Vehicle Power Voltage | Volts |
MANUFACTURER SPECIFIC FREEZE FRAME PIDS
Neutral Profile Correction
In order for the misfire detection system to function correctly, any mechanical inaccuracies in the crankshaft position (CKP) sensor must be learned by the PCM. This information is stored in non-volatile memory (NVM) in the PCM. It is not cleared when the keep alive memory (KAM) is reset.
Neutral profile learning is accomplished using the scan tool any time a PCM is replaced. It should also be relearned any time the CKP sensor or the crankshaft pulse wheel is replaced or major engine repairs have been completed.
To determine if the neutral profile learning has been completed, check the MP_LRN parameter identification (PID) using the scan tool. The PID should read YES if the neutral profile learning has been completed. If the PID reads NO, complete the neutral profile learning prior to diagnosing any misfire DTCs.
Making Changes to the VID Block
A programmed PCM may require changes to be made to certain VID information to accommodate the vehicle hardware. Refer to Module Reprogramming on the scan tool.
Drive Cycle Recommendations
| WARNING | STRICT OBSERVANCE OF POSTED SPEED LIMITS AND ATTENTION TO DRIVING CONDITIONS ARE MANDATORY WHEN PROCEEDING THROUGH THE FOLLOWING DRIVE CYCLES. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY. |
- Most OBD monitors complete more readily using a steady foot driving style during cruise or acceleration modes. Operating the throttle in a smooth fashion minimizes the time required for monitor completion.
- The fuel tank level should be between 1/2 and 3/4 full with 3/4 full being the most desirable.
- The evaporative monitor can operate only during the first 30 minutes of engine operation. When executing the procedure for this monitor, stay in part throttle mode and drive in a smooth fashion to minimize fuel slosh.
- When bypassing the EVAP engine soak times, the PCM must remain powered (ignition ON) after clearing the continuous DTCs and relearning emission diagnostic information.
For best results, follow each of the following steps as accurately as possible
| OBD Monitor Exercised | Drive Cycle Procedure | Purpose of Drive Cycle Procedure |
|---|---|---|
| Drive Cycle Preparation | NOTE: To bypass the EVAP soak timer (normally 6 hours), the PCM must remain powered after clearing the continuous DTCs and resetting the emission monitors information in the PCM. 1. Install the scan tool. Turn the ignition ON with the engine OFF. Cycle the ignition OFF, then ON. If needed, select the appropriate vehicle and engine qualifier. Clear the continuous DTCs and reset the emission monitors information in the PCM. | Bypasses the engine soak timer. Resets the OBD monitor status. |
| 2. Begin to monitor the following PIDs (if available): AAT, ECT, EVAPDC, FLI, IAT and TP MODE. Start the vehicle without returning the ignition to the OFF position. 3. Idle the vehicle for 15 seconds. Drive at 77 to 104 km/h (48 to 65 mph) until the engine coolant temperature (ECT) is at least 76.7°C (170°F). | ||
| Prep for Monitor Entry | 4. Is the intake air temperature (IAT) between 4.4 and 37.8°C (40 and 100°F)? If not, complete the following steps, but note that step 14 is required to bypass the EVAP monitor and complete the OBD drive cycle. | Engine warm-up and provides intake air temperature input to the PCM. |
| HO2S | 5. Cruise at 77 to 104 km/h (48 to 65 mph) for greater than 5 minutes. | Executes the HO2S monitor. |
| EVAP | 6. Cruise at 77 to 104 km/h (48 to 65 mph) for 10 minutes (avoid sharp turns and hills). NOTE: To initiate the monitor, the throttle should be at part throttle, EVAPDC must be greater than 75%, and FLI must be between 15 and 85%, and for fuel tanks over 25 gallons FLI must be between 30 and 85%. | Executes the EVAP monitor if the intake air temperature is between 4.4 to 37.8°C (40 to 100°F). |
| Catalyst | 7. Drive in stop and go traffic conditions. Include 5 different constant cruise speeds, ranging from 40 to 72 km/h (25 to 45 mph) over a 10 minute period. | Executes the catalyst monitor. |
| EGR | 8. From a stop, idle for 30 seconds, accelerate to 72 km/h (45 mph) at 1/2 to 3/4 throttle, cruise at steady throttle for 1 minute. Repeat idle, acceleration and cruise 3 times. | Executes the exhaust gas recirculation (EGR) monitor. |
| CCM (Engine) | 9. Bring the vehicle to a stop. Idle with the transmission in drive (neutral for M/T) for 2 minutes. | Executes the idle air control portion of the comprehensive component monitor (CCM). |
| CCM (Transmission) | 10. For M/T, accelerate from 0 to 80 km/h (0 to 50 mph), and continue to step 11. For A/T, from a stop and in overdrive, moderately accelerate to 80 km/h (50 mph) and cruise for greater than 15 seconds. Stop the vehicle and repeat without overdrive to 64 km/h (40 mph) cruising for greater than 30 seconds. While at 64 km/h (40 mph), activate the overdrive, accelerate to 80 km/h (50 mph) and cruise for greater than 15 seconds. Stop for at least 20 seconds and repeat step 10 five times. | Executes the transmission portion of the CCM. |
