Engine Controls - Description and Operation - (Hybrid): Other Ford Escape I рестайлинг

VECI Decal

Each vehicle has a VECI decal containing emission control information that applies specifically to the vehicle and engine. The specifications on the decal are critical to repairing emissions systems.

Scheme 133

Scheme 134

Scheme 135

Engine/Evaporative Emission System Information

Manufacturers must use a standardized system for identifying their individual engine families. The engine family group and the evaporative family name consists of 12 characters each.

Both the engine family group and the evaporative family name are listed in the box on the emission decal as indicated in the area marked as engine evaporative family information. The first line contains the engine size and the 12-character engine family group. The second line contains the 12-character evaporative family name information. Both the engine family group and the evaporative family name are specific to the vehicle. Please refer to the Engine Family Group and the Evaporative Family Name work sheet for decoding information. (Scheme 134)and/or (Scheme 135)

Scheme 136

VECI Acronym Definitions

ALVW: Adjusted Loaded Vehicle Weight, (curb weight plus GVWR) divided by 2.

BBL: Barrel

CALIFORNIA ARB: California Air Resource Board

CARB: California Air Resource Board

CARB LEV: Low Emission Vehicle

CARB TLEV: Transitional Low Emission Vehicle

CARB ULEV: Ultra Low Emission Vehicle

CARB ZEV: Zero Emission Vehicle

EPA: Environmental Protection Agency

EVAP: Evaporative Emissions

GVW: Gross Vehicle Weight

GVWR: Gross Vehicle Weight Rating, curb weight plus payload.

LDV: Light Duty Vehicle, generally passenger cars and light trucks under 6000 pounds GVWR.

LVW: Loaded Vehicle Weight, curb weight plus 300 pounds.

MY: Model Year

OBD: On Board Diagnostic

ORVR: On-Board Refueling Vapor Recovery

SULEV: Super Ultra Low Emission Vehicle

Tier 0: California and Federal regulations effective prior to Tier 1 phase in dates.

Tier 1: California regulations beginning in 1993 model year and Federal regulations beginning in 1994 model year.

LEV: Low Emission Vehicle

ZEV: Zero Emission Vehicle

PZEV: Partial Zero Emission Vehicle

ULEV: Ultra Low Emission Vehicle

ILEV: Inherently Low Emission Vehicle

Catalyst Monitor Execution

Catalyst monitor execution is once per drive cycle. Typical monitor duration is 700 seconds. In order for the catalyst monitor to run, the HO2S monitor must be complete and EVAP system functional with no stored DTCs. If the catalyst monitor does not complete during a particular drive cycle, the already accumulated switch/signal data is retained in the KAM and is used during the next drive cycle to allow the catalyst monitor a better opportunity to complete.

Scheme 137

Comprehensive Component Monitor (CCM)

The CCM monitors for malfunctions in any powertrain electronic component or circuit that provides input or output signals to the powertrain control module (PCM) that can affect emissions and is not monitored by another OBD monitor. Inputs and outputs are, at a minimum, monitored for circuit continuity or proper range of values. Where feasible, inputs are checked for rationality, outputs are also checked for proper functionality.

The CCM covers many components and circuits and tests them in various ways depending on the hardware, function, and type of signal. For example, analog inputs such as the cylinder head temperature (CHT) sensor or the intake air temperature (IAT) sensor are typically checked for opens, shorts, and out-of-range values. This type of monitoring is carried out continuously. Some digital inputs like crankshaft position or camshaft position rely on rationality checks to see if the input value makes sense at the current engine operating conditions. These types of tests may require monitoring several components and can only be carried out under appropriate test conditions.

Outputs such as the vapor management valve (VMV) are checked for opens and shorts by monitoring a feedback circuit or smart driver associated with the output. Other outputs, such as relays, require additional feedback circuits to monitor the secondary side of the relay. Some outputs are also monitored for proper function by observing the reaction of the control system to a given change in the output command. Some tests can only be carried out under appropriate test conditions.

The following is an example of some of the input and output components monitored by the CCM. The components monitor may belong to the engine, ignition, air conditioning, or any other PCM supported subsystem.

1. Inputs: mass airflow (MAF) sensor, intake air temperature (IAT) sensor, cylinder head temperature (CHT) sensor, crankshaft position (CKP) sensor, camshaft position (CMP) sensor, air conditioning pressure sensor (ACPS), fuel rail pressure (FRP) sensor.
2. Outputs: fuel pump driver module (FPDM), A/C cutout (A/CCR), intake manifold runner control (IMRC), vapor management valve (VMV), canister vent (CV) solenoid.
3. The CCM is enabled after the engine starts and is running. A diagnostic trouble code (DTC) is stored in keep alive memory (KAM) and the malfunction indicator lamp (MIL) is illuminated after 2 driving cycles when a malfunction is detected. Many of the CCM tests are also carried out during the on demand self-test.

Scheme 138

Evaporative Emission (EVAP) Leak Check Monitor

The evaporative emission (EVAP) leak check monitor is an onboard strategy designed to detect a leak from a hole (opening) equal to or greater than 0.508 mm (0.020 in) in the enhanced EVAP system. The proper function of the individual components of the enhanced EVAP system as well as its ability to flow fuel vapor to the engine is also examined. The EVAP leak check monitor relies on the individual components of the enhanced EVAP system to apply vacuum to the fuel tank and then seal the entire enhanced EVAP system from the atmosphere. The fuel tank pressure is then monitored to determine the total vacuum lost (bleed-up) for a calibrated period of time. Inputs from the cylinder head temperature (CHT) sensor, intake air temperature (IAT) sensor, mass airflow (MAF) sensor, vehicle speed, fuel level input (FLI) and fuel tank pressure (FTP) sensor are required to enable the EVAP leak check monitor.

Note. During the EVAP leak check monitor repair verification drive cycle, clearing the diagnostic trouble codes (DTCs) bypasses the minimum soak time required to complete the monitor. The EVAP leak check monitor does not run if the key is turned off after clearing the DTCs. The EVAP leak check monitor does not run if a MAF sensor failure is indicated. The EVAP leak check monitor does not initiate until the heated oxygen sensor (HO2S) monitor has completed.

The EVAP leak check monitor is executed in 2 tests: the cruise test and the idle test. The cruise test executes when vehicle speed is above 64 km/h (40 mph). During this test the DTC P0455 is stored if a gross leak is detected, and the DTC P0422 is stored if a small leak is detected. When a very small leak is detected during this test the DTC will not be stored, however, the idle test is required to execute. The idle test starts only after a 6-hour key off soak and requires about 10 minutes to complete. The engine remains running, and the DTC P0446 is stored if the leak is present during this test. The engine returns to a normal operating mode after 10 minutes, regardless of the test result.

The EVAP leak check monitor is executed by the individual components of the enhanced EVAP system as follows

1. The vapor management valve (VMV) is used to control the flow of vacuum from the engine and create a target vacuum on the fuel tank.
2. The canister vent (CV) solenoid is used to seal the EVAP system from the atmosphere. It is closed by the PCM (100% duty cycle) which then allows the VMV to obtain the target vacuum on the fuel tank.
3. The FTP sensor is used by the EVAP leak check monitor to determine if the target vacuum on the fuel tank is being reached to carry out the leak check. Once the target vacuum on the fuel tank is achieved, the change in fuel tank vacuum for a calibrated period of time determines if a leak exists.
4. The fuel tank isolation valve (FTIV) isolates the fuel tank from the rest of the EVAP system. The FTIV allows the flow of vapors from the fuel tank to the VMV and the EVAP canister. Whenever it is desired to isolate the fuel tank from the rest of the EVAP system, the PCM provides a variable duty cycle signal (between 0% and 100%) to the solenoid which controls the FTIV operation.
5. If the initial target vacuum cannot be reached, DTC P0455 (gross leak detected) is set. The EVAP leak check monitor aborts and does not continue with the leak check portion of the test. If the initial target vacuum cannot be reached after a refueling event and the purge vapor flow is excessive, DTC P0457 (fuel cap off) is set. If the initial target vacuum is exceeded, a system flow fault exists and DTC P1450 (unable to bleed-up fuel tank vacuum) is set. The EVAP leak check monitor aborts and does not continue with the leak check portion of the test. If the target vacuum is obtained on the fuel tank, the change in the fuel tank vacuum (bleed-up) is calculated for a calibrated period of time. The calculated change in fuel tank vacuum is compared to a calibrated threshold for a leak from a hole (opening) of 0.508 mm (0.020 inch) in the enhanced EVAP system. If the calculated bleed-up is less than the calibrated threshold, the enhanced EVAP system passes. If the calibrated bleed-up exceeds the calibrated threshold, the test aborts reruns the test up to 3 times. If the bleed-up threshold is still being exceeded after 3 tests, a vapor generation check must be carried out before DTC P0442 (small leak detected) is set. This is accomplished by returning the enhanced EVAP system to atmospheric pressure by closing the VMV and opening the CV solenoid. Once the FTP sensor determines the fuel tank is at atmospheric pressure, the CV solenoid closes and seals the enhanced EVAP system. The fuel tank pressure build-up for a calibrated period of time is compared to a calibrated threshold for pressure build-up due to vapor generation. If the fuel tank pressure build-up exceeds the threshold, the leak test results are invalid due to vapor generation. The EVAP leak check monitor attempts to retest again. If the fuel tank pressure build-up does not exceed the threshold, the leak test results are valid and DTC P0442 is set. The calculated change in fuel vacuum over the extended time is compared to a calibrated threshold for a leak from a 0.508 mm (0.020 inch) hole (opening). If the calculated bleed-up exceeds the calibrated threshold, vapor generation is run. If vapor generation passes (no vapor generation), an internal flag is set in the PCM to run a 0.508 mm (0.020 inch) test at idle (vehicle stopped). On the next start following a long engine off period, the enhanced EVAP system is sealed and evacuated for the first 10 minutes of operation. If the appropriate conditions are met, a 0.508 mm (0.020 inch) leak check is conducted at idle. If the test at idle fails, a DTC P0456 is set. There is no vapor generation test with the idle test. NOTE: If the vapor generation is high on some vehicle enhanced EVAP systems, where the monitor does not pass, the result is treated as a no test. Thereby, the test is complete for the day.
6. The MIL is activated for DTCs P0442, P0455, P0456, P0457, P1450, (or P0446) after 2 occurrences of the same fault. The MIL can also be activated for any enhanced EVAP system component DTCs in the same manner. The enhanced EVAP system component DTCs P0443, P0452, and P0453 are tested as part of the CCM.

Scheme 139

Electric Exhaust Gas Recirculation (EEGR) System Monitor

The EEGR system monitor is an onboard strategy designed to test the integrity and flow characteristics of the exhaust gas recirculation (EGR) system. The monitor is activated during EGR system operation and after certain base engine conditions are satisfied. Input from the cylinder head temperature (CHT), intake air temperature (IAT), throttle position (TP), mass air flow (MAF), and manifold absolute pressure (MAP) sensors is required to activate the EGR system monitor. Once activated, the EGR system monitor carries out each of the tests described below during the engine modes and conditions indicated. Some of the EGR system monitor tests are also carried out during the on demand self-test.

The EEGR monitor consists of an electrical and functional test that checks the stepper motor and the EGR system for proper flow. The powertrain control module (PCM) controls the EGR valve by commanding from 0 to 52 discreet increments or steps to get the valve from fully closed to fully open. The stepper motor electrical test is a continuous check of the 4 electric stepper motor coils and circuits to the PCM. A malfunction is indicated if an open circuit, short to power, or short to ground has occurred in one or more of the stepper motor coils/circuits for a calibrated period of time. If a malfunction has been detected, the EGR system is disabled, setting the KOER, and continuous diagnostic trouble code (DTC) P0403. Additional monitoring is suspended for the remainder of the driving cycle, or until the next engine startup.

After the engine has warmed up and normal EGR rates are being commanded by the PCM, the EGR flow check is carried out. The flow test is carried out once per drive cycle when a minimum amount of EGR is requested and the remaining entry conditions required to initiate the test are satisfied. If a malfunction is detected, the EGR system and the EGR system monitor are disabled until the next engine startup.

The EGR flow test is done by observing the behavior of 2 different values of MAP - the analog MAP sensor reading, and inferred MAP (MAP calculated from the mass air flow sensor, throttle position, and RPM). During normal, steady-state operating conditions, the EGR is intrusively commanded ON to a specified percentage. Then, the EGR is commanded OFF. If the EGR system is working properly, there is a significant difference in both the observed and the calculated values of MAP between the EGR ON and the EGR OFF states.

When the flow test entry conditions have been satisfied, the EGR is commanded to flow at a calibrated test rate (about 10%). At this time, the value of MAP is recorded (EGR ON MAP). The value of inferred MAP EGR ON IMAP is also recorded. Next the EGR is commanded off (0%). Again, the value of MAP is recorded (EGR OFF MAP). The value of EGR OFF IMAP is also recorded. Typically, 7 such ON/OFF samples are taken. After all the samples have been taken, the average EGR ON MAP, EGR ON IMAP, EGR OFF MAP and EGR OFF IMAP values are stored.

Next, the differences between the EGR ON and EGR OFF values are calculated

1. MAP delta equals EGR ON MAP - EGR OFF MAP (analog MAP).
2. IMAP delta equals EGR ON IMAP - EGR OFF IMAP (inferred MAP).

If the sum of MAP delta and IMAP delta exceeds a maximum threshold or falls below a minimum threshold, a DTC P0400 (high or low flow malfunction) is registered.

As an additional check, if the EGR ON MAP exceeds a maximum threshold (BARO, a calibrated value), a DTC P0400 low flow malfunction is registered.

Note. BARO is inferred at engine startup using the key on engine off (KOEO) MAP sensor reading. It is updated during high, part-throttle or high RPM engine operation.

