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DTC P0442 EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECTED (SMALL LEAK)

DTC P0442 EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECTED (SMALL LEAK)

OUTLINE OF DIAGNOSIS

Perform the diagnosis of leakage of fuels system and valve functions.


(1)

Fuel gauge

(10)

Canister

(19)

Fuel tank

(2)

Combination meter

(11)

Engine control module (ECM)

(20)

Vent valve

(3)

Fuel injector

(12)

Pressure control solenoid valve

(21)

Shut-off valve

(4)

Pressure regulator

(13)

Fuel tank pressure sensor

(22)

Drain filter

(5)

Throttle body

(14)

Fuel temperature sensor

(23)

Fuel sub level sensor

(6)

Intake manifold

(15)

Fuel level sensor

(24)

Fuel tank sensor control valve

(7)

Fuel filter

(16)

Fuel pump

(8)

Purge control solenoid valve

(17)

Jet pump

(A)

Fuel line

(9)

Drain valve

(18)

Fuel cut valve

(B)

Fuel evaporation line



In this system diagnosis, checking for leakage and valve function is conducted by changing the fuel tank pressure, and monitoring the pressure change using the fuel tank pressure sensor. 0.04 inch diagnosis is performed in the order of mode Z, mode A, mode B, mode C and mode D, and 0.02 inch diagnosis is performed in the order of mode A, mode B, mode C, mode D and mode E.

0.04-inch Diagnosis


Mode Mode Description Diagnosis Period
Mode Z

(CPC abnormal open diagnosis)

Diagnosis starts when there is a change in fuel tank pressure amount. Purge control solenoid valve open trouble diagnosis begins.

3 — 16 seconds

Mode A

(Estimated evaporation amount)

Calculate the tank pressure change amount (P1).

10 seconds

Mode B

(Sealed negative pressure/large leakage judgment)

Introduce the intake manifold pressure to the fuel tank and reduce the tank pressure to the desired value.

If the tank pressure cannot be reduced, it is diagnosed as large leak.

5 — 25 seconds

Mode C

(Pressure increase check/advanced OK judgment)

Wait until the tank pressure becomes the desired value (detection starting pressure of P2). If the tank pressure does not become the value, make advanced OK judgment.

1 — 15 seconds

Mode D

(Negative pressure variation measurement/evaporation leakage diagnosis)

Calculate the tank pressure variation (P2), and obtain the diagnostic value using P1 of Mode 1. Perform the evaporation leakage diagnosis using the diagnostic value.

10 seconds



Mode Table for Evaporative Emission Control System Diagnosis

Mode Behavior of tank internal pressure under normal conditions Diagnostic item DTC
Mode Z

Nearly same as atmospheric pressure (equivalent pressure of 0 kPa (0 mmHg, 0 inHg))

CPC is judged to be stuck open.

P0457

Mode A

Pressure is in proportion to amount of evaporative emission.

Mode B

Negative pressure is formed due to intake manifold negative pressure

Large leakage

P0457

Mode C

Target pressure is reached.

None

Mode D

Pressure change is small.

EVAP system is judged to have large leak [1.0 mm (0.04 in)].

P0442



0.02-inch Diagnosis


Mode Mode Description Diagnosis Period
Mode A

(0 point correction)

Wait until the tank pressure returns to 0 point (near 0 mm Hg) when tank pressure is high.

0 s — 12 s

Mode B

(Negative pressure Introduction)

Introduce the intake manifold pressure into fuel tank to reduce the tank pressure to the desired value.

0 s — 27 s

Mode C

(Holding negative pressure)

Wait until the tank pressure becomes the desired value (detection starting pressure of P2).

0 s — 20 s

Mode D

(Calculation of negative pressure variation)

Calculate the time that takes the tank pressure to return to detection completing pressure of P2. When the tank pressure does not return to the detection completing pressure of P2, make advanced OK judgment.

0 s — 200 s

Mode E

(Calculation of yielded evaporation amount)

Calculate the yielded evaporation amount (P1).

0 s — 280 s



COMPONENT DESCRIPTION

Pressure Control Solenoid Valve

PCV controls the fuel tank pressure to be equal to the atmospheric air pressure.

Normally, the solenoid is set to OFF. And the valve opens and closes mechanically in accordance with the pressure difference between tank and atmospheric air, or tank and canister.

The valve is forcibly opened by setting the solenoid to ON at the time of diagnosis.


(1)

Solenoid

(a)

Atmospheric pressure

(2)

Diaphragm

(b)

Fuel tank

(3)

Valve

(c)

Canister

(4)

Spring



Valve Operation and Air Flow

In the figure below, divided by the diaphragm, the part above X is charged with atmospheric air pressure, and the part below X is charged with tank pressure. Also, the part above Y is charged with tank pressure, and the part below Y is charged with canister pressure.