| Misfire, Fuel And Deceleration Fuel Shut Off Rear HO2S Monitors | 11. From a stop, accelerate to 104 km/h (65 mph), hold steady throttle for 5 seconds, then decelerate at closed throttle to 64 km/h (40 mph) (no brakes), accelerate from 64 km/h (40 mph) to 104 km/h (65 mph), hold steady throttle for 5 seconds, repeat deceleration 5 times. | Allows learning for the misfire monitor, and completion of the deceleration fuel shut off rear HO2S monitor. |
| Readiness Check | 12. Access the On Board System Readiness (OBD monitor status) function on the scan tool. Determine whether all non-continuous monitors have completed. If not, go to step 13. | Determines if any monitor has not completed. |
| Pending Code Check And EVAP Monitor Bypass Check | 13. With the scan tool, check for pending codes. Conduct the normal repair procedures for any pending code concern. Otherwise, repeat any incomplete monitor. If the EVAP monitor is not complete and the intake air temperature (IAT) was out of the 4.4 to 37.8°C (40 to 100°F) temperature range in step 4, or the altitude is over 2438 m (8000 ft.), the EVAP bypass procedure must be followed. Go to Step 14. | Determines if a pending code is preventing the completion of the OBD drive cycle. |
| EVAP Monitor Bypass | 14. Park the vehicle for a minimum of 8 hours. Repeat steps 2 through 11. Do not repeat step 1. | Allows the bypass counter to increment to 2. |
| NOTE |
|---|
| To bypass the EVAP soak timer (normally 6 hours), the PCM must remain powered after clearing the continuous DTCs and resetting the emission monitors information in the PCM. |
Recreating the Fault
Recreating the concern is the first step in isolating the cause of the intermittent symptom. A thorough investigation should start with the customer information worksheet . If freeze frame data is available, it may help in recreating the conditions at the time of a malfunction indicator lamp diagnostic trouble code (MIL DTC). Listed below are some of the conditions for recreating the concern
| Engine Type Conditions | Non-Engine Type Conditions |
|---|---|
| Engine Temperature | Ambient Temperature |
| Engine RPM | Moisture Conditions |
| Engine Load | Road Conditions (Smooth-Bumpy) |
| Engine Idle/Accel/Deceleration |
CONDITIONS TO RECREATE FAULT
Accumulating PCM Data
PCM data can be accumulated in a number of ways. This includes circuit measurements with a digital multimeter (DMM) or scan tool parameter identification (PID) data. Acquisition of PCM PID data using a scan tool is one of the easiest ways to gather information. Gather as much data as possible when the concern is occurring to prevent improper diagnosis. Data should be accumulated during different operating conditions and based on the customer description of the intermittent concern. Compare this data with the known good data values. Refer to TYPICAL DIAGNOSTIC REFERENCE VALUES . This requires recording data in four conditions for comparison: 1) KOEO, 2) Hot Idle, 3) 48 km/h (30 mph), and 4) 89 km/h (55 mph).
Peripheral Inputs
Some signals may require certain peripherals or auxiliary tools for diagnosis. In some cases, these devices can be inserted into the measurement jacks of the scan tool or DMM. For example, connecting an electronic fuel pressure gauge to monitor and record the fuel pressure voltage reading and capturing the data would help find the fault.
Comparing PCM Data
After the PCM values are acquired, it is necessary to determine the concern area. This typically requires the comparison of the actual values from the vehicle to the typical values . Refer to TYPICAL DIAGNOSTIC REFERENCE VALUES . The charts apply to different vehicle applications (engine, model, transmission).
Analyzing PCM Data
Look for abnormal events or values that are clearly incorrect. Inspect the signals for abrupt or unexpected changes. For example, during a steady cruise most of the sensor values should be relatively stable. Sensors such as throttle position (TP) and mass airflow (MAF), as well as an RPM that changes abruptly when the vehicle is traveling at a constant speed, are clues to a possible concern area.
Look for an agreement in related signals. For example, if the APP1 or APP2 changes during acceleration, a corresponding change should occur in RPM and SPARK ADV PID.
Make sure the signals act in proper sequence. An increase in RPM after the TP1 and TP2 increases is expected. If the RPM increases without a TP1 and TP2 change, a concern may exist.
The PID values are not always captured from the same execution loop. Depending on the number of PIDs acquired, the sample rate may be 60 ms or longer. For example, the ETC_ACT reading will always lag behind the ETC_DSD reading due to the physical time to move the throttle plate. This is an expected difference between ETC_ACT and ETC_DSD during these events.
Scroll through the PID data while analyzing the information. Look for sudden drops or spikes in the values.