If the inferred ambient temperature is less than -7°C (20°F), greater than 54°C (130°F), or the altitude is greater than 8,000 feet (BARO less than 22.5 in Hg), the EGR flow test cannot be reliably done. In these conditions, the EGR flow test is suspended and a timer starts to accumulate the time in these conditions. If the vehicle leaves these extreme conditions, the timer starts to decrement, and if conditions permit, attempts to complete the EGR flow monitor. If the timer reaches 500 seconds, the EGR flow test is disabled for the remainder of the current driving cycle and the EGR monitor I/M readiness bit is set to a ready condition.

A DTC P1408, like P0400, indicates an EGR flow failure (outside the minimum or maximum limits) but is only set during the key on engine running (KOER) self test. The DTCs P0400 and P0403 are MIL codes, and the DTC P1408 is a non-MIL code.

Scheme 140

Fuel System Monitor

The fuel system monitor is an onboard strategy designed to monitor the fuel trim system. The fuel control system uses fuel trim tables stored in the powertrain control module (PCM) keep alive memory (KAM) to compensate for variability in fuel system components due to normal wear and aging. The fuel trim tables are based on engine RPM and engine load. During closed-loop fuel control, the fuel trim strategy learns the corrections needed to correct a biased rich or lean fuel system. The correction is stored in the fuel trim tables. The fuel trim has 2 means of adapting: long term fuel trim and a short term fuel trim. Both are described in greater detail in FUEL TRIM . Long term fuel trim relies on the fuel trim tables and short term fuel trim refers to the desired air/fuel ratio parameter called LAMBSE. LAMBSE is calculated by the PCM from the heated oxygen sensor (HO2S) inputs and helps maintain a 14.7:1 air/fuel ratio during closed-loop operation. Short term fuel trim and long term fuel trim work together. If the HO2S indicates the engine is running rich, the PCM corrects the rich condition by moving the short term fuel trim in the negative range (less fuel to correct for a rich combustion). If after a certain amount of time the short term fuel trim is still compensating for a rich condition, the PCM learns this and moves the long term fuel trim into the negative range to compensate and allow the short term fuel trim to return to a value near 0%. Input from the cylinder head temperature (CHT), intake air temperature (IAT), and mass air flow (MAF) sensors is required to activate the fuel trim system, which in turn activates the fuel system monitor. As the fuel system components age or otherwise change over the life of the vehicle, the adaptive fuel strategy learns deviations from stoichiometry while running in the closed loop. These learned corrections are stored in the KAM as long term fuel trim (LONGFT) corrections. As components continue to change beyond normal limits, or if a malfunction occurs, the LONGFT reaches a calibrated rich or lean limit and the adaptive fuel strategy is no longer allowed to compensate for additional fuel system changes. LONGFT correction at their limits, in conjunction with a calibrated deviation in short term fuel trim (SHRTFT), indicate a rich or lean fuel system malfunction. The fuel system monitor stores the appropriate DTC when a fault is detected as described below.

1. The HO2S detects the presence of oxygen in the exhaust and provides the PCM with the feedback indicating air/fuel ratio.
2. A correction factor is added to the fuel injector pulse width calculation and/or mass air flow calculation, according to the long and short term fuel trims as needed to compensate for variations in the fuel system.
3. When deviation in the parameter LAMBSE increases, air/fuel control suffers and emissions increase. When LAMBSE exceeds a calibrated limit and the fuel trim table has clipped, the fuel system monitor sets a DTC as follows: The DTC associated with the monitor detecting a lean shift in fuel system operation is P0171. The DTC associated with the monitor detecting a rich shift in fuel system operation is P0172.
4. The malfunction indicator lamp (MIL) is activated after a fault is detected on 2 consecutive drive cycles.

Typical Fuel System Monitor Entry Conditions

1. RPM range greater than idle.
2. Air mass range greater than 0.75 lb/min.
3. Purge duty cycle of 0%. Typical Fuel Monitor Malfunction Thresholds
4. Lean malfunction: LONGFT greater than 25%, SHRTFT greater than 5%.
5. Rich malfunction: LONGFT less than -25%, SHRTFT less than -10%.

Scheme 141

Heated Oxygen Sensor (HO2S) Monitor

The HO2S monitor is an onboard strategy designed to monitor the HO2S sensors for a malfunction or deterioration which can affect emissions. The fuel control or HO2S11 sensor is checked for proper output voltage and response rate (the time it takes to switch from lean to rich or rich to lean). HO2S12 sensor is used for catalyst monitoring. The HO2S sensors are also monitored for proper output voltage. Input is required from the cylinder head temperature (CHT), intake air temperature (IAT), mass airflow (MAF) and crankshaft position (CKP) sensors to activate the HO2S monitor. The fuel system monitor and misfire detection monitor must also complete successfully before the HO2S monitor is enabled.

1. The Escape Hybrid is a partial zero emission vehicle (PZEV) which uses 2 HO2S sensors. The front sensor (HO2S11) is the primary fuel control sensor. The last sensor downstream in the exhaust is used to monitor the light-off catalyst (HO2S12). The middle sensor in the exhaust stream does not provide any input to the powertrain control module (PCM).
2. The HO2S sensor senses the oxygen content in the exhaust flow and outputs a voltage between zero and 1.0 volt. Lean of stoichiometric (air/fuel ratio of approximately 14.7:1), the HO2S generates a voltage between zero and 0.45 volt. Rich of stoichiometric, the HO2S generates a voltage between 0.45 and 1.0 volt. The HO2S monitor evaluates the HO2S11 (fuel control) and HO2S12 (catalyst monitor) for proper function.
3. The time between HO2S switches is monitored after vehicle startup and during closed loop fuel conditions. Excessive time between switches or no switches since startup indicates a malfunction. Since lack of switching malfunctions can be caused by HO2S sensor malfunctions or by shifts in the fuel system, DTCs are stored that provide additional information for the lack of switching malfunction. Different DTCs indicate whether the sensor always indicates lean/disconnected (P2195), or always indicates rich (P2196). The PCM monitors the HO2S signal for high voltage, in excess of 1.1 volts and store a unique DTC (P0132). An over voltage condition is caused by a HO2S heater or battery power short to the HO2S signal line. A functional test of the HO2S12 sensor is done during normal vehicle operation. The peak rich and lean voltages are continuously monitored. Voltages that exceed the calibrated rich and lean thresholds indicate a functional sensor. If the voltages have not exceeded the thresholds after a long period of vehicle operation, the air/fuel ratio may be forced rich or lean in an attempt to get the HO2S12 sensor to switch. This situation normally occurs only with a green catalyst (less than 500 miles). If the sensor does not exceed the rich and lean peak thresholds, a malfunction is indicated. The HO2S12 signal is monitored for high voltage, in excess of 1.1 volts and stores a unique DTC (P0138). An over voltage condition is caused by a HO2S heater or battery power short to the HO2S signal line.
4. The MIL is activated after a fault is detected on two consecutive drive cycles.

The HO2S monitor DTCs can be categorized as follows

1. HO2S slow response rate-P0133.
2. HO2S circuit high voltage - P0132, P0138, P0144.
3. HO2S heater circuit malfunction - P0135, P0141, P0147.
4. HO2S heater current malfunction - P0053, P0054, P0055.
5. Downstream HO2S not running in on-demand self test - P1127.
6. HO2S lack of switching - P2195, P2196.
7. HO2S lack of switching (sensor indicates lean) - P2270, P2274.
8. HO2S lack of switching (sensor indicates rich) - P2271, P2275.

Scheme 142

Misfire Detection Monitor

The misfire detection monitor is an onboard strategy designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause. The misfire detection monitor is enabled only when certain base engine conditions are first satisfied. Input from the cylinder head temperature (CHT), mass airflow (MAF), and crankshaft position (CKP) sensors is required to enable the monitor. The misfire detection monitor is also carried out during an on-demand self-test.

Scheme 143

1. The PCM synchronized ignition spark is based on information received from the CKP sensor. The CKP signal generated is also the main input used in determining cylinder misfire.
2. The input signal generated by the CKP sensor is derived by sensing the passage of teeth from the crankshaft position wheel mounted on the end of the crankshaft.
3. The input signal to the PCM is then used to calculate the time between CKP edges and the crankshaft rotational velocity and acceleration. By comparing the accelerations of each cylinder event, the power loss of each cylinder is determined. When the power loss of a particular cylinder is sufficiently less than a calibrated value and other criteria is met, then the suspect cylinder is determined to have misfired.

Low Data Rate System

The LDR misfire monitor uses a low data rate crankshaft position signal, (one position reference signal at 10 degrees BTDC for each cylinder event). The PCM calculates the crankshaft rotational velocity for each cylinder from this crankshaft position signal. The acceleration for each cylinder can then be calculated using successive velocity values. The changes in overall engine RPM are removed by subtracting the median engine acceleration over a complete engine cycle. The resulting deviant cylinder acceleration values are used in evaluating misfire in generic misfire processing.

Generic Misfire Processing

The acceleration that a piston undergoes during a normal firing event is directly related to the amount of torque that cylinder produces. The calculated piston acceleration value(s) are compared to a misfire threshold that is continuously adjusted based on inferred engine torque. Deviant accelerations exceeding the threshold are conditionally labeled as misfires. The calculated deviant acceleration value(s) are also evaluated for noise. Normally, misfire results in a nonsymmetrical loss of cylinder acceleration. Mechanical noise, such as rough roads or high RPM/light load conditions, produce symmetrical acceleration variations. Cylinder events that indicate excessive deviant accelerations of this type are considered noise. Noise free deviant acceleration exceeding a given threshold is labeled a misfire. The number of misfires are counted over a continuous 200 revolutions and 1,000 revolutions period. The revolution counters are not reset if the misfire monitor is temporarily disabled such as for negative torque mode. At the end of the evaluation period, the total misfire rate and the misfire rate for each individual cylinder is computed. The misfire rate evaluated every 200 revolution period (Type A) and compared to a threshold value obtained from an engine speed/load table. This misfire threshold is designed to prevent damage to the catalyst due to sustained excessive temperature (1600°F). If the misfire threshold is exceeded and the catalyst temperature model calculates a catalyst mid-bed temperature that exceeds the catalyst damage threshold, the MIL blinks at a 1 Hz rate while the misfire is present. If the threshold is again exceeded on a subsequent driving cycle, the MIL is illuminated. The misfire rate is evaluated every 1,000 revolutions period and compared to a single (Type B) threshold value to indicate an emission threshold malfunction, which can be either a single 1,000 over-revolutions event from startup or 4 subsequent 1,000 over-revolutions events on a drive cycle after start-up. DTC P0316 is set if the Type B malfunction threshold is exceeded during the first 1,000 revolutions after engine startup. This DTC is stored in addition to the normal P03xx DTC that indicates the misfiring cylinder(s).

Profile Correction

The profile correction software learns the crankshaft tooth spacing under defueled engine conditions. The profile correction requires the engine to be shut down either at key off, or during normal vehicle operation, after the keep alive memory (KAM) reset. The learned corrections improve the high RPM capability of the monitor. The misfire monitor is not active until a profile is learned. The profile correction software learns and corrects for mechanical inaccuracies in the crankshaft position wheel tooth spacing. Since the sum of all the angles between the crankshaft teeth must equal 360 degrees, a correction factor can be calculated for each misfire sample interval that makes all the angles between individual teeth equal. To prevent any fueling or combustion differences from affecting the correction factors, learning is done during engine shutdown. In order to minimize learning time for profile correction factors, the correction factors are learned after an engine shutdown is commanded and fuel is disabled while the generator motor spins the engine. In order to protect the traction battery, and provide vehicle starting, the following conditions must be met to extend the shutdown: traction battery temperature and state of charge (SOC) must be within operational limits. This condition occurs either when the key is turned to the OFF position (typically 1 key off induced engine shutdown), or when the normal operating strategy shuts the engine down (typically multiple shutdown events during normal operation). During this shutdown, the generator motor spins the engine at approximately 1,100 RPM, while delta time intervals are captured for computation of the correction factors. Average profile correction factors are calculated for each of the 4 combustion intervals over approximately 15 engine cycles. This procedure occurs once per KAM reset during the life of the vehicle. Since inaccuracies in the wheel tooth spacing can produce a false indication of misfire, the misfire monitor is not active until the corrections are learned. In the event of the 12 volt battery disconnection or loss of KAM the correction factors are lost and must be relearned. The software may be unable to learn a profile if the instantaneous profile calculations vary by more than a specified tolerance from the mean values. In this case a DTC P0315 is set. Typical profile correction learning entry conditions are: engine in fuel disabled mode for 4 engine cycles, engine speed between 800 and 1,750 RPM, maximum RPM change during profile correction is 600 RPM, vehicle speed between 0 and 48 km/h (0 and 30 mph), the traction battery voltage above 216 volts, the traction battery temperature above -15° C (5° F), and the traction battery power discharge limit above 12 kW.

Positive Crankcase Ventilation (PCV) System Monitor

The PCV monitor consists of a modified PCV system design. The PCV valve is installed into the rocker cover using a quarter-turn camlock design to prevent accidental disconnection. High retention force molded plastic lines are used from the PCV valve to the intake manifold. The diameter of the lines and the intake manifold entry fitting are increased so that inadvertent disconnection of the lines after a vehicle is repaired either causes an immediate engine stall or does not allow the engine to be restarted. In the event that the vehicle does not stall if the line between the intake manifold and PCV valve is inadvertently disconnected, the vehicle has a large vacuum leak that causes the vehicle to run lean at idle. This illuminates the MIL after 2 consecutive driving cycles and stores one or more of the following DTCs: lack of heated oxygen sensor (HO2S) switches, bank 1 (P2195), fuel system lean, bank 1 (P0171).

For additional PCV information, refer to POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM .

