Engine Controls - Diagnostic Methods (Except Diesel & Hybrid) (Section 2): Other Ford Explorer V

Vehicle Check And Preparation

Before using the scan tool to carry out any test, refer to the important Safety Notice and the necessary visual checks listed below.

Visual Checks

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 electronic engine control (EEC) system wiring harness for proper connections, bent or broken pins, corrosion, loose wires, and proper routing.
4. Check the powertrain control module (PCM), sensors, and actuators for physical damage.
5. Check the engine coolant for proper level and mixture.
6. Check the transmission fluid level and quality.
7. Make all necessary repairs before continuing with the quick test. For additional information, refer to «QUICK TEST DESCRIPTION»(ref-477698-S05525204002012060700000) .

Vehicle Preparation

1. 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.
2. Turn off all electrical loads such as radios, lamps, A/C, blower, and fans.
3. 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).

Ford PID List

Note. This is not a complete list of Ford PIDs available. This is a list of Ford PIDs in this service information.

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.

FREEZE FRAME DATA REFERENCE CHART

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 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.

MISFIRE FREEZE FRAME PIDS REFERENCE CHART

Manufacturer Specific Freeze Frame

The manufacturer specification 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.

MANUFACTURER SPECIFIC FREEZE FRAME PIDS REFERENCE CHART

Neutral Profile Correction - Fiesta

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. Neutral profile should be relearned any time the PCM, CKP sensor or the crankshaft pulse wheel is replaced or major engine repairs have been completed.

Misfire detection is active before profile learning has been completed using default thresholds. When neutral profile has been learned the vehicle specific thresholds are then used.

Neutral profile correction is learned on the road by decelerating with deceleration fuel shut off (DFSO) active. Profile correction is continuous throughout the lifetime of the vehicle, whenever the learning conditions are met adaptation takes place. The neutral profile correction can only be completed using the OBD Drive Cycle. For additional information, refer to the ON BOARD DIAGNOSTIC (OBD) DRIVE CYCLE .

Neutral Profile Correction - All Others

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

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. The fuel tank level should be between 1/2 and 3/4 full with 3/4 full being the most desirable.

For best results, follow each of the following steps as accurately as possible

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. The 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 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.
4. 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

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

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 from REFERENCE 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, APP2, or APP3 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

1. 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.
2. 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).
3. Vacuum leaks result in large rich corrections (positive LONGFT1 and LONGFT2 values) at idle, but little or no correction at higher RPM and loads.
4. 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/fuel ratio) if the powertrain control module (PCM) is not able to compensate enough to correct for the condition. One possibility is the mass of air entering the engine is actually greater than what the MAF sensor is indicating to the PCM. For example, with a contaminated MAF sensor, the engine runs lean at higher RPM because the PCM delivers fuel for less air than is actually entering the engine. Example

1. 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/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 or a MAF sensor concern. In this situation, the volume of air entering the engine is actually greater than what the MAF sensor is indicating to the PCM. 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, a stuck, frozen or aftermarket positive crankcase ventilation (PCV) valve, and unseated engine oil dipstick.

Insufficient Fueling

With this condition, the engine runs lean of stoichiometry (14.7:1 air/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

1. low fuel pressure (fuel pump, fuel filter, fuel leaks, restricted fuel supply lines)
2. fuel injector concerns

Exhaust System Leaks

In this type of condition, the engine runs rich of stoichiometry (14.7:1 air/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

1. exhaust system leaks upstream or near the HO2S
2. cracked/leaking HO2S boss

With this condition, the engine runs rich or lean of stoichiometry (14.7:1 air/fuel ratio) if the PCM is not able to compensate enough to correct for the condition. One possibility, the MAF sensor measurement is inaccurate due to a corroded connector, contamination or dirt on the MAF sensor screen or element. 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).

Fuel System

With this condition, the engine runs rich of stoichiometry (14.7:1 air/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

1. 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.
2. fuel injector leaks (injector delivers extra fuel).
3. evaporative emission (EVAP) purge valve leak (if the canister is full of vapors, introduces extra fuel).
4. 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 driver module (FPDM), causing high fuel pressure (system rich at all airflows).

Intake Air System

A restriction within any of the following components may be significant enough to affect the ability of the PCM adaptive fuel control.

1. air inlet tube
2. air cleaner element
3. air cleaner assembly
4. resonators
5. clean air tube

Base Engine

Engine oil contaminated with fuel can contribute to a rich running engine.