Important Safety Notice
Appropriate repair methods and procedures are essential for the safe, reliable operation of all motor vehicles, as well as the personal safety of the individual doing the work. This article provides general directions for repairing vehicles with tested, effective techniques. Following them helps to establish reliability.
There are numerous variations in procedures, techniques, tools, and parts for repairing vehicles, as well as in the skill of the individual doing the work. This article cannot possibly anticipate all such variations and provide advice or cautions as to each. Accordingly, anyone who departs from the instructions provided in this article must first establish that they compromise neither their personal safety nor the vehicle integrity by their choice of methods, tools, or parts.
NOTE, NOTICE, CAUTION AND WARNING
As you read through this article, you may come across a NOTE, NOTICE, CAUTION or WARNING. Each one is used for a specific purpose. A NOTE calls attention to unique, additional or essential information related to the subject procedure. A NOTICE or CAUTION identifies a hazard that could damage the vehicle or property. A WARNING identifies a hazard that could result in personal injury or death to yourself or others. Some general WARNINGS that you should follow when you work on a vehicle are listed below.
- ALWAYS WEAR SAFETY GLASSES FOR EYE PROTECTION.
- KEEP SOLVENTS AWAY FROM IGNITION SOURCES. SOLVENTS MAY BE FLAMMABLE AND COULD IGNITE OR EXPLODE IF NOT HANDLED CORRECTLY.
- USE SAFETY STANDS WHENEVER A PROCEDURE REQUIRES YOU TO BE UNDER THE VEHICLE.
- MAKE SURE THAT THE IGNITION SWITCH IS ALWAYS IN THE OFF POSITION, UNLESS OTHERWISE REQUIRED BY THE PROCEDURE.
- SET THE PARKING BRAKE WHEN WORKING ON THE VEHICLE. IF YOU HAVE AN AUTOMATIC TRANSMISSION, SET IN PARK UNLESS INSTRUCTED OTHERWISE FOR A SPECIFIC OPERATION. IF YOU HAVE A MANUAL TRANSMISSION, IT SHOULD BE IN REVERSE (ENGINE OFF) OR NEUTRAL (ENGINE ON) UNLESS INSTRUCTED OTHERWISE FOR A SPECIFIC OPERATION. PLACE WOOD BLOCKS (4" X 4" OR LARGER) OR WHEEL CHOCKS AGAINST THE FRONT AND REAR SURFACES OF THE TIRES TO HELP PREVENT THE VEHICLE FROM MOVING.
- OPERATE THE ENGINE ONLY IN A WELL-VENTILATED AREA TO AVOID THE DANGER OF CARBON MONOXIDE POISONING.
- KEEP YOURSELF AND YOUR CLOTHING AWAY FROM MOVING PARTS WHEN THE ENGINE IS RUNNING, ESPECIALLY THE DRIVE BELTS.
- TO PREVENT SERIOUS BURNS, AVOID CONTACT WITH HOT METAL PARTS SUCH AS THE RADIATOR, EXHAUST MANIFOLD, TAIL PIPE, THREE-WAY CATALYTIC CONVERTER AND MUFFLER.
- DO NOT SMOKE WHILE WORKING ON A VEHICLE.
- TO AVOID INJURY, ALWAYS REMOVE RINGS, WATCHES, LOOSE HANGING JEWELRY AND LOOSE CLOTHING BEFORE BEGINNING TO WORK ON A VEHICLE.
- WHEN IT IS NECESSARY TO WORK UNDER THE HOOD, KEEP HANDS AND OTHER OBJECTS CLEAR OF THE COOLING FAN BLADES!
Preface
This article provides a step-by-step approach for diagnosing driveability, emission, powertrain and hybrid-electric control system symptoms. Before beginning diagnosis, it may be helpful to reference any Technical Service Bulletins (TSBs) or On-line Automotive Service Information System (OASIS) information when this is available. The TSB/OASIS information is available on the Professional Technician Society (PTS) or Motorcraft® website.
This article is used in conjunction with the Workshop article and Wiring Diagrams. The Workshop article is used to provide additional diagnostics when directed by this article. The Workshop article is also used for component removal and installation information. Refer to the Wiring Diagrams for vehicle-specific wiring information and component, connector and splice location.