Thermostat Monitor

The thermostat monitor is designed to verify proper thermostat operation. This monitor is executed once per drive cycle and has a monitor run duration of 300 - 800 seconds. If a malfunction occurs, a diagnostic trouble code (DTC) P0128 will be set and the malfunction indicator lamp (MIL) will be illuminated.

The monitor checks the engine coolant temperature by monitoring the cylinder head temperature (CHT) sensor to warm up in a predictable manner when the engine is generating sufficient heat. A timer is incremented while the engine is at moderate load and the vehicle speed is above a calibrated limit. The target timer value is based on the ambient air temperature at start-up. If the timer exceeds the target time and the CHT has not warmed up to the target temperature, a malfunction is indicated. The test runs if the start-up intake air temperature from the intake air temperature (IAT) sensor is at or below the target temperature. A 2 hour engine off soak time is also required to enable the monitor and to prevent erasing of any pending DTC during a hot soak. This soak time feature also prevents false passes of the monitor when the engine coolant temperature rises after the engine is turned off during a short engine off soak period.

The target temperature is calibrated to the thermostat regulating temperature minus 11 °C (20 °F). For a typical 90 °C (195 °F) thermostat, the warm-up temperature would be calibrated to 79 °C (175 °F).

Scheme 144

1. Inputs: CHT, IAT, engine load from mass air flow (MAF) sensor and vehicle speed input. Typical monitor entry conditions: Vehicle speed greater than 24 km/h (15 mph). Intake air temperature at start-up is between -7 °C (20 °F) and target thermostat temperature. Engine load greater than 30%. Engine off (soak) time greater than 2 hours.
2. Output: MIL

Malfunction Indicator Lamp (MIL)

The MIL alerts the driver that the powertrain control module (PCM) has detected an on board diagnostics (OBD) emission-related component or system fault. When this occurs, an OBD diagnostic trouble code (DTC) is set.

1. The MIL is located on the instrument cluster and is labeled as international standardization organization engine symbol.
2. Power is supplied to the MIL whenever the key is in the ON or START position.
3. The MIL will remain on in the ON/START mode as a bulb check during the instrument cluster prove out for approximately 4 seconds.
4. If the MIL remains on after the bulb check: The PCM illuminates the MIL for an emission related concern and a DTC will be present. The instrument cluster will illuminate the MIL if the PCM does not send a control message to the instrument cluster. The PCM is operating in the hardware limited operation strategy (HLOS).
5. If the MIL remains off (during the bulb check): The bulb is damaged. Instrument cluster wiring concern.
6. To turn off the MIL after a repair, a reset command from the diagnostic tool must be sent, or 3 consecutive drive cycles must be completed without a fault.
7. For any MIL concern, GO to Quick Test «QT1 CARRY OUT DATA LINK DIAGNOSTICS TEST»(ref-235205-S26123991482006061500000)
8. If the MIL blinks at a steady rate, a severe misfire condition may exist.

Scheme 145

Transaxle Comprehensive Component Monitor (CCM)

The transaxle CCM monitors for malfunctions in the transaxle system. The transaxle CCM monitors internal and external electronic and mechanical components, as well as internal and external circuitry which provides input or output signals to or from the transaxle control module (TCM). The circuitry and components are typically monitored for circuit continuity and proper range of values. Where feasible, they are also checked for rationality.

The transaxle CCM covers many components and circuits and tests them in various ways depending on the hardware, function, and type of signal. For example, input and output signals are typically checked for opens, shorts, and in-range failures. This type of monitoring is carried out continuously. Some TCM input and output signals may rely on rationality checks - checking to see if the input or output value makes sense for the current system operating conditions. These types of tests may require monitoring several components and can only be carried out under appropriate test conditions.

The following components and circuitry are monitored by the transaxle CCM. The list includes the components or other TCM inputs, corresponding circuitry, and the type of electrical test carried out.

Transaxle fluid temperature sensor and circuit

1. open circuit test
2. short circuit to ground test
3. short circuit to power test
4. in-range failure test

Motor and generator coil temperature sensors and circuits

1. open circuit test
2. short circuit to ground test
3. short circuit to power test
4. in-range failure test

Motor and generator inverter temperature sensors and circuits

1. open circuit test
2. short circuit to ground test
3. short circuit to power test
4. in-range failure test

Motor and generator current sensors and circuits

1. open circuit test
2. short circuit to ground test
3. short circuit to power test
4. in-range failure test
5. rationality test

Immediate shutdown 1 and 2 circuits

1. open circuit test
2. short circuit to ground test
3. rationality test

Motor and generator shutdown circuits

1. open circuit test
2. short circuit to ground test
3. short circuit to power test
4. rationality test

Clean tachometer output circuit

1. open circuit test
2. short circuit to ground test
3. short circuit to power test
4. rationality test

Motor and generator inverters

1. open circuit test
2. short circuit to ground test
3. short circuit to power test
4. in-range failure test
5. rationality test
6. over voltage test

High voltage interlock circuit

1. open circuit test

In addition to the electrical checks, the transaxle CCM also monitors the ignition voltage to the TCM for over voltage and under voltage conditions, traction motor and generator over-speed conditions, park pawl and one-way clutch mechanical damage, and an abnormal shutdown condition. The controller area network (CAN) messages such as revolutions per mile, generator mode, vehicle mode, total torque desired, engine speed desired, and estimated engine torque are monitored for out of range or missing status.

When any monitored component fails and no longer operates within manufacturer's specifications, the TCM stores the diagnostic trouble code (DTC) and illuminates the caution lamp or hazard lamp. When the initial malfunction is detected the TCM stores the temporary DTC and record the freeze frame data. This temporary DTC is erased on the third vehicle restart after 2 consecutive detection trips with no malfunction. However, if the malfunction is still present after 2 consecutive detection trips, the caution lamp or hazard lamp may be illuminated. Once the caution lamp or hazard lamp are illuminated, 3 consecutive detection trips without malfunction are required to extinguish them. Forty warm-up cycles without malfunction are required to erase the DTC from the TCM memory.

In addition to the DTC stored, the TCM stores freeze frame data in the electrically erasable programmable read only memory (EEPROM). The following parameters are recorded when freeze frame data is stored

1. DTC item number
2. engine speed
3. transaxle fluid temperature
4. traction motor and generator speed
5. highest traction motor and generator inverter temperature
6. traction motor and generator coil temperature
7. desired total torque
8. desired traction motor and generator torque
9. shift position

The freeze frame data is accessible with the diagnostic tool to assist in diagnosing the vehicle.

Modifications to OBD Vehicles

Modifications or additions to the vehicle may cause incorrect operation of the OBD system. Non-factory anti-theft systems, cellular telephones, and radios must be carefully installed. Do not install these devices by tapping into or running wires close to the powertrain control system wires or components.

Engine RPM/Vehicle Speed Limiter

The powertrain control module (PCM) disables some or all of the fuel injectors whenever an engine RPM or vehicle over-speed condition is detected. The purpose of the engine RPM or vehicle speed limiter is to prevent damage to the powertrain. The vehicle exhibits a rough running engine condition, and the PCM stores continuous diagnostic trouble code (DTC) P1270. Once the driver reduces the over-speed condition, the engine returns to the normal operating mode. No repair is required. However, the technician should clear the DTC and inform the customer of the reason for the DTC.

Excessive wheel slippage may be caused by sand, gravel, rain, mud, snow, ice, or excessive and sudden increase in RPM while in NEUTRAL or while driving.

Fail-Safe Cooling Strategy

The fail-safe cooling strategy is activated by the PCM only in the event that an overheating condition has been identified. This strategy provides engine temperature control when the cylinder head temperature exceeds certain limits The cylinder head temperature is measured by the cylinder head temperature (CHT) sensor. For additional information about the CHT sensor, refer to CYLINDER HEAD TEMPERATURE (CHT) SENSOR .

A cooling system failure such as low coolant or coolant loss could cause an overheating condition. As a result, damage to major engine components may occur. Along with a CHT sensor, the fail-safe cooling strategy is used to prevent damage by allowing air-cooling of the engine. This strategy allows the vehicle to be driven safely for a short period of time when an overheat condition exists.

The engine temperature is controlled by varying and alternating the number of disabled fuel injectors. This allows all cylinders to cool. When the fuel injectors are disabled, their respective cylinders work as air pumps, and this air is used to cool the cylinders.

On the Escape Hybrid, the PCM provides a fail-safe cooling status information to the instrument cluster through the controller area network (CAN). The PCM sends a CAN message signal to the cluster indicating what fail-safe cooling mode the vehicle is in. There are 3 levels of this message, which are: normal operating mode, fail-safe mode 1 and fail-safe mode 2. The cluster turns the red temperature indicator OFF if normal operating mode is received, turns the red temperature indicator ON if it receives a fail-safe mode 1 message, and it flashes the red temperature indicator if it receives a fail-safe mode 2 message. During failsafe mode 1 the PCM sets a DTC P1285 and during fail-safe mode 2 the PCM sets a DTC P1299.

Note. The instrument cluster red temperature indicator is also used by the motor electronic cooling loop and may be illuminated by an over temperature condition in that subsystem. The motor electronic cooling loop includes the generator, DC/DC converter and the traction motor. The motor electronic cooling loop also contains a motor electronic coolant temperature (MECT) sensor and motor electronic coolant pump (MECP) to circulate the coolant. Refer to MOTOR ELECTRONICS COOLANT TEMPERATURE (MECT) SENSOR for MECT information and to MOTOR ELECTRONICS COOLING PUMP (MECP) for MECP information.

Failure Mode Effects Management

Failure mode effects management (FMEM) is an alternate system strategy in the PCM designed to maintain engine operation if one or more sensor inputs fail.

When a sensor input is perceived to be out-of-limits by the PCM, an alternative strategy is initiated. The PCM substitutes a fixed value and continues to monitor the incorrect sensor input. If the suspect sensor operates within limits, the PCM returns to the normal engine operational strategy.

All FMEM sensors display a sequence error message on the diagnostic tool. The message may or may not be followed by key on engine off (KOEO) or continuous memory DTCs when attempting key on engine running (KOER) self-test mode.

Flash Electrically Erasable Programmable Read Only Memory (EEPROM)

The flash EEPROM is an integrated circuit (IC) within the PCM. This IC contains the software code required by the PCM to control the powertrain. One feature of the EEPROM is that it can be electrically erased and then reprogrammed without removing the PCM from the vehicle. If a software change is required to the PCM, the module no longer needs to be replaced, but can be reprogrammed using a diagnostic tool.

Fuel Trim

Short Term Fuel Trim

If the heated oxygen sensors (HO2S) are warmed up and the PCM determines that the engine can operate near stoichiometric air/fuel ratio (14.7:1 for gasoline), the PCM goes into closed loop fuel control mode. Since an oxygen sensor can only indicate rich or lean, the fuel control strategy must constantly adjust the desired air/fuel ratio rich and lean to get the oxygen sensor to switch around the stoichiometric point. If the times between switches are the same, then the system is actually operating at stoichiometry. The desired air/fuel control parameter is called short term fuel trim (SHRTFT1) where stoichiometry is represented by 0%. Richer (more fuel) is represented by a positive number and leaner (less fuel) is represented by a negative number. Normal operating range for short term fuel trim is +/- 25%. Sometimes the calibration can run the system slightly lean or rich of stoichiometry. This practice is referred to as using bias. For example, the fuel system can be biased slightly rich during closed loop fuel to help reduce NOx.

Values for SHRTFT1 may change a great deal on a diagnostic tool when the engine is operated at different RPM and load points. This is because SHRTFT1 reacts to fuel delivery variability that can change as a function of engine RPM and load. Short term fuel trim values are not retained after the engine is turned off.

Long Term Fuel Trim

While the engine is operating in closed loop fuel, the short term fuel trim corrections can be learned by the PCM as long term fuel trim (LONGFT1) corrections. These corrections are stored in keep alive memory (KAM) in tables that are referenced by engine speed and load. Learning the corrections in KAM improves both open loop and closed loop air/fuel ratio control. Advantages include

1. Short term fuel trim does not have to generate new corrections each time the engine goes into closed loop.
2. Long term fuel trim corrections can be used both while in open loop and closed loop modes.

Long term fuel trim is represented as a percentage, just like short term fuel trim, however it is not a single parameter. There is a separate long term fuel trim value that is used for each RPM/load point of engine operation. Long term fuel trim corrections may change depending on the operating conditions of the engine (RPM and load), ambient air temperature, and fuel quality (% alcohol or oxygenates). When viewing the LONGFT1 PID, the values may change a great deal as the engine is operated at different RPM and load points. The LONGFT1 PID displays the long term fuel trim correction that is currently being used at that RPM/load point.

High Speed Control Area Network (CAN)

The high speed CAN is based on SAE J2284, ISO-11898 and is a serial communication language protocol used to transfer messages (signals) between electronic modules or nodes. Two or more signals can be sent over one CAN network circuit allowing 2 or more electronic modules or nodes to communicate with each other. This communication network operates at 500 kilobytes per second (kb/sec) and allows the electronic modules to share their information messages.

Included in these messages is diagnostic data that is output over the CAN high (+) and CAN low (-) lines to the data link connector (DLC). The diagnostic data such as self-test DTCs or PIDs can be accessed with the diagnostic tool. Information on diagnostic tool equipment is described in DIAGNOSTIC METHODS .

Multiplexing

The increased number of modules on the vehicle necessitates a more efficient method of communication. Multiplexing is a method of designating a system for sending 2 or more signals simultaneously over a single circuit. In an automotive application, multiplexing is used to allow 2 or more electronic modules to communicate simultaneously over a single media. Typically this media is a twisted pair of wires. The information or messages that can be communicated on these wires consists of commands, mode status, or data. The advantage of using multiplexing is to reduce the weight of the vehicle by reducing the number of redundant components and electrical wiring.