Obtain Freeze Frame Data
Freeze frame data is helpful in duplicating and diagnosing adaptive fuel concerns. The data (a snapshot of certain PID values recorded at the time the DTC is stored in continuous memory) is helpful to determine how the vehicle was being driven when the concern occurred, and is especially useful on intermittent concerns. Freeze frame data, in many cases, helps isolate possible areas of concern as well as rule out others. Refer to FREEZE FRAME DATA for a more detailed description of this data.
Using the LONGFT1 and LONGFT2 (Dual Bank Engines) PIDs
The LONGFT1 and LONGFT2 PIDs are useful for diagnosing fuel trim concerns. A negative PID value indicates fuel is being reduced to compensate for a rich condition. A positive PID value indicates fuel is being increased to compensate for a lean condition. It is important to know there is a separate LONGFT value used for each RPM and load point of engine operation. When viewing the LONGFT1 and LONGFT2 PIDs, the values may change a great deal as the engine is operating at different RPM and load points. This is because the fuel system may have learned corrections for fuel delivery concerns that can change as a function of engine RPM and load. The LONGFT1 and LONGFT2 PIDs display the fuel trim currently being used at that RPM and load point. Observing the changes in LONGFT1 and LONGFT2 can help when diagnosing fuel system concerns. For example
- A contaminated mass airflow (MAF) sensor results in matching LONGFT1 and LONGFT2 correction values that are negative at idle (reducing fuel), but positive (adding fuel) at higher RPM and loads.
- LONGFT1 values that differ greatly from LONGFT2 values rule out concerns that are common for both banks (for example, fuel pressure concerns, MAF sensor, etc. can be ruled out).
- Vacuum leaks result in large rich corrections (positive LONGFT1 and LONGFT2 values) at idle, but little or no correction at higher RPM and loads.
- A plugged fuel filter results in no correction at idle, but large rich corrections (positive LONGFT1 and LONGFT2 values) at high RPM and load.
Air Measurement System
With this condition, the engine runs rich or lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition.
For example, the MAF sensor measurement is inaccurate due to a corroded connector, contaminated or dirty connector. A contaminated MAF sensor typically results in a rich system at low airflows (PCM reduces fuel) and a lean system at high airflows (PCM increases fuel).
Vacuum Leaks and Unmetered Air
With this condition, the engine may actually run lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition. This condition can be caused by unmetered air entering the engine. Vacuum leaks normally are most apparent when high manifold vacuum is present (for example, during idle or light throttle). If freeze frame data indicates the fault occurred at idle, a check for vacuum leaks and unmetered air might be the best starting point.
For example, loose, leaking or disconnected vacuum lines, intake manifold gaskets or O-rings, throttle body gaskets, brake booster, air inlet tube or unseated engine oil dipstick.
Insufficient Fueling
With this condition, the engine runs lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition. This condition is caused by a fuel delivery system concern that restricts or limits the amount of fuel being delivered to the engine. This condition is normally apparent as the engine is under a heavy load and at high RPM, when a higher volume of fuel is required. If the freeze frame data indicates the concern occurs under a heavy load and at higher RPM, a check of the fuel delivery system (checking fuel pressure with engine under a load) is the best starting point.
Examples of this include
- low fuel pressure (fuel pump, fuel filter, fuel leaks, restricted fuel supply lines)
- fuel injector concerns
Exhaust System Leaks
In this type of condition, the engine runs rich of stoichiometry (14.7:1 air to fuel ratio) because the fuel control system is adding fuel to compensate for a perceived (not actual) lean condition. This condition is caused by the heated oxygen sensor (HO2S) sensing the oxygen (air) entering the exhaust system from an external source. The PCM reacts to this exhaust leak by increasing fuel delivery. This condition causes the exhaust gas mixture from the cylinder to be rich.
Examples of this include
- exhaust system leaks upstream or near the HO2S
- cracked or leaking HO2S boss
With this condition, the engine runs rich or lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition.
Fuel System
With this condition, the engine runs rich of stoichiometry (14.7:1 air to fuel ratio), if the PCM is not able to compensate enough to correct for the condition. This situation causes a fuel delivery system that is delivering excessive fuel to the engine.
Examples of this include
- fuel pressure regulator (mechanical returnless fuel systems) causes excessive fuel pressure (system rich at all airflows), fuel pressure is intermittent, going to pump deadhead pressure, then returning to normal after the engine is turned off and restarted.
- fuel injector leaks (injector delivers extra fuel).
- evaporative emission (EVAP) purge valve leak (introduces extra fuel).
- fuel rail pressure (FRP) sensor (electronic returnless fuel systems) concern causes the sensor to indicate a lower pressure than actual. The PCM commands a higher duty cycle to the fuel pump control module, causing high fuel pressure (system rich at all airflows).
Intake Air System
A restriction within any of the intake air system components may be significant enough to affect the ability of the PCM adaptive fuel control.
Base Engine
Engine oil contaminated with fuel can contribute to a rich running engine.