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Engine Controls - Diagnostic Methods - (Hybrid): Other Mercury Mariner II

Testing & Diagnostics ~2000 words

Vehicle Check/Preparation

Before using the scan tool to carry out any test, refer to the Important Safety Notice located in the Introduction of this article and the necessary visual checks listed below.

Visual Checks

WARNINGThis vehicle is equipped with high voltage cables, components, and wiring. The high voltage warning labels containing the high voltage symbol are located on each high voltage component. High voltage cables and wiring are orange in color. Certified rubber insulating gloves and a face shield must be worn when working with the high voltage cables, components, or wiring. The ignition key must be cycled to the OFF position for a minimum of 5 minutes, and the high voltage traction battery service disconnect plug placed in the servicing/shipping position before disconnecting the high voltage cables. Do not disconnect, disable, or touch the high voltage cables, components, or wiring during the module reprogramming procedure because high voltage is present. Failure to follow these instructions may result in personal injury or death.
  1. Inspect the air cleaner and inlet duct.
  2. Check all engine vacuum hoses for damage, leaks, cracks, kinks and proper routing.
  3. Check the powertrain control module (PCM) or transaxle control module (TCM) wiring harness for proper connections, bent or broken pins, corrosion, loose wires and proper routing.
  4. Examine all high voltage cables and connectors for secure connection, damaged, burned or overheated insulation and loose or broken condition.
  5. Verify the traction battery high voltage service plug is properly connected.
  6. Verify the front and rear inertia fuel shutoff (IFS) switches are not tripped.
  7. Check the PCM, sensors, and actuators for physical damage.
  8. Check the engine coolant for proper level and mixture.
  9. Check the motor electronics coolant for proper level and mixture.
  10. Check the transaxle fluid level and quality. Refer to the «AUTOMATIC TRANSAXLE/TRANSMISSION EXTERNAL CONTROLS - HYBRID»(ref-292247) .
  11. Make all necessary repairs before continuing with the quick test.

Vehicle Preparation

  1. Carry out all safety steps required to start and run vehicle tests. Apply the parking brake, place the gear selector firmly into the PARK position and block the drive wheels.
  2. Verify the high voltage traction battery state of charge is equal to or greater than 45% by monitoring the traction battery control module (TBCM) state of charge parameter identification (PID). If the monitored PID displays the state of charge below 45%, start and idle the engine with full A/C ON.
  3. Turn the A/C on and verify it functions correctly.
  4. Turn off all electrical loads, such as radios, lamps, A/C, blower, and fans.
  5. Start the engine and bring it up to the normal operating temperature before running the quick test.

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 FrameAcronymDescriptionMeasurement Units
AIRSecondary Air StatusOn/Off
CCNTContinuous DTC CounterDecimal
XECTEngine Coolant TemperatureDegrees
XFUEL SYS1Fuel System Feedback Control Status-Bank 1OL/CL/OL DRIVE a /OL FAULT/CL FAULT
IATIntake Air TemperatureDegrees
XLOAD bCalculated Engine Load%
XLONG FT1Current Bank 1 fuel trim adjustment from stoichiometric which is considered long term.%
MAFMass Air Flow RateGm/s-lb/min
O2S11Bank 1 Upstream Oxygen Sensor (11)Volts
O2S12Bank 1 Downstream Oxygen Sensor (12)Volts
OBD SUPOn-Board Diagnostic SystemOBD II OBD I OBD Combination of or None
PTOPower Take-Off StatusOn/Off
XRPMRevolutions per MinuteRPM
XSHRT FT1Current bank fuel trim adjustment from stoichiometric which is considered short term.%
SHRT FT11 cCurrent bank fuel trim adjustment from stoichiometric which is considered short term.%
SHRT FT12 cCurrent bank 1 fuel trim adjustment from stoichiometric which is considered short term.%
SPARKADVSpark Advance Cylinder No. 1Degrees
TPThrottle Position%
XVSSVehicle Speed SensorKm/h-mph
CL = Closed loop using HO2S(s) as feedback for fuel control. OL DRIVE = Open loop due to driving conditions (heavy acceleration). OL FAULT = Open loop due to fault with all upstream HO2S sensors. CL FAULT = Closed loop fuel control, but fault with 1 upstream HO2S sensor.

a OL = Open loop, has not satisfied conditions for closed loop.

b Percent engine load adjusted for atmospheric pressure.

c Individual oxygen sensor fuel trim adjustment is not supported.