Multiplexing Implementation

The multiplexing can be implemented by using a communication language protocol such as controller area network (CAN). Vehicle network protocols such as CAN allow module-to-module communication to become possible. This communication allows several modules to share information within the vehicle network. The Escape Hybrid uses a high-speed CAN protocol for its powertrain communication. For more information about the entire communication network, refer to MODULE COMMUNICATIONS NETWORK , Module Communications.

Vehicle Speed From The Anti-Lock Brake System (ABS) Module

The ABS module calculates wheel speed from the front 2 wheel speed sensors and sends this information to the PCM through the communication network.

Vehicle Speed From The Transaxle Control Module (TCM)

The TCM calculates traction motor speed from the traction motor shaft speed sensor and combines it with (PCM stored) tire size and axle ratio data to determine vehicle speed. This calculation is than sent to the PCM over the communication network.

Vehicle Speed From Engine And Generator Speed

The TCM calculates generator speed from the generator shaft speed sensor and sends this information to the PCM. The PCM combines input information from the generator speed and engine speed along with tire size and gear ratio to calculate a vehicle speed.

The PCM strategy then cross checks all the inputs to determine if they agree with one another. If there is a discrepancy between inputs, a vehicle speed fault flag is set in the PCM and a DTC is stored.

Fuel Pump Driver Module (FPDM)

The FPDM receives a duty cycle signal from the powertrain control module (PCM) and controls the fuel pump operation in relation to this duty cycle. This results in variable speed fuel pump operation. The FPDM sends diagnostic information to the PCM on the fuel pump monitor circuit. For additional information, refer to FUEL PUMP (FP) for Fuel Pump and FUEL PUMP MONITOR (FPM) for Fuel Pump Monitor.

Integrated Electronic Ignition (EI) System

The EI system consists of a crankshaft position (CKP) sensor, ignition coils, connecting wiring, and PCM. The coil on plug (COP) integrated EI system uses a separate coil for each spark plug and each coil is mounted directly onto the plug. The COP integrated EI system eliminates the need for spark plug wires, but requires input from the camshaft position (CMP) sensor.

Powertrain Control Module (PCM)

The center of the electronic engine control (EEC) system is a microprocessor called the PCM. The PCM receives input from sensors and other electronic components. Based on information received and programmed into its memory, the PCM generates output signals to control various relays, solenoids, and actuators. The Ford Escape Hybrid uses a 150 pin PCM which has 3 separate electrical harness connectors.

Scheme 146

IDENTIFYING PCM CONNECTOR/PINS

Powertrain Control Module (PCM) Keep Alive Memory (KAM)

The PCM stores information in keep alive RAM (a memory integrated circuit chip) about vehicle operating conditions, and then uses this information to compensate for component variability. KAM remains powered when the key is off so that this information is not lost.

Vehicle Buffered Power (VBPWR)

The VBPWR is a PCM supplied power source that supplies regulated voltage (10 to 14 volts) to vehicle sensors that run off 12 volts but cannot withstand VPWR voltage variations. It is regulated to VPWR minus 1.5 volts and is voltage limited to protect the sensors.

Vehicle Power (VPWR)

When the key is turned to the ON or START position, battery positive voltage (B+) is applied to the coils of the EEC power relay and power sustain relay (PSR). Since the other end of the coils are wired to ground, this energizes the coils and closes the contacts of the EEC power relay and PSR. VPWR is now supplied to the PCM and the EEC system as VPWR. When the key is turned to the OFF position, the PCM keeps the PSR energized until the normal power down sequence is completed. Refer to POWER SUSTAIN RELAY (PSR) for additional information.

Vehicle Reference (VREF) Voltage

The VREF is a positive voltage (about 5.0 volts) that is output by the PCM. This is a consistent voltage that is used by the 3-wire sensors.

Mass Air Flow Return (MAF RTN)

The MAF RTN is a dedicated analog signal return from the mass air flow (MAF) sensor. It serves as a ground offset for the analog voltage differential input by the MAF sensor to the PCM.

Signal Return (SIG RTN)

The SIG RTN is a dedicated ground circuit used by most EEC sensors and some other inputs.

Power Ground (PWR GND)

The PWR GND is an electric current path return for VPWR voltage circuit. The purpose of the PWR GND is to maintain sufficient voltage at the PCM.

Gold Plated Pins

Note. Damaged gold terminals should only be replaced with new gold terminals.

Some engine control hardware has gold plated pins on the connectors and mating harness connectors to improve electrical stability for low current draw circuits and to enhance corrosion resistance.

Accelerator Pedal Position (APP) Sensor

For information on the APP sensor, refer to ACCELERATOR PEDAL POSITION (APP) SENSORS .

Air Conditioning Cycling Switch (ACCS) Circuit

The ACCS circuit to the powertrain control module (PCM) provides a voltage signal which indicates when A/C is requested. When the A/C function selector switch is turned on, voltage is supplied to the ACCS circuit at the PCM. Refer to SYSTEM WIRING DIAGRAMS for vehicle wiring.

If the ACCS signal is not received by the PCM, the PCM does not allow the A/C to operate.

Air Conditioning Evaporative Temperature (ACET) Sensor

The ACET sensor monitors the evaporator air discharge temperature. The ACET sensor is a thermistor device in which resistance changes with temperature. The ACET sensor is used to more accurately control A/C clutch cycling, improve defrost/demist performance and reduce A/C clutch cycling. The electrical resistance of a thermistor decreases as the temperature increases, and the resistance increases as the temperature decreases. The PCM sources a low current 5 volts on the ACET circuit. With SIG RTN also connected to the ACET sensor, the varying resistance affects the voltage drop across the sensor terminals. As the A/C evaporator air temperature changes, the varying resistance of the ACET sensor changes the voltage the PCM detects.

ACET SENSOR SPECIFICATION CHART

Air Conditioning (A/C) Full Demand Switch

The A/C full demand switch circuit provides a voltage signal to the PCM which indicates the MAX A/C, DEFROST, or FLOOR/DEFROST mode is requested. If the engine is shut down during normal engine operation the PCM restarts it when A/C full demand is selected. The engine will remain running when the A/C full demand switch is selected allowing the A/C compressor to circulate the refrigerant for the passenger compartment.

Air Conditioning (A/C) High Pressure Switch

The A/C high pressure switch is used for additional A/C system pressure control. For refrigerant containment control, the normally closed high pressure contacts open at a predetermined A/C pressure. This results in the A/C turning off, preventing the A/C pressure from rising to a level that would open the A/C high pressure relief valve.

For fan control, the normally open medium pressure contacts close at a predetermined A/C pressure. This grounds the ACPSW circuit input to the PCM. The PCM then turns on the high speed fan to help reduce the pressure.

For additional information, refer to AIR CONDITIONING and/or SYSTEM WIRING DIAGRAMS .

Air Conditioning (A/C) Low Pressure Switch

The A/C low pressure switch is used for additional A/C system pressure control. This normally closed switch opens when the refrigerant pressure drops below 152 kPa (22 psi). This results in the A/C turning off, preventing the evaporator from freezing.

Air Conditioning (A/C) Recirculation Switch

The A/C recirculation switch circuit provides a voltage signal to the PCM which indicates the A/C recirculation mode is requested. The PCM requests the traction battery cooling system to enter the recirculation mode when the PCM receives the A/C recirculation signal.

Battery Power Off (BPO) Request

The traction battery control module (TBCM) checks the inertia fuel shut off switches, the high voltage interlock (HVIL) circuit, and the traction battery lid tamper switch for an open circuit fault condition. If the open circuit fault condition is not detected, the TBCM continuously toggles the BPO output, typically generating a 2 Hz pulse width modulated signal to the powertrain control module (PCM). The TBCM also broadcasts a normal message to the PCM over the communication link. When the TBCM detects a fault condition, it changes the pulse width modulated signal frequency to 6 Hz at 50% duty cycle and broadcasts an error message to the PCM over the communication link. The error message and the 6 Hz frequency indicate to the PCM that the traction battery opens its contactors in 1 second. After the contactors are open the PCM carries out a normal power down sequence to the transaxle control module (TCM) and DC/DC converter.

Brake Pedal Position (BPP) Switch

The BPP switch is a normally open switch that, when closed, sends a signal to the PCM when the brake pedal is applied. The PCM strategy uses this signal input to aid the PCM in determining the correct function and operation of the vehicle speed control, the electronic throttle control (ETC), and the transaxle and regenerative braking systems. The BPP switch is hard wired to the PCM and supplies positive battery voltage (+12 volts) when the brake pedal is applied. When the brake pedal is released, the BPP switch opens and no battery voltage input is sent to the PCM.

Brake Pedal Switch (BPS)

The BPS used for vehicle speed control deactivation is a normally closed switch, which supplies positive battery voltage (+12 volts) to the PCM when the brake pedal is released. When the brake pedal is applied, the normally closed switch opens and power is removed from the BPS circuit to the PCM.

The normally closed BPS along with the normally open BPP switch is used by the PCM strategy for a brake pedal rationality test. The PCM strategy looks for each switch to change states when the brake pedal is applied and released. If a failure occurs in one or both of the brake pedal inputs a DTC P1572 is set and the PCM misfire OBD monitor is disabled.

Camshaft Position (CMP) Sensor

The CMP sensor is a variable reluctance sensor that detects the position of the camshaft. The CMP sensor identifies when piston number 1 is on its compression stroke. A signal is then sent to the PCM and used for synchronizing the firing of sequential fuel injectors. The PCM also uses the CMP signal to select the proper ignition coil to fire. The input circuit to the PCM is referred to as the CMP input or circuit.

Scheme 147

Crankshaft Position (CKP) Sensor

The CKP sensor is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKP is the primary sensor for ignition information to the PCM. The pulse wheel has a total of 35 teeth spaced 10 degrees apart with one empty space for a missing tooth. By monitoring the pulse wheel, the CKP sensor signal indicates the crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP sensor is also able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to a fixed reference. The PCM also uses the CKP signal to determine if a misfire has occurred by measuring rapid decelerations between pulse wheel teeth.

Scheme 148

Cylinder Head Temperature (CHT) Sensor

The CHT sensor is a thermistor device in which the resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.

Thermistor-type sensors are considered passive sensors. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow.

The CHT sensor is installed in the aluminum cylinder head and measures the metal temperature. The CHT sensor can provide complete engine temperature information and can be used to infer coolant temperature. If the CHT sensor conveys an overheating condition to the PCM, the PCM then initiates a fail-safe cooling strategy based on information from the CHT sensor. A cooling system failure such as low coolant or coolant loss could cause an overheating condition. As a result, damage to major engine components could occur. Using both the CHT sensor and fail-safe cooling strategy, the PCM prevents damage by allowing air cooling of the engine and limp home capability. For additional information, refer to FAIL-SAFE COOLING STRATEGY .

Scheme 149

DC/DC Fault

The DC/DC fault (DCF) signal is an input to the PCM from the DC/DC converter. This signal is low under normal conditions and switches high when a fault exists within the DC/DC converter cooling system, the high voltage power supply to the DC/DC converter, or the low voltage output system. The PCM disables or limits the operation of the DC/DC converter by the DC/DC enable circuit (DCE), when a DCF fault is indicated. For additional information on DCF, refer to DC/DC CONVERTER .

Electronic Throttle Position (TP) Sensor

For information on the electronic TP sensor, refer to the description of the TORQUE BASED ELECTRONIC THROTTLE CONTROL (ETC) .

Fuel Pump Monitor (FPM)

The fuel pump driver module (FPDM) communicates diagnostic information to the PCM through the FPM circuit. This information is sent by the FPDM as a duty cycle signal. The 3 duty cycle signals that may be sent are listed in the following table.

FUEL PUMP DRIVER MODULE (FPDM) DUTY CYCLE SIGNALS

Fuel Tank Pressure (FTP) Sensor

For information on the FTP sensor, refer to the description of the EVAPORATIVE EMISSION (EVAP) SYSTEM .

Fuel Rail Pressure Temperature (FRPT) Sensor

The FRPT sensor measures the pressure and temperature of the fuel in the fuel rail and sends these signals to the PCM. The sensor uses the intake manifold vacuum as a reference to sense the pressure difference between the fuel rail and the intake manifold. A fuel return line to the fuel tank is not used in this type of fuel system. The relationship between fuel pressure and fuel temperature is used to determine the possible presence of fuel vapor in the fuel rail. Both pressure and temperature signals are used to control the speed of the fuel pump. The speed of the fuel pump maintains fuel rail pressure by keeping fuel in its liquid state. The dynamic range of the fuel injectors increases because of the higher rail pressure, which allows the injector pulse width to decrease.

Scheme 150

Heated Oxygen Sensor (HO2S)

The HO2S detects the presence of oxygen in the exhaust and produces a variable voltage according to the amount of oxygen detected. A high concentration of oxygen (lean air/fuel ratio) in the exhaust produces a voltage signal less than 0.4 volt. A low concentration of oxygen (rich air/fuel ratio) produces a voltage signal greater than 0.6 volt. The HO2S provides feedback to the PCM indicating air/fuel ratio in order to achieve a near stoichiometric air/fuel ratio of 14.7:1 during closed loop engine operation. The HO2S generates a voltage between 0.0 and 1.1 volts.

Embedded with the sensing element is the HO2S heater. The heating element heats the sensor to temperatures of 800°C (1400°F). At approximately 300°C (600 °F) the engine can enter closed loop operation. The VPWR circuit supplies voltage to the heater and the PCM turns on the heater by providing the ground when the proper conditions occur. The heater allows the engine to enter closed loop operation sooner. The use of this heater requires that the HO2S heater control be duty cycled to prevent damage to the heater.

Scheme 151

Ignition Switch Position Run (ISP-R)

The ISP-R provides the PCM with a VBAT input signal from the ignition switch, indicating that the key is either in the ON or START position. When the operator turns the key to the OFF or ACC position, the internal combustion engine immediately ceases to provide power. The PCM coordinates the power down sequence by controlling the power sustain circuit and issuing the proper commands to shut down the electrical system in an orderly fashion, refer to the NORMAL POWER DOWN SEQUENCE . The PCM maintains power to the transaxle control module (TCM) through the power sustain circuit until the power down sequence is complete. The traction battery control module (TBCM) is always powered directly from the low voltage battery which permits wake-up when the vehicle is off.