If the atmospheric air pressure port is A, tank pressure port is B, and canister pressure port is C, the air flows according to pressure difference from each port as shown in the table below.


(a)

Atmospheric pressure

(b)

Fuel tank

(c)

Canister



Condition of pressure Flow
A < B (solenoid OFF)

B → C

B < C (solenoid OFF)

C → B

Solenoid ON

B ←→ C



When A < B (Solenoid OFF)


(a)

Atmospheric pressure

(b)

Fuel tank

(c)

Canister



When B < C (Solenoid OFF)


(1)

Valve

(a)

Atmospheric pressure

(b)

Fuel tank

(c)

Canister



When Solenoid is ON


(a)

Atmospheric pressure

(b)

Fuel tank

(c)

Canister



CCV

CCV controls the ambient air to be introduced to the canister.


ENABLE CONDITION

0.04-inch Diagnosis

Secondary Parameters Enable Conditions
Battery voltage

≥ 10.9 V

Barometric pressure

≥ 75.1 kPa (563 mmHg, 22.17 inHg)

Cumulative time of canister purge

120 seconds or more

After engine starting

856 seconds or more

Learning value of evaporation gas density

≤ 0.08

Engine speed

1050 ←→ 6000 rpm

Fuel tank pressure

≥ −4.00 kPa (−30 mmHg, −1.18 inHg)

Intake manifold vacuum (relative pressure)

< −26.7 kPa (−200 mmHg, −7.87 inHg)

Vehicle speed

≥ 32 km/h (20 MPH)

Fuel level

9 ←→ 51 litres (2.38 ←→ 13.47 US gal, 1.98 ←→ 11.22 Imp gal)

Closed air/fuel ratio control

In operation

Fuel temperature

−10 ←→ 45°C (14 ←→ 113°F)

Intake air temperature

≥ −10°C (14°F)

Pressure change per second

< 0.13 kPa (0.95 mmHg, 0.04 inHg)

Min. pressure change per second − Max. pressure change per second

< 0.23 kPa (1.7 mmHg, 0.07 inHg)

Fuel level change

< 2.5 litres(2.1 US qt, 1.8 Imp gal)/128 milliseconds

Air fuel ratio

> 0.76 — 1.25



0.02-inch Diagnosis

Secondary Parameters Enable Conditions
(At starting a diagnosis)

Evaporation diagnosis

Not completed

Battery voltage

≥ 10.9 V

Atmospheric pressure

≥ 75.1 kPa (563 mmHg, 22.2 inHg)

Since last incomplete diagnosis event of 0.02-inch leakage

> 600 seconds

Cumulative time of canister purge

120 seconds or more

After engine starting

770 second or more

Fuel temperature

−10 ←→ 70°C (14 ←→ 158°F)

Fuel level

9 ←→ 51 litres (2.38 ←→ 13.47 US gal, 1.98 ←→ 11.22 Imp gal)

Intake manifold vacuum (relative pressure)

< −8.0 kPa (−60 mmHg, −2.36 inHg)

Fuel tank pressure

−0.67 — 1.43 kPa (−5 — 10.7 mmHg, −0.20 — 0.42 inHg)

Vehicle speed

≥ 68 km/h (42 MPH)

Closed air/fuel ratio control

In operation

Engine speed

550 ←→ 6,000 rpm

(During diagnosis)

Fuel level change

≤ 4.2litres (4.4 US qt, 3.7 Imp qt)

Pressure change per second

< 0.06 kPa (0.44 mmHg, 0.02 inHg)

Min. tank pressure change per second − Max. tank pressure change per second

< 0.07 kPa (0.51 mmHg, 0.02 inHg)

|Tank pressure change per second|

≤ 0.1 kPa (0.75 mmHg, 0.03 inHg)

Pressure change (Mode D)

−0.47 ←→ 0.32 kPa (−3.5 ←→ 2.4 mmHg, −0.14 ←→ 0.09 inHg)

Pressure change (Mode E)

−0.32 ←→ 0.32 kPa (−2.4 ←→ 2.4 mmHg, −0.09 ←→ 0.09 inHg)



GENERAL DRIVING CYCLE

0.04-inch Diagnosis


Perform the diagnosis only once in more than 856 seconds after the engine start at the constant driving speed of 32 km/h (20 MPH) or more.

Pay attention to the fuel temperature and fuel level.


