Overview
The Diagnostic Methods Section provides information on routine diagnostic tasks.
When following powertrain diagnostics on vehicles with on board diagnostics (OBD), the system may be checked by an off-board tester referred to as a scan tool. This part contains information for carrying out diagnostics with a scan tool. A scan tool has certain generic capabilities that are standard across the automotive industry in the United States and Canada. All functions are selected from a menu. Refer to the instruction article provided by the tool manufacturer.
International Standards Organization (ISO) 14229 Diagnostic Trouble Code (DTC) Descriptions
The ISO 14229 DTC is a set of common requirements for diagnostic systems. The scan tool displays a failure type and a status type with the DTC. The types display additional information on the scan tool for the condition that set the DTC. For a list of failure type descriptions, refer to POWERTRAIN CONTROL SOFTWARE , International Standards Organization (ISO) 14229 Diagnostic Trouble Code (DTC) Descriptions.
Description
All on board diagnostics (OBD) scan tools support the clearing of continuous DTCs and resetting of emission monitors information in the PCM.
The clearing of the continuous DTCs allows the scan tool to command the PCM to clear/reset all emission-related diagnostic information. While carrying out this operation DTC P1000 is stored in the PCM until all the OBD system monitors or components have been tested to satisfy a drive cycle without any other concerns occurring. For more information about a drive cycle, refer to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .
The following events occur when the continuous DTCs and the emission monitors information is cleared from the PCM
- the number of DTCs is reset
- the DTCs are cleared
- the freeze frame data is cleared
- the diagnostic monitoring test results are reset
- the status of the OBD system monitors is reset
- DTC P1000 is set
Resetting the KAM returns the powertrain control module (PCM) memory to its default setting. Adaptive learning contents such as adaptive airflow, idle speed, refueling event, and fuel trim are included. Clear the continuous diagnostic trouble codes (DTCs) in the PCM and reset the emission monitors information, is part of a KAM reset. Refer to CLEAR THE CONTINUOUS DIAGNOSTIC TROUBLE CODES (DTCS) AND RESET THE EMISSION MONITORS INFORMATION IN THE POWERTRAIN CONTROL MODULE (PCM) . Both can be useful in post-repair testing.
After the KAM has been reset, the vehicle may exhibit certain driveability concerns. It is necessary to allow the engine to idle at normal operating temperature with the air conditioning (A/C) OFF for 2 minutes. Then drive the vehicle to allow the PCM to learn the values for optimum driveability and performance.
This function may not be supported by all scan tools. Refer to the scan tool manufacturer's instruction article.
If an error message is received or the scan tool does not support this function, disconnecting the battery ground cable for a minimum of 5 minutes may be used as an alternative procedure.
All on board diagnostic (OBD) scan tools display the on-board system readiness (OSR) test. The OSR displays the supported monitors on the vehicle and the status of all monitors (complete or not complete) at that time. Fuel, misfire, and comprehensive component monitors (CCMs) run continuously and always display YES status. Clearing the continuous diagnostic trouble codes (DTCs) and resetting the emission monitors information in the powertrain control module (PCM), or resetting the keep alive memory (KAM) causes the non-continuous monitors to change to a NO status.
A detailed description of completing the OBD monitors is found. Refer to ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .
| WARNING | Safety must be observed when using OSC. Failure to follow these instructions may result in personal injury. |
The OSC aids in diagnosing output actuators associated with the powertrain control module (PCM) for the engine. This mode allows the technician to command the individual actuator state. For example: the output can be enabled or disabled, the duty cycle or the angle of the output can be increased or decreased. The OSC is used to help test the electrical, hydraulic or mechanical components of the vehicle. This function is supported by the vehicle strategy but may not be present on all vehicles or available on all scan tools.
Retrieve the continuous codes and carry out a key on, engine off (KOEO) and key on, engine running (KOER) on-demand self-test before using any OSC. Any diagnostic trouble codes (DTCs) related to the transmission range (TR) sensor, output shaft sensor (OSS) or the vehicle speed sensor (VSS) must be fixed or the PCM does not allow the OSC to operate.
The OSC has 2 options for operation, the Bench Mode and the Drive Mode. The Bench Mode is functional only when the vehicle gear selector is in the PARK or NEUTRAL position. The Bench Mode may be used when the engine is on (running) or off (not running).
Each OSC function has a unique set of vehicle operating requirements that the technician is required to meet before operating the OSC. If the vehicle requirements are not met while commanding the OSC value, an error message appears. When the error message is received, OSC is canceled.
To confirm that the scan tool sent the OSC value and the PCM has accepted the OSC substitution, a corresponding parameter identification (PID) for each OSC parameter must be monitored.
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.
| WARNING | Safety must be observed when using OTM. When all outputs are on, the electric fuel pump is briefly energized. Make sure the fuel system is intact and is not being repaired at this time. When low speed or high speed fan control(s) are turned on, make sure the fan blades are clear of any obstruction. Failure to follow these instructions may result in personal injury. |
The OTM aids in diagnosing output actuators associated with the powertrain control module (PCM). This mode allows the technician to energize and de-energize most of the system output actuators on command. When entering OTM, the outputs can be turned off and on without activating the fan control. The low and high speed fan controls may be turned on separately without energizing the other outputs. This function is supported by each vehicle strategy and may not be available on all scan tools.