Ignition Switch Position Run/Start (ISP-RS)

The ISP-RS provides the PCM with a VBAT input signal from the ignition switch, indicating the key is in the START position.

Intake Air Temperature (IAT) Sensor

The IAT sensor is integrated into the mass air flow (MAF) sensor. It is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.

A thermistor-type sensor is considered a passive sensor. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in the total current flow.

Voltage that is dropped across a fixed resistor in a series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.

The IAT provides air temperature information to the PCM. The PCM uses the air temperature information as a correction factor in the calculation of fuel, and ignition timing.

Scheme 152

Knock Sensor (KS)

The KS is a tuned accelerometer on the engine which converts engine vibration to an electrical signal. The PCM uses this signal to determine the presence of engine knock and to retard spark timing.

Manifold Absolute Pressure (MAP) Sensor

The MAP sensor uses a piezo-resistive silicon sensing element to provide a voltage proportional to the absolute pressure in the intake manifold.

The MAP sensor is part of the exhaust gas recirculation (EGR) system. The PCM uses information from the MAP sensor, throttle position (TP) sensor, mass air flow (MAF) sensor, cylinder head temperature (CHT) sensor and crankshaft position (CKP) sensor to determine how much exhaust gas is introduced into the intake manifold.

Scheme 153

Mass Air Flow (MAF) Sensor

The MAF sensor uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wire causes it to cool. This hot wire is maintained at 200°C (392°F) above the ambient temperature as measured by a constant cold wire. If the hot wire electronic sensing element must be replaced, then the entire assembly must be replaced. Replacing only the element may change the air flow calibration.

The current required to maintain the temperature of the hot wire is proportional to the volume of air flow. The MAF sensor then outputs an analog voltage signal to the PCM proportional to the intake air mass. The PCM calculates the required fuel injector pulse width in order to provide the desired air/fuel ratio.

The MAF sensor is located between the air cleaner and the throttle body inside the air cleaner assembly.

Scheme 154

Motor Electronics Coolant Temperature (MECT) Sensor

The MECT sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature. A thermistor-type sensor is considered a passive sensor. A passive sensor is connected to a voltage divider network so that varying the resistance of the passive sensor causes a variation in total current flow. Voltage that is dropped across a fixed resistor in a series with the sensor resistor determines the voltage signal at the PCM. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor. The MECT provides motor electronics coolant system temperature information to the PCM. The PCM uses this information for determining when to activate the cooling system fans and indicate over-temperature.

Scheme 155

Restraint Deployment Indicator (RDI)

The RDI is an input signal sent from the restraints control module (RCM) to the PCM indicating an air bag deployment. The signal is a zero to VPWR 50% duty cycle, that is .83 Hz for a normal condition, and 5 Hz indicates a deployment event has occurred. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .

Speed Control Switch

For information on the speed control switch, refer to SPEED CONTROL .

TR Sensor and PCM Interface

The TR sensor is a linear potentiometer device that provides the PCM with a percentage of input voltage proportional to the rotational angle of the sensor shaft. The TR sensor consists of

1. (3) independent (TR-A1, TR-A2 and TR-A3) signals.
2. (2) 5 volt reference (TR-VREF1 and TR-VREF2) lines.
3. (2) signal return (TR-RTN1 and TR-RTN2) lines.

Scheme 156

The TR-A1 signal has a negative voltage slope, meaning the voltage decreases when the sensor angle increases. The typical TR voltage ranges from approximately 4.5 volts in the PARK position to approximately 1 volt in the LOW gear position. The TR-A2 and the TR-A3 signals both have a positive voltage slope. Voltages increase as the sensor angle increases. The typical voltage for the TR-A2 and the TR-A3 range from about 0.6 volts in the PARK position to about 3.5 volts in the LOW gear position.

The TR-VREF circuits are bussed together internal to the TR sensor, and both TR-RTN circuits are bussed together in the TR sensor. One of the TR-VREF and one of the TR-RTN circuits are dedicated signals from the PCM. This design of redundant signals protects against an open circuit condition.

Scheme 157

If the PCM detects a fault condition in one of TR signal inputs, it uses the other 2 TR signals to determine what gear the driver selects. If the PCM detects 2 or more TR signals that are invalid, the PCM

1. allows the vehicle to travel in DRIVE position or LOW gear position if the vehicle was driving forward at a significant speed when the fault was detected.
2. allows the vehicle to travel in REVERSE gear if the vehicle was driving backwards at a significant speed when the fault was detected.
3. broadcasts gear mode - NEUTRAL over the communication link when vehicle speed decreases to 8 km/h (5 mph).
4. sets the diagnostic trouble code (DTC) and illuminates the indicator light.

Active Mount Control

The Escape Hybrid is equipped with a semi-active, vacuum operated, electronically controlled engine mount. The semi-active mount is located on the bulkhead side of the engine. The semi-active mount has 2 fluid filled chambers with a variable orifice between both chambers. This mount changes state based on the engine speed that is calibrated in the PCM. When the engine RPM is at or below a calibrated value, vacuum is applied to the mount, which increases the size of the orifice, making the mount softer. When the engine RPM is greater than the calibrated engine RPM, the vacuum supply is closed and the vacuum in the mount is bled to atmospheric pressure, which decreases the size of the orifice, making the mount firmer.

Scheme 158

Air Conditioning (A/C) Clutch Relay

The A/C clutch relay (may be referred to as the wide open throttle A/C cutoff relay) is wired normally open. There is no direct electrical connection between the A/C switch or electronic automatic temperature control (EATC) module and the A/C clutch. The PCM receives a signal indicating that A/C is requested. When A/C is requested, the PCM checks other A/C related inputs that are available. If these inputs indicate A/C operation is OK, and the engine conditions are OK (coolant temperature, engine RPM, throttle position), the PCM grounds the WAC output, closing the relay contacts and sending voltage to the A/C clutch.

Air Conditioning (A/C) Refrigerant Distribution Valve (ACRDV)

The ACRDV is a PCM controlled solenoid which provides a regulated control of refrigerant flow to the passenger compartment loop. The PCM opens or closes the ACRDV based on the passenger compartment A/C request. The ACRDV is a normally closed valve, preventing the refrigerant flow. When the passenger compartment A/C is requested ON, the PCM provides a ground path to the solenoid which opens the ACRDV.

Scheme 159

Canister Vent Solenoid

For information on the canister vent solenoid, refer to the description of the CANISTER VENT (CV) SOLENOID .

Clean Tachometer Output (CTO)

The PCM uses a crankshaft position (CKP) sensor input to calculate the engine speed. The engine speed information is then output to the transaxle control module (TCM) through the CTO circuit, as a frequency signal. The PCM also broadcasts a redundant engine speed message to the TCM over the CAN communication link. When the broadcasted engine speed disagrees with the hardwired CTO signal, or when the CTO circuit fault condition is detected, the TCM stores an appropriate diagnostic trouble code (DTC).

Coil On Plug (COP)

For information on the COP refer to the description of the COIL-ON-PLUG (COP) .

DC/DC Enable (DCE)

The DCE is an output from the PCM to the DC/DC converter. The PCM enables the DC/DC converter after the PCM receives a contactors closed message and no error messages. The DCE circuit is high (the low side driver is off) when the DC/DC is commanded on. When the DCE low side driver is activated, the DC/DC converter is commanded off. For additional information on DCE, refer to DC/DC CONVERTER .

Exhaust Gas Recirculation (EGR) System

For information on the electric EGR system, refer to ELECTRIC EGR (EEGR) SYSTEM .

Fan Control

The Escape Hybrid uses a relay controlled fan system. The PCM monitors certain parameters (engine coolant temperature, vehicle speed, A/C ON/OFF status, and A/C pressure) to determine engine cooling fan needs. The PCM controls the fan operation through the low fan control (LFC), medium fan control (MFC), and high fan control (HFC) outputs.

For 3-speed fans, although the PCM output circuits are called low, medium, and high fan control (FC), cooling fan speed is controlled by a combination of these outputs. Refer to the following table PCM OUTPUT STATE FOR COOLING FAN SPEEDS .

PCM OUTPUT STATE FOR COOLING FAN SPEEDS

Fuel Injectors

For information on the fuel injectors, refer to the description of the FUEL INJECTOR .

Fuel Pump (FP)

The fuel pump (FP) signal is a duty cycle command sent from the PCM to the fuel pump driver module (FPDM). The FPDM uses the FP command to operate the fuel pump at the speed requested by the PCM or to turn the pump off.

FUEL PUMP DUTY CYCLE OUTPUT FROM PCM

Note. Also refer to FUEL PUMP MONITOR (FPM) and FUEL PUMP DRIVER MODULE (FPDM) .

Fuel Tank Isolation Valve (FTIV)

For information on the FTIV, refer to the description of the FUEL TANK ISOLATION VALVE (FTIV) .

Generator Shut Down (GSDN)

The PCM keeps the generator motor inverter enabled by continuously toggling the GSDN output. Typical output frequency varies between 49 and 75 Hz at 50% duty cycle. The PCM also broadcasts a redundant not shutdown message to the transaxle control module (TCM) over the communication link. When a fault condition is detected, the PCM stops generating this frequency signal and broadcasts a shutdown message to the TCM over the communication link. The TCM then disables the generator motor inverter and sets an appropriate DTC. In the event of GSDN circuit failure, the PCM still broadcasts a not shutdown message but the hard wire signal frequency is out of expected range. The TCM then disables the generator motor inverter and sets the appropriate DTC.

Heater Pump

The heater pump is required to maintain engine coolant flow to the heater core for passenger compartment heating, when the engine is not running. The PCM commands the heater pump ON by energizing the heater pump control relay (HPCR).

The pump is commanded on when the following conditions are met

1. The key is in ON/START position.
2. The engine coolant temperature is above a minimum threshold 0°C (32°F) nominal.
3. The inferred ambient temperature is below a calibrated value 32°C (90°F) nominal.
4. The engine speed is below a calibrated threshold (nominal 4,000 RPM) including engine OFF.
5. The climate control mode switch is in any position other than OFF.

The pump is off when the climate control mode switch is set to OFF.

Scheme 160

Motor Electronics Cooling Pump (MECP)

The motor electronics cooling system is required to maintain an acceptable temperature for the transaxle and the DC/DC converter. The system temperature is monitored by the motor electronics coolant temperature (MECT) sensor, which is an input to the PCM. The PCM commands the MECP using the MECP relay. The MECP is commanded on whenever the traction battery contactors are closed. The coolant in the system flows in a loop from the MECP, to the DC/DC converter, to the top hose port of the motor electronics radiator, out of the motor electronics radiator bottom hose port, into the transaxle, and back into the MECP. The cooling system has a degassing system built into the loop that bleeds air/gases into the coolant reservoir.

Scheme 161

Scheme 162

Motor Shut Down (MSDN)

The PCM keeps the traction motor inverter enabled by continuously toggling the MSDN output. Typical output frequency varies between 49 and 75 Hz at 50% duty cycle. The PCM also broadcasts a redundant not shutdown message to the transaxle control module (TCM) over the communication link. When a fault condition is detected, the PCM stops generating this frequency signal and broadcasts a shutdown message to the TCM over the CAN communication link. The TCM then disables the traction motor inverter and sets an appropriate DTC. In the event of MSDN circuit failure, the PCM still broadcasts a not shutdown message but the hard wire signal frequency is out of expected range. The TCM then disables traction motor inverter and sets the appropriate DTC.

Power Sustain Relay (PSR)

The PSR is wired in parallel with the electronic engine control (EEC) power relay. The PCM and transaxle control module (TCM) use the power sustain relay to keep the modules powered. The PCM and TCM must be powered to complete the normal power down sequence, after key is turned to OFF or ACCS position. For more information on normal power down sequence, refer to NORMAL POWER DOWN SEQUENCE . When the ignition key is cycled from the OFF to ON or the ON/START position, the PCM smart driver grounds the PSR circuit. The PSR coil is energized and it closes the contacts of the PSR supplying the modules with the B+ power. The PSR coil stays energized after the key is turned to the OFF or the ACCS position until normal power down sequence is successfully completed. The PCM monitors the PSR output for an open and short circuit fault condition. The PSR circuit shorted to ground fault condition keeps the modules powered at all times and it may cause an excessive key off load on the low voltage system.

Note. The injectors and ignition coils are powered through a dedicated coil/injector relay so that the engine stops running when the ignition key is turned to the OFF position.

Throttle Actuator Control (TAC) Motor

For information on the TAC motor, refer to TORQUE BASED ELECTRONIC THROTTLE CONTROL (ETC) .

Vapor Management Valve (VMV)

For information on the VMV (EVAP canister purge valve), refer to the description of EVAP CANISTER PURGE VALVE .

Internal Combustion Engine

The 2.3 liter variable compression engine uses the Atkinson cycle for its operation. Sometimes referred to as the five-stroke cycle, it uses a normal intake stroke but at the start of the compression stroke, the intake valve stays open. This allows a backflow stroke of air from the cylinder into the intake manifold which decreases manifold vacuum that requires energy to overcome. Although the intake valve stays open in the compression stroke, it closes early enough to produce sufficient cylinder pressure for combustion. The Atkinson cycle engine is designed to operate in a smaller RPM band than a conventional engine, and it mainly runs at the most efficient RPM range for the maximum fuel economy. The Atkinson cycle is up to 10% more efficient than a conventional four-stroke gasoline engine, but it has reduced low engine RPM torque. The engine is mechanically linked to the electronically controlled continuously variable transaxle (CVT) by the crankshaft and transaxle input shaft, which incorporates a one way clutch (OWC). The OWC prevents the engine from turning in the opposite direction of normal operation under certain conditions. The engine primarily provides torque to the output shafts, charges the high voltage traction battery using the generator motor, and runs the A/C compressor when requested. It also produces heat for the passenger compartment climate control.