Ford PCM PID List

AcronymDescriptionFord Units
ACCSA/C Cycling SwitchYES/NO
ACPA/C Head Pressure Switch InputOPEN/CLOSED
ACRDVA/C Refrigerant Distribution Valve OutputON/OFF
ACRDV_FA/C Refrigerant Distribution Valve Output FaultYES/NO
A/CTA/C Evaporator Temperature InputDEGREES
APPAccelerator Pedal PositionPERCENT
APP1Accelerator Pedal Position 1VOLTS
APP2Accelerator Pedal Position 2VOLTS
APP3Accelerator Pedal Position 3VOLTS
BAROBarometric Pressure (software determined)In-Hg
BPOBattery Power Off ReceivedYES/NO
BPO_HzBattery Power Off InputFREQUENCY
BPP/BOOBrake Pedal Position/Brake On-Off Switch InputON/OFF
CCNTNumber of Stored and Pending DTCsDECIMAL
CHTCylinder Head Temperature InputDEGREES
CHTVCylinder Head Temperature InputVOLTS
CMPFMCamshaft Position Sensor Fault ModeYES/NO
CRK_TTime since engine startedSEC
DRIVECNTNumber of completed OBD Drive CyclesDECIMAL
DCEDC/DC Converter Enable CommandedON/OFF
DCE_FDC/DC Converter Enable FaultYES/NO
DEL_MOD_VDelta Mode VoltageDCV
ECTEngine Coolant Temperature InputDEGREES
ECT_VEngine Coolant Temperature InputVOLTS
EGRMC1EGR Motor Control Output CommandON/OFF
EGRMC1FEGR Motor Control Output FaultYES/NO
EGRMC2EGR Motor Control Output CommandON/OFF
EGRMC2FEGR Motor Control Output FaultYES/NO
EGRMC3EGR Motor Control Output CommandON/OFF
EGRMC3FEGR Motor Control Output FaultYES/NO
EGRMC4EGR Motor Control Output CommandON/OFF
EGRMC4FEGR Motor Control Output FaultYES/NO
EGRMDSDEGR Motor Position DesiredSTEP
ENG_TQEngine TorqueNm
ENGRMPAEngine RPMRPM
ETC_ACTElectronic Throttle Control ActualDEGREES
ETC_DSDElectronic Throttle Control DesiredDEGREES
EVAPCVEvaporative Emissions Canister Purge Vent Control%
EVAPCV_FEvaporative Emissions Canister Purge Vent FaultYES/NO
EVAPVMAEvaporative Vapor Management Valve Internal Circuit MonitorVOLTS
EVMVElectronic Vapor Management Valve ControlMA
FANSSFan Speed SensorRPM
FLIFuel Level Indicator Input%
FPFuel Pump Duty Cycle%
FRPFuel Rail Pressure InputDCV/kPa/psi
FRP_DSDFuel Rail Pressure DesiredPSI
FRTMPABFuel Rail Temperature - Bank 1 InputDEGREES
FRTFuel Rail Temperature VoltageVOLTS
FTPFuel Tank Pressure InputKPa/DCV
FTP_H2OFuel Tank Pressure H2OIn H2O
FUELPW1Injector Pulse Width Bank 1MILLISECONDS
G_SDNGenerator Motor Shutdown RequestYES/NO
G_SPEEDGenerator SpeedRPM
GTQMeasured Generator Motor TorqueNM
HFCHigh Speed Fan ControlON/OFF
HFCFHigh Speed Fan Control FaultYES/NO
HFPIPPIP up edge to PIP down edge timeSEC
HTRCM11Bank 1 Sensor 1 HO2S Heater ControlAMPS
HTRCM12Bank 1 Sensor 2 HO2S Heater ControlMA
HPUMPHeater Pump OutputON/OFF
HPUMP_FHeater Pump Output FaultYES/NO
