Mechanics

EGR AND EVAP MONITORS

2007 Ford Fusion • 61,000 miles

I cannot get my EGR and Evap monitors to register, despite driving my drive cycle listed in my owners manual at least 6 times from an 8 hour rest each time. I scanned my vehicle and sent a start command to test for vacuum leaks but that did nothing to fix.

I initially used my scanner to clear a trouble code for low coolant temperature ( either the thermostat was sticking open at times or the manufacturer put the wrong temperature thermostat in for the sensor ) After that I needed to pass emissions for plate renewal. It failed due to not ready for test. I drove it the drive cycle as stated in owners manual from a cold start each time, a total of 6 cycles. I cannot get 2 monitors to be ready and I can only have 1 not ready to pass. I sent command to start vacuum test ( via scanner ) but that did not change anything. My EGR and Evap monitors both show inc ( not ready). What can I do? I already drove it over 150 miles through those 6 cycles.

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Larry Pinczkowski
February 10, 2012.




Here is some info that may help you.

EVAPORATIVE EMISSION (EVAP) LEAK CHECK MONITOR

The EVAP leak check monitor is an on-board strategy designed to detect a leak from a hole (opening) equal to or greater than 0.508 mm (0.020 inch) in the enhanced EVAP system. The correct 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 either allow a natural vacuum to occur in the fuel tank or apply engine 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 engine coolant temperature (ECT) sensor or cylinder head temperature (CHT) sensor, intake air temperature (IAT) sensor, mass air flow (MAF) sensor, vehicle speed, fuel level input (FLI) and fuel tank pressure (FTP) sensor are required to enable the EVAP leak check monitor.

During the EVAP leak check monitor repair verification drive cycle, clearing the continuous diagnostic trouble codes (DTCs) and resetting the emission monitors information in the powertrain control module (PCM) 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 continuous DTCs and resetting the emission monitors information in the PCM. The EVAP leak check monitor does not run if a MAF sensor concern is present. The EVAP leak check monitor does not initiate until the heated oxygen sensor (HO2S) monitor is complete.

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. Therefore, the test is complete for the day.

Some vehicle applications have an engine off natural vacuum (EONV) check as part of the EVAP leak check monitor.

Engine On EVAP Leak Check Monitor

Evaporative Emission (EVAP) Leak Check Monitor

The engine on EVAP leak check monitor is executed by the individual components of the enhanced EVAP system as follows: The EVAP canister purge valve, also known as 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.
The canister vent (CV) solenoid is used to seal the EVAP system from the atmosphere. It is closed by the PCM (100% duty cycle) to allow the EVAP canister purge valve to obtain the target vacuum on the fuel tank.
The FTP sensor is used by the engine on EVAP leak check monitor to determine if the target vacuum necessary to carry out the leak check on the fuel tank is reached. Some vehicle applications with the engine on EVAP leak check monitor use a remote in-line FTP sensor. Once the target vacuum on the fuel tank is achieved, the change in fuel tank vacuum over a calibrated period of time determines if a leak exists.
If the initial target vacuum cannot be reached, DTC P0455 (gross leak detected) is set. The engine on EVAP leak check monitor aborts and does not continue with the leak check portion of the test.

For some vehicle applications, 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 cannot be reached and the purge flow is too small, DTC P1443 (no purge flow condition) is set.

If the initial target vacuum is exceeded, a system flow concern exists and DTC P1450 (unable to bleed-up fuel tank vacuum) is set. The engine on 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 1.016 mm (0.040 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. The test can be repeated up to 3 times.

If the bleed-up threshold is still being exceeded after 3 tests, a vapor generation test 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 EVAP canister purge valve and opening the CV solenoid. Once the FTP sensor observes the fuel tank is at atmospheric pressure, the CV solenoid closes and seals the enhanced EVAP system.

The fuel tank pressure build-up, over 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 engine on EVAP leak check monitor attempts to repeat the test again.

If the fuel tank pressure build-up does not exceed the threshold, the leak test results are valid and DTC P0442 is set.

If the 1.016 mm (0.40 inch) test passes, the test time is extended to allow the 0.508 mm (0.020 inch) test to run.

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, the vapor generation test is run. If the vapor generation test 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.

The MIL is activated for DTCs P0442, P0455, P0456, P0457, P1443, and P1450 (or P0446) after 2 occurrences of the same concern. 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, P0453, and P1451 are tested as part of the CCM.

Engine Off Natural Vacuum (EONV) EVAP Leak Check Monitor

EONV EVAP Leak Check Monitor

The EONV EVAP leak check monitor is executed during key off, after the engine on EVAP leak check monitor is completed. The EONV EVAP leak check monitor determines a leak is present when the naturally occurring change in fuel tank pressure or vacuum does not exceed a calibrated limit during a calibrated amount of time. A separate, low power consuming, microprocessor in the PCM manages the EONV leak check. The engine off EVAP leak check monitor is executed by the individual components of the enhanced EVAP system as follows: The EVAP canister purge valve, also known as the vapor management valve (VMV), is normally closed at key off.
The normally open canister vent (CV) remains open for a calibrated amount of time to allow the fuel tank pressure to stabilize with the atmosphere. During this time period the FTP sensor is monitored for an increase in pressure. If pressure remains below a calibrated limit the CV is closed by the PCM (100% duty cycle) and seals the EVAP system from the atmosphere.
The FTP sensor is used by the EONV EVAP leak check monitor to determine if the target pressure or vacuum necessary to complete the EONV EVAP leak check monitor on the fuel tank is reached. Some vehicle applications with the EONV EVAP leak check monitor use a remote in-line FTP sensor. If the target pressure or vacuum on the fuel tank is achieved within the calibrated amount of time, the test is complete.
The EONV EVAP leak check monitor uses the naturally occurring change in fuel tank pressure as a means to detect a leak in the EVAP system. At key off, a target pressure and vacuum is determined by the PCM. These target values are based on the fuel level and the ambient temperature at key off. As the fuel tank temperature increases, the pressure in the tank increases and as the temperature decreases a vacuum develops. If a leak is present in the EVAP system the fuel tank pressure or vacuum does not exceed the target value during the testing time period. The EONV EVAP leak check monitor begins at key off.