0.02-inch Diagnosis


Perform diagnosis in more than 770 seconds after engine start at the constant speed of 68 km/h (42 MPH) or more, and judged OK or NG.

If not judged OK or NG, repeat the diagnosis.

Pay attention to the fuel level.


DIAGNOSTIC METHOD

Purge control solenoid valve open malfunction diagnosis

DTC

P0457 Evaporative Emission Control System Leak Detected (fuel cap loose/off)

Purpose of Mode Z

When performing the leakage diagnosis of EVAP system, CPC has to operate normally. Therefore, mode Z is used to diagnose the CPC open fixation.

If the CPC open fixation trouble is detected, the EVAP system leakage diagnosis is cancelled.

Diagnostic method

CPC functional diagnosis is performed by monitoring the tank pressure in Mode Z.

Normality Judgment

Judge OK when the following criteria are satisfied in 3 seconds after Mode Z started, and change to Mode A.

Judgment Value

Malfunction Criteria Threshold Value DTC
(Tank pressure when Mode Z started) — (Tank pressure when Mode Z finished)

≤ 0.4 kPa (3 mmHg, 0.12 inHg)

P0457



Normal Operation


(1)

Mode Z

(3)

Fuel tank pressure

(5)

OK judgement

(2)

3 seconds

(4)

0.4 kPa (3.0 mmHg, 0.12 inHg)




evptez − evptezha ≤ 0.4 kPa (3.0 mmHg, 0.12 inHg)

evptezini − evptezha ≤ 0.4 kPa (3.0 mmHg, 0.12 inHg)


Judge normal when both calculations are completed.

Abnormality Judgment

If OK judgment cannot be made, extend Mode Z 16 seconds more, and judge NG when all the criteria below are completed in 16 seconds.

Judgment Value

Malfunction Criteria Threshold Value DTC
(Tank pressure when Mode Z started) − (Tank pressure when Mode Z finished)

> 0.6 kPa (4.5 mmHg, 0.18 inHg)

P0457

Tank pressure when Mode Z started

≤ 1.43 kPa (10.7 mmHg, 0.42 inHg)

TIme for no fuel rolling of 2litres or more

≥ 40 seconds



Time Needed for Diagnosis: 16 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

Finish the Evap. diagnosis when making NG judgment for purge control solenoid valve open fixation.

Cancel the Evap. diagnosis when the OK/NG judgment for purge control solenoid valve open fixation cannot be made in Mode Z.

Purge Control Solenoid Valve Open Fixation


(1)

Mode Z

(4)

Fuel tank pressure

(7)

No fuel rolling for more than 40 seconds

(2)

Extended mode Z

(5)

0.87 kPa (6.5 mmHg, 0.26 inHg)

(3)

16 seconds

(6)

1.43 kPa (10.7 mmHg, 0.42 inHg)

(8)

NG judgement




evptezini, evptez ≤ 1.43 kPa (10.7 mmHg, 0.42 inHg)

evptez − evptezha ≤ 0.87 kPa (6.5 mmHg, 0.26 inHg)

evptezini − evptezha ≤ 0.87 kPa (6.5 mmHg, 0.26 inHg)

No fuel rolling of above 2litres(0.79 US gal, 0.67 Imp gal) for more than 40 seconds.


Judge normal when all the calculations are completed.

Leak Diagnosis

DTC

P0442 Evaporative Emission Control System Leak Detected (small leak)

P0457 Evaporative Emission Control System Leak Detected (fuel cap loose/off)

Diagnostic method


The diagnostic method consists of creating a sealed vacuum in the fuel tank and then determining the presence of leakage from the speed at which the tank internal pressure returns to atmospheric pressure.

The diagnosis is divided into the following five phases.


Mode A: (Estimation of evaporation gas yield)

The amount of change of tank pressure (P1) in Mode A is calculated. After calculating P1, change to Mode B.

Mode B: (Seal negative pressure)

Introduce the negative pressure in the intake manifold to the tank.

Approx. 0 → −1.4 kPa (0 → −10.5 mmHg, 0 → −0.41 inHg)

When the pressure above (desired negative pressure) is reached, Mode C is entered.

In this case, if the tank pressure does not become the desired negative pressure, judge that there is a large leakage in the system, finish the Evap. diagnosis when judging large leak (10 or 25 seconds).

Abnormality Judgment

Judge NG (large leak) when the criteria below are completed in the specified time.

Judgment Value

Malfunction Criteria Threshold Value DTC
P0457

Time before reaching desired negative pressure

≥ 25 seconds

Or time for Mode B

≥ 10 seconds

(Min. value of tank pressure during Mode B) − (Tank pressure when Mode B started)

< −0.3 kPa (−4 mmHg, −0.16 inHg)



Mode C: (Check increasing pressure)

Stop the introduction of negative pressure. (Wait until the tank pressure returns to the start level of P2 calculation.)