IATIntake Air Temperature InputDEGREES
IAT_FIntake Air Temperature FaultYES/NO
IGN_OFFIgnition Switch Position OFF InputYES/NO
INJ1_FInjector 1 Commanded FaultYES/NO
INJ2_FInjector 2 Commanded FaultYES/NO
INJ3_FInjector 3 Commanded FaultYES/NO
INJ4_FInjector 4 Commanded FaultYES/NO
INJ_TIMInjector Timing Before Top Dead CenterDEGREES
KEYSTKey StateKEY POSITION
LFCLow Speed Fan ControlON/OFF
LFCFLow Speed Fan Control FaultYES/NO
LOADCalculated Engine Load%
LONGFT1Long Term Fuel Trim Bank 1%
LOSSTRTLimited Operating Strategy (Related To Engine No Start)YES/NO
LOS_BRKLimited Operating Strategy (Related To Regenerative Braking)YES/NO
LOS_ENGLimited Operating Strategy (Related To Engine)YES/NO
LOS_ETCLimited Operating Strategy (Related To ETC System)YES/NO
LOS_EQLimited Operating Strategy (Related To E-Quizzer)YES/NO
LOS_GENLimited Operating Strategy (Related To Generator Motor)YES/NO
LOS_HVLimited Operating Strategy (Related To Traction Battery)YES/NO
LOS_IPCLimited Operating Strategy (Related To Independent Plausibility Checker)YES/NO
LOS_KEYLimited Operating Strategy (Related To Key Position)YES/NO
LOS_LVLimited Operating Strategy (Related To Low Voltage Battery)YES/NO
LOS_MOTLimited Operating Strategy (Related To Traction Motor)YES/NO
LOS_TCMLimited Operating Strategy (Related To Transaxle)YES/NO
MAFMass Airflow Rate InputGM/S/DCV
MAF_FMass Airflow Sensor FaultYES/NO
MAPManifold Absolute Pressure Sensor VoltageDCV/kPa/PSI
MAP_FManifold Absolute Pressure Sensor FaultYES/NO
MECT_VMotor Electronics Coolant Temperature InputVOLTS
MECPMotor Electronics Coolant Pump CommandedON/OFF
MECP_FMotor Electronics Coolant Pump FaultYES/NO
MFC_FMedium Speed Fan Control FaultYES/NO
MILMalfunction Indicator Lamp ControlON/OFF
MTQMeasured Traction Motor TorqueNM
M_SDNTraction Motor Shutdown RequestYES/NO
O2S11Bank 1, Sensor 1 InputVOLTS
O2S12Bank 1, Sensor 2 InputVOLTS
PIP_CTRPIP CounterDECIMAL
PIPTIMLast PIP TimeSEC
PSRPower Sustain Relay CommandedON/OFF
RPMEngine Speed Calculated From CKP SignalRPM
RPM_DSDDesired Engine SpeedRPM
SPARKADVSpark AdvanceDEGREES
TP1Throttle Position 1 VoltageVOLTS
TP2Throttle Position 2 VoltageVOLTS
TP_MODEThrottle Position ModeC/T, P/T, WOT
TPRELLowest Steady TP Voltage Since Engine StartVOLTS
TRGear Position Indicated By Transmission Range SensorGEAR
TR_A1Analog Transmission Range Sensor 1 InputVOLTS
TR_A2Analog Transmission Range Sensor 2 InputVOLTS
TR_A3Analog Transmission Range Sensor 3 InputVOLTS
TRIPCNTNumber of Completed OBD TripsDECIMAL
VPWRVehicle Power VoltageVOLTS
VREFVehicle Reference VoltageVOLTS
VSSVehicle SpeedMPH
WAC/ACCRA/C Clutch CommandON/OFF