Electronically Controlled Continuously Variable Transaxle (CVT)

The primary objective of the electronically controlled CVT is to deliver torque to the drive axles of the vehicle. The CVT transmits input torque from the internal combustion engine, or uses electrical power from the high voltage traction battery. The electrical power is converted into mechanical power by the traction motor and the generator motor. The CVT operates in several different modes, and under certain conditions can transmit power from the traction motor and engine simultaneously or independently. Refer to HYBRID ELECTRIC CONTROL SOFTWARE , operating modes.

The key electronically controlled CVT components are

1. planetary gear set
2. generator motor
3. traction motor
4. one-way clutch
5. transaxle control module (TCM)

Note. Do not attempt to make repairs to any components within the transaxle. Refer to AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for repair procedures.

Planetary Gear Set

The planetary gear set, the generator motor, and the traction motor are internal to the electronically controlled CVT. The planetary gear set mechanically links the internal combustion engine, the electric traction motor, and the electric generator together. It distributes power between the three elements that it connects. The engine is connected to the carrier, the generator motor is connected to the sun gear, and the traction motor to the ring gear of the planetary gear set.

Scheme 163

Generator Motor

The generator motor is a 3-phase permanent magnet AC motor connected to the sun gear of the planetary gear set. The generator power inverter (internal to the transaxle) receives a DC current from the high voltage traction battery. The DC current is inverted to an AC current, which is controlled by the transaxle control module (TCM) and the generator control unit (GCU). Depending on the mode of operation, the generator motor can rotate in the same (clockwise) or reverse (counter clockwise) direction as the internal combustion engine. The TCM also monitors generator position, speed, phase current, power inverter temperature, coil temperature, and voltage. It processes a variety of powertrain control module (PCM) and traction battery control module (TBCM) inputs to determine generator function. The inputs are divided into 2 categories: the hardwired signals and the network messages. The inputs used to determine generator function include the total torque desired, the engine speed desired, the generator mode, the generator shutdown, and the vehicle mode. The generator operates in one of the following generator modes: torque, speed, engine cold start, engine normal start, engine high speed start, and engine enhanced speed control stop. The generator is used as a starter for the internal combustion engine, charges high voltage traction battery, and controls engine speed. The TCM reports the generator error status to the PCM. The PCM initiates an appropriate LOS mode and sets the DTC P1A0D (Hybrid powertrain control module - generator disabled) based on the error status it received. The TCM also sets a DTC which indicates why the generator motor malfunctioned.

Scheme 164

Traction Motor

The traction motor is a 3-phase permanent magnet AC motor connected to the ring gear of the planetary gear set. The traction motor is connected to the drive wheels through a series of gears and rotates whenever the drive wheels rotate. The traction motor power inverter (internal to the transaxle) receives a DC current from the high voltage traction battery. The DC current is inverted to an AC current, which is controlled by the transaxle control module (TCM) and the motor control unit (MCU). The traction motor can deliver positive torque by propelling the vehicle in the forward or reverse direction. It can also provide negative torque by functioning as a generator during the regenerative braking. The TCM receives input from the position sensor as well as the motor coil temperature sensor. The TCM monitors the motor coil temperature and sets a diagnostic trouble code (DTC) if the temperature exceeds a maximum threshold value. The TCM also monitors motor position, speed, phase current, power inverter temperature, and voltage. The TCM processes a variety of the powertrain control module (PCM) and the traction battery control module (TBCM) inputs to determine motor function. The inputs are divided into 2 categories: the hardwired signals and the network messages. The inputs used to determine motor function include the total torque desired, the motor inverter shutdown, and the vehicle mode. The traction motor is used to provide torque to the axle shafts and recharge the high voltage traction battery during the regenerative braking. The TCM reports the motor error status to the PCM. The PCM initiates an appropriate LOS mode and sets the DTC P1A0E (Hybrid powertrain control module - traction motor disabled) based on the error status received. The TCM also sets a DTC which indicates why the traction motor malfunctioned.

Scheme 165

One-Way Clutch

The one-way clutch is internal to the transaxle and its purpose is to prevent the internal combustion engine from turning in the reverse (counterclockwise) direction. The transaxle control module (TCM) reports the one-way clutch error status to the powertrain control module (PCM). The PCM initiates an appropriate LOS mode and sets the P1A11 (Hybrid powertrain control module - one-way clutch disabled) diagnostic trouble code (DTC) based on the error status it received. The TCM also sets a DTC P1A02 which indicates that the one-way clutch malfunctioned.

High Voltage Traction Battery

The high voltage traction battery stores energy for later use by the traction motor and the generator motor. It is connected to both the traction motor and the generator motor by the high voltage cables. The traction motor uses the traction battery power when it propels the vehicle. The generator motor uses the traction battery power when it starts the internal combustion engine. The traction battery also provides energy to the DC/DC converter, which steps down the high voltage to maintain the low voltage system charge. For more information on the charging system, refer to DC/DC CONVERTER . Refer to CHARGING SYSTEM - GENERAL INFORMATION for more information on the high voltage traction battery and diagnostics.

Creep Mode

The hybrid electric system delivers torque to the wheels to mimic the creep normally found on vehicles equipped with an automatic transmission. The powertrain control module (PCM) commands a predetermined amount of torque to be delivered to the output shafts of the electronically controlled continuously variable transaxle (CVT). This torque is delivered from a combination of sources: the internal combustion engine, the traction motor, or the generator motor. The maximum creep speed in forward or reverse direction is about 6 km/h (4 mph). The creep speed may slightly vary if ambient temperature, altitude, relative humidity, engine temperature, or weight of the vehicle change.

Driving Modes

There are 5 fundamental operating modes in the hybrid electric system

1. electric mode
2. positive split mode
3. negative split mode
4. neutral gear mode
5. engine cranking mode

Electric Mode

The hybrid electric system operates in the electric mode when the vehicle is propelled by the electrical power stored in the high voltage traction battery. The torque is supplied to the output shafts by the traction motor, the generator motor, or a combination of both. This is a preferred mode whenever the desired torque is low and the electrical system rather than the engine can produce it more efficiently. The electric mode is also used in reverse because the engine can only deliver torque in a forward direction.

Scheme 166

Positive Split Mode

In this mode the internal combustion engine is running and powering the generator motor which produces the electricity. The power from the engine is split between the path through the generator motor and the path to the output shafts of the vehicle. The electricity produced by the generator motor charges the high voltage traction battery or powers the traction motor. In this mode the traction motor can operate as a motor or as a generator to make up the difference between engine power and desired power at the wheels. This mode is preferred whenever the traction battery needs to be charged.

Scheme 167

Negative Split Mode

In this mode the internal combustion engine is running but the generator motor is reducing the engine speed. This mode is never preferred but occurs when all of the following vehicle conditions are met

1. the engine is running.
2. the vehicle speed is high.
3. the high voltage traction battery is charged.
4. reducing engine throttle is not desired.

Scheme 168

Neutral Gear Mode

The hybrid electric system operates in this mode when the driver selects NEUTRAL. In neutral gear the electronically controlled continuously variable transaxle (CVT) does not deliver any positive or negative torque to the output shafts of the vehicle. The neutral gear actually consists of 2 neutral operating states: active neutral activated above 10 km/h (6 mph), and passive neutral activated below 10 km/h (6 mph). In active neutral, the generator motor is permitted to start and stop the internal combustion engine as needed to maintain the high voltage traction battery charge, and provide A/C. In passive neutral, the engine must remain in the state it was (running or not running) when the mode was entered and is not permitted to change state (start or stop). If the engine is running when entering passive neutral, the speed control of the engine is transferred from the generator motor to the engine itself. The engine controlling its own speed in passive neutral is described as secondary idle. The vehicle cannot be started in passive neutral, but can be started in active neutral.

Engine Cranking Mode

The electronically controlled continuously variable transaxle (CVT) provides the engine cranking function to start or restart the internal combustion engine. When the powertrain control module (PCM) requests the engine cranking mode, the generator motor rapidly accelerates the engine speed up to about 1,000 RPM in about 0.3 seconds. When the engine speed reaches a calibrated speed the PCM commands the delivery of fuel and spark at the appropriate times.

Scheme 169

Limited Operating Strategy (LOS) Modes

For some hybrid electric system malfunctions the powertrain control module (PCM) may initiate one or more of the LOS modes. The objective of the LOS modes is to manage vehicle operation after one or more of the following systems are disabled due to a malfunction: engine, electronically controlled continuously variable transaxle (CVT), traction battery, or regenerative brake system. Some LOS modes limit the vehicle capability to a limp home condition. Other LOS modes fully disable the vehicle. The PCM initiates the appropriate LOS mode depending on the severity of the malfunction that was detected.

When the PCM detects system faults for which the LOS mode is initiated, it stores a corresponding diagnostic trouble code (DTC). The root cause of the malfunction that initiated the LOS mode may be in a different subsystem or component than indicated by the DTC. Therefore, these DTCs should be considered LOS or FMEM only and are always assisted by the other, more detailed, circuit DTCs. The circuit DTCs should always be used to diagnose the problem before LOS or FMEM DTCs. LOS or FMEM DTCs do not mean that the subsystem or component they describe actually failed, but indicate the subsystem or component that is effected by the LOS mode.

1. P1A0C Hybrid Powertrain Control Module - Engine Disabled
2. P1A0D Hybrid Powertrain Control Module - Generator Disabled
3. P1A0E Hybrid Powertrain Control Module - Traction Motor Disabled
4. P1A0F Hybrid Powertrain Control Module - Vehicle Disabled
5. P1A10 Hybrid Powertrain Control Module - Traction Battery Disabled
6. P1A11 Hybrid Powertrain Control Module - One-Way Clutch Disabled
7. P1A13 Hybrid Powertrain Control Module - Regenerative Braking Disabled
8. P1A14 Hybrid Powertrain Control Module - Transmission Disabled

For information on high speed CAN, refer to HIGH SPEED CONTROL AREA NETWORK (CAN) .

For information on multiplexing, refer to MULTIPLEXING .

For information on multiplexing implementation, refer to MULTIPLEXING IMPLEMENTATION .

Normal Power Down Sequence

The powertrain control module (PCM) must conduct a normal power-down sequence. Whenever the key is turned to the OFF or ACC position, modules that are powered up by the RUN circuit immediately shut down. However the PCM, transaxle control module (TCM), and the traction battery control module (TBCM) stay on, until the power-down sequence is complete. The PCM keeps the TCM alive by controlling the power sustain relay (PSR) which provides power to the TCM. The TBCM is powered directly from the low voltage battery which permits wake-up function when the vehicle is off. During the power-down sequence the PCM

1. cuts the power to injectors and ignition coils (engine shut down).
2. requests the TCM to disable high voltage inverters.
3. disables the DC/DC converter.
4. requests the TBCM to open the high voltage contactors.
5. requests the TCM to discharge the high voltage inverter capacitors.
6. opens the power sustain relay.

If the power down sequence does not execute correctly, it is considered an abnormal shut-down, which may result in the PCM, the TCM and the TBCM storing diagnostic trouble codes (DTCs).

Power Up Sequence

The powertrain control module (PCM) must conduct a power-up sequence every time the key is turned from the OFF to the START position. The power-up sequence is carried out only with the electronically controlled continuously variable transaxle (CVT) gear selector in the PARK position. During the power-up sequence the PCM

1. initializes and begins CAN communications with the transaxle control module (TCM) and the traction battery control module (TBCM).
2. checks for TCM error status.
3. requests the TBCM to close the high voltage contactors.
4. enables the DC/DC converter.
5. starts the internal combustion engine.

If the malfunction is detected during the power up sequence, the PCM may initiate LOS mode and store diagnostic trouble codes (DTCs).

Regenerative Braking

The regenerative braking is a software strategy and is controlled by the powertrain control module (PCM), the transaxle control module (TCM), and the traction battery control module (TBCM). Regenerative braking is the ability to capture and store a portion of the energy that would be lost as heat during a braking event. When the driver uses the brakes, the PCM determines how much negative torque (braking force) the traction motor should provide in addition to the friction brakes. Depending on the high voltage traction battery state of charge (SOC), the amount of negative torque provided by traction motor can vary between 0 and 100 percent. The traction motor then becomes a generator, which causes the energy to flow into the high voltage traction battery. The PCM strategy smoothly blends regenerative and friction brake effort to make the dual brake operation transparent to the driver.

Scheme 170

Vehicle System Controller (VSC)

The powertrain control module (PCM), transaxle control module (TCM), and traction battery control module (TBCM) are connected to a high speed controller area network (CAN) to exchange information messages. The VSC is a software function integrated inside the PCM, and is responsible for vehicle system operation, generating and sending commands to initiate appropriate actions such as limited operation strategy (LOS) modes when serious malfunction is detected. The PCM also stores diagnostic trouble codes (DTCs) along with the freeze frame PID related to the LOS action that was initiated. To retrieve DTCs from the PCM an on-demand and continuous memory self-test must be carried out.

DC/DC Converter

The purpose of the DC/DC converter is to function as an alternator in a conventional powertrain. The PCM controls operation of the DC/DC converter. Because the converter does not use any moving parts, the low voltage battery is charged when the vehicle drives with the engine ON or OFF. This is accomplished by converting power from the high voltage traction battery to a regulated output voltage of a nominal 14.5 volts, while supplying a load current of up to 110 amps. The PCM controls the DC/DC enable (DCE) hardwired signal to switch the DC/DC converter on and off. The DC/DC converter provides feedback to the PCM using the hardwired DC/DC fault (DCF) signal. The DCF signal indicates to the PCM when the converter is non-operation or when the malfunction occurred. The DC/DC converter is cooled by the motor electronics cooling system and is located on the passenger side in the engine compartment.