The following is a description of the information contained in each part of this article.
Pinpoint Tests
This part contains all pinpoint tests. Never enter a pinpoint test unless directed there. When directed to a pinpoint test, always read the information included at the beginning of the pinpoint test.
Reference Values
This part contains the Typical Diagnostic Reference Values charts. The technician is directed to these charts from Pinpoint Test Z in the PINPOINT TESTS article.
What's New in this article
A/C evaporator temperature (ACET) and A/C control head driver inputs are monitored by the dual automatic temperature control (DATC) module and communicated to the PCM through the controller area network (CAN) for freeze control protection.
Acronyms and Definitions
Note. This acronyms and definitions listing contains technical terms applicable to Ford Motor Company products. It is not intended to be an all-inclusive dictionary of components and their functions. If a detailed description of a particular system or component is desired, refer to the applicable part within this PC/ED article or consult the Workshop article for the specific vehicle being repaired.
- 4V: Four valves per engine cylinder
- ABS: Anti-Lock Brake System
- A/C: Air Conditioning
- A/CC: Air Conditioning Clutch
- A/CCR: A/C Clutch Control Relay
- A/CLPCS: A/C Low Pressure Cycling Switch
- ACCS: Air Conditioning Cycling Switch
- ACET: Air Conditioning Evaporator Temperature
- ACP: Air Conditioning Head Pressure or A/C cycling switch input state
- ACPSW: Air Conditioning Pressure Switch
- ACRDV: Air Conditioning (A/C) Refrigerant Distribution Valve
- A/D: Analog-to-Digital. Analog-to-Digital signal conversion.
- Air/Fuel Ratio: Air-to-fuel mixture ratio. An air-to-fuel mixture that is 14.7:1 is also called stoichiometric.
- Ambient Air Temperature: Temperature of the air surrounding an object
- Analog (Electrical/Electronic): An electrical signal that can obtain any value within the voltage limits of the signal.
- APP: Accelerator Pedal Position
- ARB: Air Resource Board
- ASCII: American Standard Code Information Interchange
- ATDC: After Top Dead Center
- BARO: Barometric Pressure
- Base Timing: Spark advance in degrees before top dead center of the base engine without any control from the PCM.
- Battery Positive Voltage (B+): The positive (+) voltage from the battery or any circuit connected directly to the battery.
- BATTEMP: Battery Temperature
- BJB: Battery Junction Box
- BPA: Brake Pedal Applied. Typically located on the braking system master cylinder. Can be hydraulic or electric.
- BPO: Battery Power Off
- BPP: Brake Pedal Position
- BPS: Brake Pedal Switch/Speed Control Deactivation
- BTDC: Before Top Dead Center
- BVREF: Buffer Voltage Reference. A dedicated circuit that provides an approximately 5-volt signal used as a reference by certain sensors.
- CAFE: Corporate Average Fuel Economy. A set of federal requirements and regulations that govern fuel economy standards.
- CANVNT: Canister Vent
- CAN: Controller Area Network
- CCM: Comprehensive Component Monitor
- CD A through D: Coil Driver 1 through 4
- Centralized Testing Facility: State government operation. Provides inspection/maintenance (IM) and safety inspections.
- CGND: Case Ground. Provides a ground source for the PCM or ECU case.
- CHT: Cylinder Head Temperature. Units are displayed in degrees Fahrenheit or degrees Celsius.
- CHTV: Cylinder Head Temperature Voltage
- CKP: Crankshaft Position
- CL: Closed Loop. An operating condition or mode that enables operation based on sensor feedback.
- CMP: Camshaft Position. PCM input signal from the camshaft position sensor.
- CMS: Catalyst Monitor Sensor. The downstream heated oxygen sensor (HO2S).
- CMVSS: Canadian Motor Vehicle Safety Standards
- CO: Carbon Monoxide. A colorless, odorless and toxic gas that is a component of auto exhaust emissions.
- CO 2 : Carbon Dioxide. A colorless, odorless gas that is a normal by-product of the combustion of fuel.