Ford TCM PID List

AcronymDescriptionManufacturer Units
ABS_STATABS System Status TCM ReceivedACTIVATED/NOT ACTIVATED
ACCESSAccess StatusTime
ARPMDESDesired Engine Speed TCM ReceivedRPM
CCNTNumber Of Continuous DTCs Stored In TCMDECIMAL
ENG CTOVehicle Speed TCM ReceivedRPM
CONTACTTraction Battery Contractor Status TCM ReceivedOPEN/CLOSED
ENABL_SEnable StatusDisable/Enable
GCLTEMPGenerator Motor Coil TemperatureDEGREES
GENMODEGenerator Operational Mode TCM ReceivedMODE
GTQ_CMDMeasured Generator Motor TorqueNm
GTQ_OUTDesired Generator Motor Torque TCM ReceivedNm
G_INV_VActual Generator Motor Inverter VoltageVOLTS
G_PHTEMPGenerator Motor Inverter Temperature (Highest of 3 Phases)DEGREES
G_SDN_AGenerator Motor Shutdown TCM ReceivedON/OFF
G_SDN_CGenerator Motor Shutdown TCM ReceivedON/OFF
G_SPEEDGenerator Motor SpeedRPM
HV_AMPTraction Battery Current TCM Received Through Communication NetworkAMPERES
HVBAT_VTraction Battery Voltage TCM ReceivedVOLTS
HVINTLCKHigh Voltage Interlock Circuit StatusON/OFF
I_SDN_1Immediate Shutdown 1 InputCHARGE/ DISCHARGE
I_SDN_2Immediate Shutdown 2 InputCHARGE/ DISCHARGE
LF_WSPDFront Left Wheel SpeedKm/h/MPH
MCLTEMPTraction Motor Coil TemperatureDEGREES
MECTMotor Electronics Coolant Temperature TCM ReceivedDEGREES
MIN#KEYMinimum Number of Keys#
MIL_KEYMaster KeyYES/NO
M_SDN_ATraction Motor Shutdown TCM ReceivedON/OFF
M_SDN_CTraction Motor Shutdown TCM ReceivedON/OFF
MTQ_CMDDesired Traction Motor Torque TCM ReceivedNm
MTQ_OUTMeasured Traction Motor TorqueNm
M_INV_VActual Traction Motor Inverter VoltageVOLTS
M_PHTEMPTraction Motor Inverter Temperature (Highest of 3 Phases)DEGREES
M_SPEEDTraction Motor SpeedRPM
PCM IDPCM IdentifiedNot Stored/Stored
PCM_VFYPCM VerifyYES/NO
PRNDL_TGear selector position TCM receivedSELECTOR POSITION
RF_WSPDFront Right Wheel SpeedKm/h/MPH
RPMEngine Speed TCM CalculatedRPM
SERMODService ModeMode
TCM_CAUPowertrain Malfunction Indicator (Wrench) CommandedON/OFF
TCM_HAZHazard Indicator CommandedON/OFF
TFTTransaxle Fluid Temperature InputDEGREES
TORQUEEngine Torque TCM ReceivedLB-FT
TQ_DSDDesired Torque TCM ReceivedNM
UNL_KEYUnlimited Keys#
VBATVehicle Power VoltageVOLTS
VEHMODEVehicle Operational Mode TCM ReceivedMODE
VSSVehicle Speed TCM CalculatedKm/h

Freeze frame data allows access to emission-related values from specific generic parameter identifications (PIDs). 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 1 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.

AcronymDescriptionMeasurement Units
ECTEngine Coolant TemperatureDegrees
FUELSYS1Open/Closed Loop1OL/CL/OL DRIVE/OL FAULT/CL FAULT
LONGFT1Long Term Fuel Bank1%
LOADCalculated Load Value%
RPMEngine RPMRPM
SHRTFT1Short Term Fuel Bank1%
VSSVehicle SpeedKm/h-mph

FREEZE FRAME DATA TABLE

Some unique PIDs are stored in the keep alive memory (KAM) of the powertrain control module (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 that is stored for every malfunction indicator lamp (MIL) code. They are used for misfire diagnosis only. The MFF data is more useful for misfire diagnosis than the normal diagnosis only. It is captured at the time of the highest misfire rate and not when the DTC is stored at the end of a 1,000 or 200 revolution block. (Generic freeze-frame data for misfire can be stored minutes after the misfire actually occurred.)

Note. The MFF frame 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 NameDescriptionMeasurement Units
MFF RPMEngine RPM at the time of misfireRPM
MFF LOADEngine load at the time of misfirePERCENT
MFF VSVehicle speed at the time of misfireMPH/KPH
MFF IATIntake air temperature at the time of misfireDEGREES
MFF SOAKEngine-off soak time at the time of misfireMINUTES
MFF RNTMEngine running time at the time of misfireSECONDS
MFF TPThrottle position at time of misfireVOLTAGE
MFF T CNTNumber of driving cycles at the time of misfire (at least one 1,000 rev block)Number of TRIPS
MFF PNP1= in drive during the time of misfireMODE
MP LRN1= misfire wheel profile learned in KAMNONE

MISFIRE FREEZE FRAME PIDS

Freeze frame data allows access to non-emission related values from specific manufacturers PIDs. These values are stored when a non-emission related DTC is stored in continuous memory. This provides a snapshot of the conditions that were present when the DTC was stored. Once 1 set of freeze frame data is stored, this data remains in memory even if another DTC is stored. When a DTC associated with the freeze frame data is cleared or a KAM reset is carried out, new freeze frame data can be stored again.