Scheme 171

Hybrid Electric Indicators

The hybrid electric warning indicators alert the driver that a hybrid electric system malfunction is detected. There are 3 indicators dedicated to the hybrid electric system

1. over-temperature indicator
2. caution indicator
3. hazard indicator

Over-Temperature Indicator

The PCM monitors the engine, the motor electronics coolant temperature (MECT), and the electronically controlled continuously variable transaxle (CVT) for an over-temperature condition. If either of the temperatures exceed their threshold value, the fail-safe cooling status changes status to ON, and the PCM broadcasts an over-temperature indicator on CAN message to the instrument cluster. The instrument cluster then illuminates the indicator light. The over-temperature indicator is extinguished when the temperature returns below the threshold value.

Scheme 172

Caution Indicator (Yellow Wrench)

The caution indicator is illuminated whenever a malfunction within the hybrid electric system is detected and a repair is needed. When the malfunction is present, the control module that detected the malfunction stores the DTC and broadcasts a caution on CAN message to the instrument cluster. Upon receiving the CAN message, the instrument cluster turns the indicator on.

Two actions can extinguish the caution indicator light

1. the module requesting the indicator ON is reset.
2. the malfunction is not present anymore and the key is cycled.

If the caution indicator flashes at the once per second rate, it indicates that the vehicle is in the engine running diagnostic mode. Refer to DIAGNOSTIC MODES for engine running diagnostic mode. The caution indicator illuminates for 3 seconds during instrument cluster prove-out when the key is cycled from the OFF to the ON position.

Scheme 173

Hazard Indicator (Red Triangle)

The hazard indicator is illuminated whenever a severe malfunction within the hybrid electric system is detected and continued use of the vehicle is likely to cause damage to the system or to the vehicle. When the malfunction is present, the control module detects, sets the DTC and broadcasts a hazard on CAN message to the instrument cluster. Upon receiving the CAN message, the instrument cluster turns the indicator on.

Two actions can extinguish the hazard indicator light

1. the module requesting the indicator on is reset.
2. the malfunction is not present anymore and the key is cycled.

If the hazard indicator flashes at the once per second rate, it indicates that the vehicle is in the engine cranking diagnostic mode. Refer to DIAGNOSTIC MODES for engine cranking diagnostic mode. The hazard indicator illuminates for 3 seconds during the instrument prove-out when the key is cycled from the OFF to the ON position.

Scheme 174

High Voltage Cables

The high voltage cables connect the high voltage traction battery with the electronically controlled CVT, and the electronically controlled CVT with the DC/DC converter. The harness is orange and contains high voltage positive and high voltage negative wires. Each of the high voltage wires contains a corresponding high voltage interlock (HVIL) circuit.

High Voltage Interlock (HVIL) Circuit

The HVIL circuit, used in conjunction with the front and rear inertia fuel shutoff (IFS) switches, disables the vehicle if a collision occurs or an open circuit fault in the high voltage connection is detected. The HVIL circuit is internal to the high voltage harness, which connects the traction battery, the CVT, and the DC/DC converter. The transaxle control module (TCM) and the traction battery control module (TBCM) monitor the HVIL circuit for a low battery voltage. Whenever that voltage drops below a calibrated threshold, the high voltage traction battery immediately opens its high voltage contactors, the electronically controlled CVT discharges the high voltage capacitors, and the TCM stores the DTC P0A0A. This action is initiated when the vehicle is disabled and cannot be driven.

Scheme 175

Low Voltage Battery Power

The low voltage battery is used as a low voltage energy storage. The battery is charged by the DC/DC converter. For information on the DC/DC converter, refer to DC/DC CONVERTER . The low voltage battery functions are

1. the voltage stabilizer in the system
2. the power source for the power distribution box
3. the power source for all control modules
4. the power source for the traction battery during the jump start procedure

Power Sustain Circuit

For information on the power sustain circuit, refer to POWER SUSTAIN RELAY (PSR) .

Traction Battery Control Module (TBCM)

Refer to HIGH VOLTAGE TRACTION BATTERY for more information on TBCM and diagnostics.

Transaxle Control Module (TCM)

The microprocessor that controls operation of the electronically controlled continuously variable transaxle (CVT) is called the TCM. The TCM receives a variety of CAN messages and hardwired signals from modules connected to the CAN network. Based on information received, the TCM makes a decision on how to control the operation of the generator motor or the traction motor. In case of a malfunction the TCM is able to detect and store the appropriate diagnostic trouble code (DTC). To retrieve DTCs from the TCM, an on-demand and continuous memory self-test must be carried out.

Note. The TCM is a part of the electronically controlled CVT assembly and cannot be repaired as a separate component. Refer to AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for CVT repair procedures.

Transaxle Control Module (TCM) Keep Alive Memory (KAM)

The TCM stores information in KAM (a memory integrated circuit chip) about vehicle operating conditions, and then uses this information to compensate for component variability. KAM remains powered when the key is OFF so that this information is not lost.

For a complete description of the CTO refer to CLEAN TACHOMETER OUTPUT (CTO) .

For a complete description of the GSDN refer to GENERATOR SHUT DOWN (GSDN) .

Immediate Shut Down (ISDN) 1 and 2

The TCM receives the redundant ISDN1 and ISDN2 signals from the high voltage traction battery. Under normal operating conditions the TCM monitors both ISDN circuits for low voltage battery voltage. If at any time during normal operation the TCM detects voltage drop on both ISDN circuits, the electronically controlled continuously variable transaxle (CVT) immediately stops delivering any torque, reduces operating voltage to under 50 volts, and discharges the high voltage capacitors. This action disables the vehicle until the key is cycled OFF and ON. The voltage drop on both ISDN circuits is usually a result of some other concern in the hybrid electric system, and DTCs indicating root cause may be stored in other modules. If the voltage drop is detected on only one of the ISDN circuits, the TCM continues its operation and stores the appropriate DTC. The voltage drop only on one of the ISDN circuits usually indicates an open ISDN circuit.

For a complete description of the MSDN refer to MOTOR SHUT DOWN (MSDN) .

The EI system consists of a crankshaft position (CKP) sensor, coil(s) on plug (COP), and the PCM. The COP integrated EI system uses a separate coil per spark plug, and each coil is mounted directly onto the plug. The COP integrated EI system requires input from the camshaft position (CMP) sensor. Operation of the components are as follows

Scheme 176

1. The CKP sensor is used to indicate crankshaft position and speed by sensing a missing tooth on a pulse wheel mounted to the crankshaft. The CMP sensor is used by the COP integrated EI system to identify the top dead center of compression of cylinder 1 to synchronize the firing of the individual coils.
2. The PCM uses the CKP signal to calculate a spark target and the CMP signal to identify the top dead center of compression of cylinder 1 to synchronize the firing of the individual coils.
3. The COPs receive their signal from the PCM to fire at a calculated spark target. The COP system fires only one spark plug per coil and only on the compression stroke. The PCM acts as an electronic switch to ground in the coil primary circuit. When the switch is closed, battery positive voltage (B+) applied to the coil primary circuit builds a magnetic field around the primary coil. When the switch opens, the power is interrupted and the primary field collapses inducing the high voltage in the secondary coil windings and the spark plug is fired. A kickback voltage spike occurs when the primary field collapses. The PCM uses this voltage spike to generate an ignition diagnostic monitor (IDM) signal. IDM communicates information by pulse width modulation in the PCM.
4. The PCM processes the CKP signal and broadcasts it to the communication network. The PCM also sends it to the TCM as a hardwired clean tachometer output (CTO) signal.

For additional information on the CKP sensor, refer to CRANKSHAFT POSITION (CKP) SENSOR .

The COP integrated EI system uses the CMP sensor information to synchronize the firing of the individual coils. For additional information on the CMP sensor, refer to CAMSHAFT POSITION (CMP) SENSOR .

The COPs are part of the distributorless ignition system. They are the source of the high voltage which is used to generate the spark by the spark plug. The Escape Hybrid uses 4 COPs, one for each cylinder. The COPs are mounted directly onto the spark plugs. The function of the COP is to convert low voltage into a high voltage in excess of 40,000 volts.

The COP consists of primary and secondary windings. The primary winding is energized by the IGN START/RUN circuit. The PCM coil driver circuit is connected to the primary winding as well. The secondary winding is connected to the spark plug. The current flowing through the primary winding generates the magnetic field across both windings. The PCM activates the coil driver circuit by opening it. The instant the circuit opens the magnetic field collapses, inducing current flow in the secondary winding.

The COP has 3 different modes of operation: engine crank, engine running, and CMP failure mode effects management (FMEM).

Scheme 177

Engine Crank/Engine Running

During engine crank the PCM fires 2 spark plugs simultaneously. Of the 2 spark plugs simultaneously fired, one is under compression and the other is on the exhaust stroke. Both plugs fire until the camshaft position is identified by a successful camshaft position sensor signal. Once the camshaft position is identified, only the cylinder under compression is fired.

CMP FMEM

During CMP FMEM the COP ignition works the same as during engine crank. This allows the engine to operate without the PCM knowing if cylinder 1 is under compression or exhaust.

Electronic Returnless Fuel System

The Escape Hybrid uses the electronic returnless fuel system. The system consists of a fuel tank with reservoir, the fuel pump, the fuel filter, the fuel supply line, the fuel rail pressure temperature (FRPT) sensor, the fuel rail, the fuel pump driver module (FPDM), and the fuel injectors. Operation of the system is as follows

1. The fuel delivery system is enabled during crank or running mode once the PCM receives a crankshaft position (CKP) sensor signal.
2. The fuel pump logic is defined in the fuel system control strategy and is executed by the PCM.
3. The PCM commands a duty cycle to the FPDM.
4. The FPDM modulates the voltage to the fuel pump (FP) required to achieve the proper fuel pressure. Voltage for the fuel pump is supplied by the FPDM. For additional information on FPDM operation, refer to «FUEL PUMP (FP)»(ref-235203-S14438085482006061500000) and «FUEL PUMP MONITOR (FPM)»(ref-235203-S14867193312006061500000) .
5. The FRPT sensor provides the PCM with the current fuel rail pressure and temperature. The PCM uses this information to vary the duty cycle output to the FPDM to compensate for varying loads.
6. The fuel injector is a solenoid operated valve that meters the fuel flow to each combustion cylinder. The fuel injector is opened and closed a constant number of times per crankshaft revolution. The amount of fuel is controlled by the length of time the fuel injector is held open. The injector is normally closed and is operated by VPWR from the power relay. The ground signal is controlled by the PCM.
7. There are 3 filtering or screening devices in the fuel delivery system. The intake sock is a fine, nylon mesh screen mounted on the intake side of the fuel pump. There is a fuel filter screen located at the fuel rail side of the fuel injector. The fuel filter assembly is located between the fuel pump and the fuel rail.
8. The fuel pump (FP) module is a device that contains the fuel pump and the fuel sender assembly. The fuel pump is located inside the reservoir and supplies fuel through the fuel pump module manifold to the engine and the fuel pump module jet pump.
9. The front inertia fuel shut-off (IFS) switch is used to de-energize the fuel delivery secondary circuit the event of a collision. The IFS switch is a safety device that should only be reset after a thorough inspection of the vehicle following a collision.

Scheme 178

Fuel Pump (FP) Module

The FP module is a device that contains the fuel pump and sender assembly. The fuel pump is located inside the FP module and supplies fuel through the FP module manifold to the engine and FP module jet pump. The jet pump continuously refills the reservoir with fuel, and a check valve located in the manifold outlet maintains system pressure when the fuel pump is not energized. A flapper valve located in the bottom of the reservoir allows fuel to enter the reservoir and prime the fuel pump during the initial fill.

Scheme 179

Fuel Filters

The system contains 3 filtering or screening devices.

1. The fuel intake sock or screen is a fine nylon mesh sock mounted on the intake side of the fuel pump. It is part of the assembly and cannot be repaired separately.
2. The filter/screen at the fuel rail port of the injectors is part of the fuel injector assembly and cannot be repaired separately.
3. The fuel filter assembly is located between the fuel pump (tank) and the fuel rail. This filter may be repaired or replaced.

Fuel Injector

The fuel injector is a solenoid operated valve that meters fuel flow to the engine. The fuel injector is opened and closed a constant number of times per crankshaft revolution. The amount of fuel is controlled by the length of time the fuel injector is held open.

The fuel injector is normally closed, and is operated by VPWR from the electronic engine control (EEC) power relay. The ground signal is controlled by the PCM.

The injector is the deposit resistant injection (DRI) type and does not have to be cleaned. However, it can be flow checked and, if found outside of specification, the fuel injector should be replaced.

Scheme 180

Electric EGR (EEGR) System

1. The EEGR valve is activated by an electric stepper motor and does not use vacuum to control the physical movement of the valve.
2. No DPFE sensor is used.
3. No orifice tube/assembly is used.
4. A manifold absolute pressure (MAP) sensor.
5. Engine coolant is routed through the EEGR assembly extending the durability of the electric motor.

Hardware

The EEGR valve is a water cooled motor/valve assembly. The motor is commanded to move in 52 discrete steps as it acts directly on the EEGR valve. The position of the valve determines the rate of EGR. The built-in spring works to close the valve against the motor opening force.

Scheme 181

Enhanced Evaporative Emission (EVAP) System

The enhanced EVAP system consists of a fuel tank, fuel tank isolation valve (FTIV), fuel filler cap, fuel vapor control valve, fuel vapor vent valve, EVAP canister, fuel tank pressure (FTP) sensor, vapor management valve (VMV), intake manifold hose assembly, canister vent (CV) solenoid, powertrain control module (PCM) and the connecting wires and fuel vapor hoses.