- Cold Soak: Time given to a vehicle to sit at a low temperature, typically below 20°C (68°F), until the temperature of external and internal components stabilizes.
- CONT: Continuous Memory. The portion of keep alive memory (KAM) used to store DTCs generated during the continuous memory self-test.
- COP: Coil On Plug
- CSE GND: Case Ground
- CT: Closed Throttle. A mode when the PCM varies the pulse width of the fuel injectors to obtain the air/fuel mixture appropriate for closed throttle operation.
- CTO: Clean Tach Output
- DATC: Dual Automatic Temperature Control
- DC: 1. Direct Current. Electric current flowing in 1 direction. 2. Duty Cycle. The voltage measurement of ON time versus the full cycle period, expressed in percent.
- DCL: Data Communication Link. A communication path between various in-vehicle electronic modules. Accessed by scan tools through the data link connector (DLC).
- Digital: Controls process information by switching the current or voltage ON and OFF.
- DLC: Data Link Connector. J1962 connector providing access to vehicle diagnostic information.
- DMM: Digital Multimeter
- DOHC: Dual Overhead Cam. An engine configuration that uses 2 camshafts positioned above the valves.
- DTM: Diagnostic Test Mode. A level of capability in an on board diagnostics (OBD) system.
- DTC: Diagnostic Trouble Code. An alpha/numeric identifier for a concern identified by the OBD system.
- ECT: Engine Coolant Temperature. Displayed in degrees Fahrenheit or degrees Celsius.
- ECVT: Electronically Controlled Continuously Variable Transaxle
- EEC: Electronic Engine Control
- EEGR: Electric Exhaust Gas Recirculation
- EEPROM: Electrically Erasable Programmable Read-Only Memory. An electronic component in the PCM that allows the electronic storage of information.
- EGR: Exhaust Gas Recirculation. A process in which a small amount of exhaust gas is routed into the combustion chamber.
- EI: Integrated Electronic Ignition. An electronic ignition system that has the ignition control module (ICM) integrated into the PCM.
- EI-LDR: Electronic Ignition-Low Data Rate
- EMI: Electromagnetic Interference. Usually caused by ignition voltage spikes, solenoids, relay operation, or noisy generator contacts.
- EOT: Engine Oil Temperature
- EPA: Environmental Protection Agency
- ESM: EGR System Module
- ETC: Electronic Throttle Control
- ETCVREF: Voltage Reference
- EVAP: Evaporative Emissions. A system to prevent fuel vapor from escaping into the atmosphere.
- Evaporative Emissions Canister: An evaporative emission canister containing activated charcoal that absorbs and holds fuel vapors.
- EVO: Electronic Variable Orifice
- EVMV: Electric Vapor Management Valve. Also known as the EVAP canister purge valve.
- Exciter Ring: A toothed or notched iron or steel disk that is the moveable part of a speed sensor.
- FAN: Fan Speed
- FC: Fan Control
- FCS: Fuel Control Solenoid
- FCIL: Fuel Cap Indicator Lamp. Indicates the fuel filler cap is not correctly installed.
- FEAD: Front End Accessory Drive
- FEPS: Flash EEPROM Programming Signal. 18-volt DC signal sent by the scan tool to initiate PCM reprogramming.
- FLI: Fuel Level Input. Used by the EVAP monitor to calculate fuel tank vapor volume. Displayed as a percentage.
- FMEM: Failure Mode Effects Management. Operating strategy that maintains limited vehicle function in the event of a PCM or EEC component failure.
- FP: Fuel Pump
- FPDM: Fuel Pump Driver Module. A module that controls the electric fuel pump.
- FRPT: Fuel Rail Pressure Temperature Sensor
- FTIV: Fuel Tank Isolation Valve
- FTP: Fuel Tank Pressure
- FWD: Front-Wheel Drive
- GCU: Generator Control Unit
- GND: Ground
- GPM: Grams per Mile. Also known as Gallons per Minute.
- GSDN: Generator Motor Shutdown
- GVW: Gross Vehicle Weight
- Hall Effect: A process where current is passed through a small portion of semiconductor material and a magnetic field to produce a small voltage in the semiconductor.