AcronymDescriptionMeasurement Units
FRZ_DTCFrozen DTC detailed numberDecimal
RPMEngine speedRPM
TFTTransaxle fluid temperatureDegrees
M_SPEEDTraction motor speedRPM
G_INV_VGenerator inverter voltageVolts
M_PHTMPThe highest traction motor inverter temperature within the 3 phasesDegrees
MCLTEMPTraction motor coil temperatureDegrees
G_PHTMPThe highest generator motor inverter temperature within the 3 phases
GCLTEMPGenerator motor coil temperatureDegrees
G_SPEEDGenerator motor speedRPM
TQ_DSDDesired Total torqueNm
MTQ_CMDDesired traction motor torqueNm
GTQ_OUTDesired generator motor torqueNm
CONTACTTraction battery contractor status TCM receivedOpen/Closed
ABS_STATABS system status TCM receivedActivated/Not Activated
G_SDN_AGenerator motor shutdown TCM receivedOn/Off
M_SDN_CGenerator motor shutdown TCM receivedOn/Off
M_SDN_ATraction motor shutdown TCM receivedOn/Off
M_SDN_CTraction motor shutdown TCM receivedOn/Off
HVINTLCKHigh voltage interlock circuit statusOn/Off
TCM_HAZHazard indicator commandedOn/Off
TCM_CAUPowertrain malfunction indicator (wrench) commandedOn/Off
PRNDL_TGear selector position TCM receivedSelector position
MECTMotor electronics coolant temperature TCM receivedDegrees

NON-EMISSION FREEZE FRAME DATA TABLE

Flash Electrically Erasable Programmable Read Only Memory (EEPROM)

WARNINGThis vehicle is equipped with high voltage cables, components, and wiring. The high voltage warning labels containing the high voltage symbol are located on each high voltage component. High voltage cables and wiring are orange in color. Certified rubber insulating gloves and a face shield must be worn when working with the high voltage cables, components, or wiring. The ignition key must be cycled to the OFF position for a minimum of 5 minutes, and the high voltage traction battery service disconnect plug placed in the servicing/shipping position before disconnecting the high voltage cables. Do not disconnect, disable, or touch the high voltage cables, components, or wiring during the module reprogramming procedure because high voltage is present. Failure to follow these instructions may result in personal injury or death.

Making Changes to the VID Block

A PCM which is programmed may require changes to be made to certain VID information to accommodate vehicle hardware. Refer to PCM/Module Reprogramming on the scan tool.

PCM Reprogramming

Note. After the PCM is successfully reprogrammed, clear any TCM DTCs that may have been stored during reprogramming.

At certain times, the entire EEPROM needs to be completely reprogrammed. This is due to changes made to the strategy or calibration after production or the need to reset the VID block because it has reached its limit. Refer to PCM/Module Reprogramming on the scan tool.

Transaxle Control Module (TCM) Reprogramming

WARNINGThis vehicle is equipped with high voltage cables, components, and wiring. The high voltage warning labels containing the high voltage symbol are located on each high voltage component. High voltage cables and wiring are orange in color. Certified rubber insulating gloves and a face shield must be worn when working with the high voltage cables, components, or wiring. The ignition key must be cycled to the OFF position for a minimum of 5 minutes, and the high voltage traction battery service disconnect plug placed in the servicing/shipping position before disconnecting the high voltage cables. Do not disconnect, disable, or touch the high voltage cables, components, or wiring during the module reprogramming procedure because high voltage is present. Failure to follow these instructions may result in personal injury or death.