As a safety precaution, OTM defaults to the off state after 10 minutes, and the fuel pump off state after approximately 7-10 seconds. OTM also turns off after the vehicle is started or after cycling the key off then on.
The PID mode allows access to powertrain control module (PCM) information. This includes analog and digital signal inputs and outputs along with calculated values and the system status. There are 2 types of PID lists available and both are used throughout this article. The first is the generic (J1979) OBD PID list. This is a standard set of PIDs that all scan tools must be able to access. The second is a Ford-specific (J2190) list which can be accessed by an appropriate scan tool. When accessing any of these PIDs, the values are continuously updated. The generic or Ford PID list provides definitions and values in appropriate units. For more information, refer to the Society of Automotive Engineers (SAE) document J2205.
Freeze frame data allows access to emission-related values from specific generic parameter identification (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 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 |
|---|---|---|
| AAT | Ambient Air Temperature | Degrees |
| AIR | Secondary Air Status | |
| APP_D | Accelerator Pedal Position D | % |
| APP_E | Accelerator Pedal Position E | % |
| APP_F | Accelerator Pedal Position F | % |
| 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 |
| 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 | % |
| EVAPVP | Evaporative System Vapor Pressure | Pa |
| 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 Air Flow Rate | G/s |
| MAP | Manifold Absolute Pressure | KPa |
| 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 Warm-ups Since Code Cleared | Units |
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 MIL code. They 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, and 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.)
Note. 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 RPM | Engine RPM at the time of misfire | RPM |
| MFF LOAD | Engine load at the time of misfire | % |
| MFF VSS | Vehicle speed at the time of misfire | Km/h-mph |
| MFF IAT | Intake air temperature at the time of misfire | Degrees |
| MFF SOAK | Engine-off soak time at the time of misfire | Time |
| MFF RNTM | Engine running time at the time of misfire | Time |
| MFF EGR | EGR DPFE sensor at the time of misfire | Volts |
| MFF TP | Throttle Position at 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 PNP | 1= in DRIVE during the time of misfire | Mode |
| MP LRN | 1= Misfire wheel profile learned in KAM | Yes/No |
MISFIRE FREEZE-FRAME PIDS
The EEPROM is contained in an integrated circuit internal to the powertrain control module (PCM). The EEPROM contains the vehicle strategy including calibration information specific to the vehicle, and is capable of being programmed or flashed repeatedly.
As part of the calibration there is an area referred to as the vehicle identification (VID) block. The VID block is programmed when installing a new PCM as described under Programming the VID Block for a Replacement PCM. Failure to carry out this procedure may generate DTCs P1635 or P1639. The VID block in an existing PCM can also be tailored to accommodate various hardware or parameter changes made to the vehicle since production. Failure to carry out this procedure properly may generate DTC P1635, Tire/Axle Ratio out of Acceptable Range. An incorrect tire/axle ratio is one of the main causes for DTC P1639. This is described under Making Changes to the VID Block and also under Making Changes to the PCM Calibration. The VID block contains many items used by the strategy for a variety of functions. Some of these items include the vehicle identification number (VIN), octane adjust, fuel octane, fuel type, vehicle speed limit, tire size, axle ratio, the presence of speed control, and 4-wheel drive electronic shift-on-the-fly (ESOF) versus manual shift-on-the-fly (MSOF). Only items applicable to the vehicle hardware and supported by the VID block is displayed on the scan tool.
When changing items in the VID block, the strategy places range limits on certain items such as tire and axle ratio. The number of times the VID block may be reconfigured is limited. When this limit is reached, the scan tool displays a message indicating the need to flash the PCM again to reset the VID block.
Programming can be carried out by a local Ford dealer or any non-Ford facility. Refer to the scan tool manufacturer's instruction article for details.
Description of On Board Diagnostic (OBD) Drive Cycle
The following procedure is designed to execute and complete the OBD monitors and to clear the Ford P1000, I/M readiness code. To complete a specific monitor for repair verification, follow steps 1 through 4, then continue with the step described by the appropriate monitor found under the OBD Monitor Exercised column. For the EVAP/secondary AIR monitor to run, the ambient air temperature must be between 4.4 to 37.8°C (40 to 100°F), and the altitude below 2,438 meters (8,000 feet). If the P1000 code must be cleared in these conditions, the powertrain control module (PCM) must detect them once (twice on some applications) before the EVAP monitor can be bypassed and diagnostic trouble code (DTC) P1000 is cleared. The EVAP bypassing procedure is described in the following drive cycle.
The OBD drive cycle is carried out using a scan tool. Refer to the manufacturer's instruction article for each described function.
A detailed description for clearing the DTCs is found. Refer to CLEAR THE CONTINUOUS DIAGNOSTIC TROUBLE CODES (DTCS) AND RESET THE EMISSION MONITORS INFORMATION IN THE POWERTRAIN CONTROL MODULE (PCM) .