After key off the normally open canister vent (CV) remains open for a calibrated amount of time to allow the fuel tank pressure to stabilize with the atmosphere. During this time period the FTP sensor is monitored for an increase in pressure. If pressure remains below a calibrated limit the CV is closed by the PCM (100% duty cycle) and seals the EVAP system from the atmosphere.

If the pressure on the fuel tank decreases after the EVAP system is sealed, the EONV EVAP leak check monitor begins to monitor the fuel tank pressure. When the target vacuum is exceeded within the calibrated amount of time the test completes and the fuel tank pressure and time since key off information is stored. If the target vacuum is not reached in the calibrated amount of time, a leak is suspected and the fuel tank pressure and time since key off information is stored.

If the pressure on the fuel tank increases after the EVAP system is sealed, but does not exceed the target pressure within a calibrated amount of time the CV is opened to allow the fuel tank pressure to again stabilize with the atmosphere. After a calibrated amount of time the CV is closed by the PCM and seals the EVAP system. When the fuel tank pressure exceeds either the target pressure or vacuum within the calibrated amount of time the test completes and the fuel tank pressure and time since key off information is stored. If the target pressure or vacuum is not reached in the calibrated amount of time, a leak is suspected and the fuel tank pressure and time since key off information is stored.

When a leak is suspected, the PCM uses the stored fuel tank pressure and time since key off information from an average run of 4 tests to suspect a leak. Some vehicles use an alternative method of a single run of 5 tests to determine the presence of a leak. If a leak is still suspected after 2 consecutive runs of 4 tests, (8 total tests) or 1 run of 5 tests, DTC P0456 is set and the MIL is illuminated.

The EONV EVAP leak check monitor is controlled by a separate low power consuming microprocessor inside the PCM. The fuel level indicator, fuel tank pressure, and battery voltage are inputs to the microprocessor. The microprocessor outputs are the CV solenoid and the stored test information. If the separate microprocessor is unable to control the CV solenoid or communicate with other processors DTC P260F is set.
The MIL is activated for DTCs P0456 and P260F. The MIL can also be activated for any enhanced EVAP system component DTCs in the same manner. The enhanced EVAP system component DTCs P0443, P0446, P0452, P0453, and P1451 are tested as part of the CCM.

EXHAUST GAS RECIRCULATION (EGR) SYSTEM MONITOR - DIFFERENTIAL PRESSURE FEEDBACK EGR AND EGR SYSTEM Module (ESM)

EGR System Monitor - Different Pressure Feedback EGR

The EGR system monitor is an on-board strategy designed to test the integrity and flow characteristics of the EGR system. The monitor is activated during EGR system operation and after certain base engine conditions are satisfied. Input from the engine coolant temperature (ECT) or cylinder head temperature (CHT), intake air temperature (IAT), throttle position (TP), and crankshaft position (CKP) sensors is required to activate the 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 an on-demand self-test.

The differential pressure feedback EGR sensor and circuit are continuously tested for opens and shorts. The monitor checks for the differential pressure feedback EGR circuit voltage to exceed the maximum or minimum allowable limits.

The diagnostic trouble codes (DTCs) associated with this test are P0405 and P0406.

The EGR vacuum regulator solenoid is continuously tested for opens and shorts. The monitor looks for an EVR circuit voltage that is inconsistent with the EVR circuit commanded output state.

The DTC associated with this test is P0403.

The test for a stuck open EGR valve or EGR flow at idle is continuously carried out at idle (TP sensor indicating closed throttle). The monitor compares the differential pressure feedback EGR circuit voltage at idle to the differential pressure feedback EGR circuit voltage stored during key on engine off (KOEO) to determine if EGR flow is present at idle.

The DTC associated with this test is P0402.

The differential pressure feedback EGR sensor hoses are tested once per drive cycle for disconnect and plugging. The test is carried out with the EGR valve closed and during a period of acceleration. The powertrain control module (PCM) momentarily commands the EGR valve closed. The monitor looks for the differential pressure feedback EGR sensor voltage to be inconsistent for a no flow voltage. A voltage increase or decrease during acceleration while the EGR valve is closed may indicate a concern with a signal hose during this test.

The DTCs associated with this test are P1405 and P1406 (differential pressure feedback EGR systems only).

The EGR flow rate test is carried out during a steady state when the engine speed and load are moderate and the EGR vacuum regulator duty cycle is high. The monitor compares the actual differential pressure feedback EGR circuit voltage to a desired EGR flow voltage for that state to determine if the EGR flow rate is acceptable or insufficient. This is a system test and may trigger a DTC for any concern causing the EGR system to fail.

The DTC associated with this test is P0401. DTC P1408 is similar to P0401 but is carried out during key on engine running (KOER) self-test conditions.

The MIL is activated after one of the above tests fails on 2 consecutive drive cycles.

Wrenchtech
Feb 10, 2012.


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