Drive Cycles

WARNINGStrict 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 or death.
  1. 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.
  2. Fuel tank level should be between 1/2 and 3/4 full with 3/4 full being the most desirable.
  3. The evaporative monitor can only operate 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.
  4. When bypassing the EVAP engine soak timer, the PCM must remain powered (key in ON position) after the clearing the continuous DTCs and relearning emission diagnostic information. For best result, follow each of the following steps as accurately as possible: OBD Monitor Exercised Drive Cycle Procedure Purpose of Drive Cycle Procedure Drive Cycle Preparation 1. Install the scan tool. Turn the key ON with the engine OFF. Cycle key OFF, then ON. Select appropriate vehicle and engine qualifier. Clear the continuous diagnostic trouble codes (DTCs) and reset the emission monitors information in the powertrain control module (PCM). Bypass the engine soak timer. Resets OBD Monitor status. 2. Begin to monitor the following PIDs (if available): ECT, EVAPDC, FLI and TP MODE. Start the vehicle WITHOUT returning to key OFF. 3. Idle the vehicle for 15 seconds. Drive at 64 km/h (40 mph) until the ECT is at least 76°C (170°F). Prep for Monitor Entry 4. Is IAT within 4° to 37°C (40° to 100°F)? If not, complete the following steps, but note that step 13 is required to bypass the EVAP monitor and clear the P1000. Engine warm-up and provide IAT input to the PCM. HO2S 5. Cruise at 64 km/h (40 mph) for at least 5 minutes. Executes the HO2S monitor. EVAP 6. Cruise at 64 to 89 km/h (40 to 55 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%. Executes the EVAP monitor if the IAT is within 4° to 40°C (40° to 100°F). Catalyst 7. Drive in stop-and-go traffic conditions. Include 5 different constant cruise speeds, ranging from 32 to 112 km/h (20 to 70 mph) over a 10 minute period. Executes the catalyst monitor. EGR 8. From a stop, accelerate to 72 km/h (45 mph) at 1/2 to 3/4 throttle. Repeat 3 times. Executes the EGR monitor. CCM (Engine) 9. Bring the vehicle to a stop. Idle with the gear selector in DRIVE position for 2 minutes. Executes the idle air control portion of the CCM. Misfire & Fuel Monitors 10. Profile learning is carried out after the PCM commands engine shutdown, the fuel injectors are disabled and the generator motor spins the engine. After the profile is learned, the engine shuts down. The profile learning may require up to 4 seconds. The traction battery must be within its operating limits to carry out the profile learning. Allows learning for the misfire monitor. Readiness Check 11. 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 12. With the scan tool, check for pending codes. Conduct normal repair procedures for any pending code concern. Otherwise, repeat any incomplete monitor. If the EVAP monitor is not complete and IAT was out of the 4° to 37 °C (40° to 100°F) temperature range in step 4, or the altitude is over 2,438 m. (8,000 ft.), the EVAP bypass procedure must be followed. Go to Step 13. Determines if a pending code is preventing the clearing of DTC P1000. EVAP Monitor Bypass 13. Park the vehicle for a minimum of 8 hours. Repeat steps 2 through 12. Do not repeat step 1. Allow the bypass counter to increment to 2.

Recreating the Fault

Recreating the fault is the first step in isolating the cause of the intermittent symptom. A thorough investigation should start with the customer information worksheet located in the back of the book. If freeze frame data is available, it may help in recreating the conditions at the time of a malfunction indicator lamp (MIL) diagnostic trouble code (DTC). Listed below are some of the conditions for recreating the fault

Engine Type ConditionsNon-Engine Type Conditions
Engine temperatureAmbient temperature
Engine RPMMoisture conditions
Engine loadRoad conditions (smooth-bumpy)
Engine idle/accel/decel

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 fault is occurring to prevent improper diagnosis. Data should be accumulated during different operating conditions and based on the customer description of the intermittent fault. Compare this data with the known good data values located in the TYPICAL DIAGNOSTIC REFERENCE VALUES . This requires recording data in 4 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 fault area. Typically, it requires the comparison of the actual values from the vehicle to the typical values from the TYPICAL DIAGNOSTIC REFERENCE VALUES .

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 the throttle position (TP) or mass air flow (MAF), as well as RPM that changes abruptly when the vehicle is traveling at a constant speed are clues to a possible fault area.

Look for agreement in related signals. For example, if the APP1, APP2 and APP3 are changed during acceleration, a corresponding change should occur in TP1, TP2, LOAD, RPM and MAF V PIDs.

Make sure the signals act in proper sequence. An increase in RPM after the TP1 and TP2 are increased is expected. However, if RPM increases without a TP1 and TP2 change, then a fault may exist.

Scroll through the PID data while analyzing the information. Look for sudden drops or spikes in the values.