1. The enhanced EVAP system uses inputs from the cylinder head temperature (CHT) sensor, the intake air temperature (IAT) sensor, the mass air flow (MAF) sensor, the vehicle speed and the fuel tank pressure (FTP) sensor to provide information about engine operating conditions to the PCM. The fuel level input (FLI) and FTP sensor signals to the PCM are used by the PCM to determine activation of the EVAP leak check monitor based on the presence of vapor generation or fuel sloshing.
2. The PCM determines the desired amount of purge vapor flow to the intake manifold for a given engine condition. The PCM can then output the required signal to the EVAP canister purge valve. The PCM uses the enhanced EVAP system inputs to evacuate the system using the EVAP canister purge valve, seals the enhanced EVAP system from the atmosphere using the CV solenoid, and uses the FTP sensor to measure the total vacuum lost for a period of time.
3. The CV solenoid seals the enhanced EVAP system from the atmosphere during the EVAP leak check monitor.
4. The PCM outputs a variable duty cycle signal (between 0% and 100%) and a variable current (between 0 mA and 1000 mA) to the solenoid on the EVAP canister purge valve.
5. The FTP sensor monitors the fuel tank pressure during engine operation and continuously transmits an input signal to the PCM. During the EVAP monitor testing, the FTP sensor monitors the fuel tank pressure or vacuum bleed-up.
6. The fuel tank mounted fuel vapor vent valve assembly and the fuel tank mounted fuel vapor control valve are used in the enhanced EVAP system to control the flow of fuel vapor entering the engine. These valves also prevent fuel tank overfilling during refueling operation, and prevent liquid fuel from entering the EVAP canister and the EVAP canister purge valve under any vehicle altitude, handling, or rollover condition.
7. The FTIV isolates the fuel tank from the rest of the EVAP system when the vapor flow is required only from the EVAP canister, and not from the fuel tank.
8. The enhanced EVAP system, including all the fuel vapor hoses, can be checked when a leak is detected by the PCM. Refer to «EVAPORATIVE EMISSIONS - HYBRID»(ref-232274) for information on leak detection tools and procedures.

Scheme 182

Canister Vent (CV) Solenoid

During the EVAP leak check monitor, the CV solenoid seals the EVAP canister from atmospheric pressure. This allows the EVAP canister purge valve to obtain the target vacuum in the fuel tank during the EVAP leak check monitor.

Scheme 183

EVAP Canister Purge Valve

The EVAP canister purge valve, also known as vapor management valve (VMV), is part of the enhanced EVAP system that is controlled by the PCM. This valve controls the flow of vapors (purging) from the EVAP canister to the intake manifold during various engine operating modes. The EVAP canister purge valve is a normally closed valve. The electronic EVAP canister purge valve controls the flow of vapors electronically by way of a solenoid, thereby eliminating the need for an electronic vacuum regulator and vacuum diaphragm. The PCM outputs a variable duty cycle signal (between 0% and 100%) and a variable current (between 0 mA and 1000 mA) to the solenoid on the EVAP canister purge valve.

Scheme 184

The FTIV is a PCM controlled solenoid which isolates the fuel tank from the rest of the EVAP system. The FTIV is a normally open valve allowing the flow of vapors from the fuel tank to the electronic EVAP canister purge valve and the EVAP canister. Whenever it is desired to isolate the fuel tank from the rest of the EVAP system, the PCM provides a variable duty cycle signal (between 0% and 100%) to the solenoid which controls the FTIV operation.

Scheme 185

The FTP sensor is used to measure the fuel tank pressure during the EVAP leak check monitor.

Scheme 186

Intake Manifold Runner Control (IMRC) Vacuum Actuated System

The IMRC subsystem is used to provide increased intake airflow to improve torque, emissions and performance. The IMRC vacuum actuated system consists of a manifold mounted vacuum actuator and a PCM controlled electric solenoid. The linkage from the actuator attaches to the manifold butterfly plate lever. The IMRC actuator and manifold are composite/plastic with a single intake air passage for each cylinder. The passage has a butterfly valve plate that blocks 60% of the opening when actuated, leaving the top of the passage open to generate turbulence. The housing uses a return spring to hold the butterfly valve plates open. The vacuum actuator houses an internal monitor circuit to provide feedback to the PCM indicating the butterfly valve plate position.

On the initial engine start up the IMRC butterfly valve plates may remain open until the desired engine load and speed is reached. Once the desired engine load and speed are met, the IMRC vacuum actuator is energized which allows the manifold vacuum to close the IMRC butterfly valve plates. The IMRC butterfly valve plates open when the engine shuts off during a normal operation and close when the engine restarts.

Scheme 187

1. The PCM monitors the throttle position (TP) sensor, cylinder head temperature (CHT) sensor, and crankshaft position (CKP) sensor signals to determine activation of the IMRC system. There must be a positive change in voltage from the TP sensor along with the increase in engine load and engine RPM at the proper engine temperature to open the valve plates.
2. The PCM uses the information from the input signals to control the IMRC electric solenoid based upon changes in the throttle position, the engine temperature, the engine load, and the RPM.
3. The PCM energizes the solenoid with the key on engine running. Vacuum is then applied to the actuator to pull the butterfly plates closed.

Throttle Body

Refer to TORQUE BASED ELECTRONIC THROTTLE CONTROL (ETC) for information on the throttle body.

Exhaust System

The purpose of the exhaust system is to convey engine emissions from the exhaust manifold to the atmosphere. Engine exhaust emissions are directed from the engine exhaust manifold to the catalytic converter through the front exhaust pipe. An HO2S is mounted on the front exhaust pipe before the catalyst. The catalytic converter reduces the concentration of carbon monoxide (CO), unburned hydrocarbons (HCs), and oxides of nitrogen (NO x) in the exhaust emissions to an acceptable level. The reduced exhaust emissions are directed from the catalytic converter through another HO2S mounted in the rear exhaust pipe and then into the muffler. Finally, the exhaust emissions are directed to the atmosphere through an exhaust tailpipe.

The Escape Hybrid is a PZEV and it has a total of 3 HO2S in the exhaust stream. First near the exhaust manifold (stream 1), one in the middle (not used by the PCM) and the last (stream 2) is mounted after the light off catalyst.

Scheme 188

Exhaust Manifold/Runners

The exhaust manifold runners collect exhaust gases from the engine cylinders.

Heated Oxygen Sensors (HO2S)

The HO2S provide the powertrain control module (PCM) with voltage and frequency information related to the oxygen content of the exhaust gas. Refer to HEATED OXYGEN SENSOR (HO2S) for a description of how the HO2S operates.

Catalytic Converter

A catalyst is a material that remains unchanged when it initiates and increases the speed of a chemical reaction. A catalyst also enables a chemical reaction to occur at a lower temperature. The concentration of exhaust gas products released to the atmosphere must be controlled. The catalytic converter assists in this task. It contains a catalyst in the form of a specially treated ceramic honeycomb structure saturated with catalytically active precious metals. As the exhaust gases come in contact with the catalyst they are changed into mostly harmless products. The catalyst initiates and speeds up heat producing chemical reactions of the exhaust gas components so they are used up as much as possible.

Light Off Catalyst

As the catalyst heats up, converter efficiency rises rapidly. The point at which conversion efficiency exceeds 50% is called catalyst light off. For most catalysts this point occurs at 246°C to 301°C(475°F to 575°F). Because the light off catalyst is located close to the exhaust manifold it lights off faster and reduces emissions quicker than the catalyst located under the body. Once the catalyst lights off, it quickly reaches the maximum conversion efficiency for that catalyst.

Underbody Catalyst

The underbody catalyst is located after the light off catalyst. The underbody catalyst is in-line with the light off catalyst. For an exact configuration of the catalyst and exhaust system refer to EXHAUST SYSTEM .

Exhaust Pipes

Exhaust pipes are usually treated with an anti-corrosive coating agent during manufacturing to increase the life of the product. The pipes serve as guides for the flow of exhaust gases from the engine exhaust manifold through the catalytic converter and the muffler.

Muffler

Mufflers are usually treated with an anti-corrosive coating agent during manufacturing to increase the life of the product. The muffler reduces the level of noise produced by the engine, and it also reduces the noise produced by exhaust gases as they travel from the catalytic converter to the atmosphere.

Electronic Throttle Body (ETB)

The Gen II electronic throttle body has the following characteristics

1. The DC motor is driven by the PCM (requires 2 wires). The gear ratio from the motor to the throttle plate shaft is 17:1.
2. Two springs are used: one is used to close the throttle (main spring) and the other is in a plunger assembly that results in a default angle with no power applied. This is for limp home reasons (the force of the plunger spring is 2 times stronger than the main spring). The default angle is usually set to result in a top vehicle speed of 48 km/h (30 mph). Typically this throttle angle is 7 to 8 degrees from the hard-stop angle.
3. The closed throttle plate hard stop is used to prevent the throttle from binding in the bore (~0.75 degree). This hard stop setting is non-adjustable and is set to result in less airflow than the minimum engine airflow required at idle.
4. Unlike cable type throttle bodies, the intent for the ETB is to not have a hole in the throttle plate or to use plate sealant. The hole is not required in the ETB because the required idle airflow is provided by the plate angle in the throttle body assembly. This plate angle controls idle and idle quality and eliminates the need for an IAC valve.
5. The system has 2 throttle position sensors. Redundant throttle position signals are required for monitor reasons. The TP1 has a negative slope (increasing angle, decreasing voltage) and the TP2 has a positive slope (increasing angle, increasing voltage). During normal operation the negative sloped TP sensor (TP1) is used by the control strategy as the indication of the throttle position. The TP sensor assembly requires 4 wires

1. 5 volt reference voltage (ETCREF)
2. Signal return (ETCRTN)
3. TP1 voltage with negative voltage slope 5 volts to 0 volts
4. TP2 voltage with positive voltage slope 0 volts to 5 volts

Accelerator Pedal Position (APP) Sensors

The ETC strategy uses pedal position as an input to determine the driver demand.

Scheme 189

1. There are 3 pedal position sensors required for system monitoring. The APP1 has a negative slope (increasing angle, decreasing voltage) and APP2 and APP3 both have a positive slope (increasing angle, increasing voltage). During normal operation APP1 is used as the indication by the strategy.
2. There are 2 VREF signals (ETCEREF1 and ETCREF2), 2 signal returns (ETCRTN1 and ETCRTN2), and 3 signals (APPS1, APPS2, and APPS3) between the PCM and APP assembly. 5 volt reference voltage circuits (2) Signal return (ground) circuits (2) APP1 voltage with negative voltage slope 5 volts to 0 volts APP2 voltage with positive voltage slope 0 volts to 5 volts APP3 voltage with positive voltage slope 0 volts to 5 volts
3. The pedal position signal is converted to pedal travel degrees (rotary angle) by the PCM. The software then converts these degrees to counts, which is the input to the torque based strategy.
4. The 3 pedal position signals provide a correct input to the PCM should any one signal have a fault. The PCM knows if a signal is wrong by calculating where it should be, inferred from the other signals. A value is substituted for a faulty signal if 2 out of the 3 signals are bad.

Electronic Throttle Control (ETC) System Strategy

The ETC strategy was developed mainly to improve fuel economy. This is possible by not coupling the throttle angle to the drivers pedal position and by uncoupling the throttle angle (produce engine torque) from pedal position (driver demand). This allows the powertrain control strategy to optimize fuel control while delivering the requested wheel torque.

The ETC monitor system is distributed across 2 processors within the PCM: the main powertrain central processing unit (CPU) and a monitoring processor called an enhanced quizzer (E-Quizzer) processor. The primary monitoring function is carried out by the independent plausibility check (IPC) software, which resides on the main processor. It is responsible for determining the driver demanded torque and comparing it to an estimate of the actual torque delivered. If the generated torque exceeds driver demand by a specified amount, the IPC takes appropriate action.

Since the IPC and the main controller share the same processor, they are subject to a number of potential, common failure modes. Therefore, the E-Quizzer processor was added to redundantly monitor selected PCM inputs and to act as an intelligent watchdog and monitor the performance to the IPC and the main processor. If the E-Quizzer determines that the IPC function is impaired in any way, it takes appropriate failure mode and effects management (FMEM) actions.

Scheme 190

ETC SYSTEM FAILURE MODE AND EFFECTS MANAGEMENT CHART

Accelerator and Throttle Position Sensor Inputs

ACCELERATOR PEDAL POSITION SENSOR CHECK

THROTTLE POSITION SENSOR CHECK

Throttle Plate Position Controller (TPPC) Outputs

The purpose of the TPPC is to control the throttle position to the desired throttle angle. It is a separate chip embedded in the PCM. The desired angle is communicated from the main CPU over a 312.5 Hz duty cycle signal. The TPPC interprets the duty cycle signal as follows

1. Less than 5% - Out of range, limp home default position.
2. Greater than or equal to 5% but less than 6% - Commanded default position, closed.
3. Greater than or equal to 6% but less than 7% - Commanded default position. off.
4. Greater than or equal to 7% but less than 10% - Closed against hard-stop. Used to learn zero throttle angle position (hard-stop) after key-up.
5. Greater than or equal to 10% but less than or equal to 92% - Normal operation, between 0 degrees (hard-stop) and 82 degrees, 10% duty cycle = 0 degrees throttle angle, 92% duty cycle = 82 degrees throttle angle.
6. Greater than 92% but less than or equal to 96% - Wide Open Throttle, 82 to 86 degrees throttle angle.
7. Greater than 96% but less than or equal to 100% - Out of Range, limp home default position.

The desired angle is relative to the hard-stop angle. The hard-stop angle is learned during each key-up process before the main CPU requests the throttle plate to be closed against the hard-stop. The output of the TPPC is a voltage request to the H-driver (also in PCM). The H-driver is capable of providing a positive or negative voltage to the electronic throttle body motor.

THROTTLE PLATE CONTROLLER CHECK OPERATION

ELECTRONIC THROTTLE MONITOR OPERATION