- HC: Hydrocarbon
- HO2S: Heated Oxygen Sensor
- HVIL: High Voltage Interlock Circuit
- HVIN: High Voltage Interlock Negative Circuit
- HVIP: High Voltage Interlock Positive Circuit
- HVN: High Voltage Negative Circuit
- HVP: High Voltage Positive Circuit
- Hz: Hertz
- IAT: Intake Air Temperature
- IFS: Inertia Fuel Shut-Off
- IGN GND: Ignition Ground
- IMAP: Inferred Manifold Absolute Pressure (MAP)
- IPC: Independent Plausibility Checker
- ISDN1, ISDN2: Immediate Shutdown Circuits 1 and 2
- ISP-R: Ignition Switch Position RUN Circuit
- ISP-R/S: Ignition Switch Position START Circuit
- ISO: International Standards Organization
- ITCC: Intelligent Torque-Controlled Coupling
- KAM: Keep Alive Memory
- KAPWR: Keep Alive Power
- KEYPWR: Key Power
- KOEO Self-Test: Key On Engine Off self-test
- KOER Self-Test: Key On Engine Running self-test
- Km/h: Kilometers per Hour
- kPa: Kilopascals. Unit of pressure. 3.386 kPa equals 1 inch of mercury (Hg).
- LDR: Low Data Rate
- LOAD: Calculated Engine Load
- LONGFT1: Long-Term Fuel Trim Bank 1
- MAF: Mass Air Flow
- MAF RTN: Mass Air Flow Return. A return circuit for the MAF sensor.
- MAP: Manifold Absolute Pressure. The internal pressure of the intake manifold.
- MCLTEMP: Traction Motor Coil Temperature
- MCU: Motor Control Unit
- MECP: Motor Electronics Coolant Pump
- MECT: Motor Electronics Coolant Temperature
- MIL: Malfunction Indicator Lamp
- MSDN: Motor Shutdown
- NO X : Oxides of Nitrogen
- O2S: Oxygen Sensor
- OASIS: On-line Automotive Service Information System
- OBD: On Board Diagnostics
- OC: Oxidation Catalytic converter
- OHC: Overhead Cam
- OSC: Output State Control
- OTM: Output Test Mode
- PCM: Powertrain Control Module
- PCV: Positive Crankcase Ventilation
- PID: Parameter Identification
- PIP: Profile Ignition Pickup
- PPM: Parts per Million
- PROM: Programmable Read-Only Memory
- PSC Module: Power Steering Control Module
- PSR: Power Sustain Relay
- PWM: Pulse Width Modulation
- PWR GND: Power Ground
- PZEV: Partial Zero Emission Vehicle
- RAM: Random Access Memory
- RFI: Radio Frequency Interference
- ROM: Read-Only Memory
- RPM: Revolutions per Minute
- RTN: Return
- RWD: Rear-Wheel Drive
- SAE: Society of Automotive Engineers
- SFI: Sequential Multiport Fuel Injection
- SHRTFT1: Short-Term Fuel Trim Bank 1
- SIG RTN: Signal Return
- Stoichiometry: An air/fuel mixture that is neither too rich nor too lean. Stoichiometric ratio is 14.7 parts of air for every 1 part of fuel.
- TACM: Throttle Actuator Control Motor
- TB: Throttle Body
- TBCM: Traction Battery Control Module
- TCM: Transaxle Control Module
- TDC: Top Dead Center
- TFT: Transmission Fluid Temperature
- TGAC: Torque of Generator AC signal
- TMAC: Torque of Motor AC signal
- TP: Throttle Position
- TR Sensor: Transmission Range Sensor
- VBPWR: Vehicle Buffered Power
- VECI: Vehicle Emission Control Information
- VIN: Vehicle Identification Number
- VMV: Vapor Management Valve
- VPWR: Vehicle Power
- VREF: Reference Voltage
- VSC: Vehicle System Controller
- VSS: Vehicle Speed Sensor
- WAC: Wide Open Throttle A/C Cut-Off
- WOT: Wide Open Throttle