Change to Mode D when the tank pressure returns to the start level of P2 calculation.

Judge immediate OK and change to Mode E when it does not return in spite of spending the specified time.

Tank pressure when P2 calculation started Time for immediate OK judgment
−1.3 kPa (−9.75 mmHg, −0.38 inHg)

15 seconds



Mode D: (Measurement of negative pressure changes)

Monitor the pressure variation in the tank in Mode Z. In this case, the tank pressure increases, that is, the pressure becomes as high as the atmospheric air pressure, because evaporator is generated. However, if any leakage exists, the pressure increases additionally in proportion to this leakage. The pressure variation of this tank is P2.

After calculating P2, perform following small leak diagnosis.

After Mode D

Assigning P1 and P2, which are tank variations measured in Mode A and Mode B, to the formula below, judge the small leakage of the system. If the measured judgment value exceeds the threshold value, it is judged to be malfunction.

Abnormality Judgment

Judge NG when the criteria below are completed. Judge OK when not completed and clear the NG.

Judgment Value

Malfunction Criteria Threshold Value DTC
P2 − 1.5 × P1

> Value on map 7. *Threshold value: Map (Fuel level vs Tank temperature)

P0442

P2: Change of tank pressure within 10 seconds on Mode D

P1: Change of tank pressure within 10 seconds on Mode A



*1.5: Compensation value of the amount of evaporator occurrence. (Because evaporator increases more when becoming negative pressure.)

Map 7 Limit of malfunction criteria as Evap. diagnosis.

Fuel temperature vs Fuel level 5°C (41°F) 15°C (59°F) 25°C (77°F) 35°C (95°F) 45°C (113°F)
10 L (2.6 US gal, 2.2 Imp gal)

0.49 kPa

(3.68 mmHg, 0.145 inHg)

0.49 kPa

(3.68 mmHg, 0.145 inHg)

0.50 kPa (3.75 mmHg, 0.148 inHg)

0.54 kPa

(4.07 mmHg, 0.160 inHg)

0.56 kPa

(4.17 mmHg, 0.164 inHg)

20 L (5.3 US gal, 4.4 Imp gal)

0.50 kPa (3.77 mmHg, 0.148 inHg)

0.51 kPa (3.79 mmHg, 0.149 inHg)

0.53 kPa

(4.01 mmHg, 0.158 inHg)

0.56 kPa

(4.17 mmHg, 0.164 inHg)

0.57 kPa

(4.27 mmHg, 0.168 inHg)

30 L (7.9 US gal, 6.6 Imp gal)

0.51 kPa (3.85 mmHg, 0.152 inHg)

0.51 kPa (3.79 mmHg, 0.149 inHg)

0.54 kPa

(4.06 mmHg, 0.160 inHg)

0.57 kPa

(4.27 mmHg, 0.168 inHg)

0.60 kPa

(4.48 mmHg, 0.176 inHg)

40 L (10.6 US gal, 8.8 Imp gal)

0.65 kPa (4.88 mmHg, 0.192 inHg)

0.65 kPa (4.90 mmHg, 0.193 inHg)

0.66 kPa (4.98 mmHg, 0.196 inHg)

0.71 kPa (5.32 mmHg, 0.209 inHg)

0.76 kPa (5.73 mmHg, 0.226 inHg)

50 L (13.2 US gal, 11.0 Imp gal)

0.79 kPa

(5.90 mmHg, 0.232 inHg)

0.79 kPa

(5.90 mmHg, 0.232 inHg)

0.79 kPa

(5.90 mmHg, 0.232 inHg)

0.85 kPa

(6.38 mmHg, 0.251 inHg)

0.88 kPa

(6.60 mmHg, 0.260 inHg)



Time Needed for Diagnosis: 30 — 100 Seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous drive cycles.

Leak diagnosis

DTC

P0456 Evaporative Emission Control System Leak Detected (very small leak)

Diagnostic method


The diagnostic method consists of creating a sealed vacuum in the fuel tank and then determining the presence of leakage from the speed at which the tank internal pressure returns to atmospheric pressure.

The diagnosis is divided into the following five phases.


Mode A: (0 point correction)

Wait until the tank pressure returns to 0 point (near 0 mmHg) when tank pressure is high. Then change to Mode B. If the tank pressure does not return to 0 point in the specified time, cancel the diagnosis.

Mode B: (Negative pressure introduction)

Introduce the negative pressure in the intake manifold to the tank.

Approx. 0 → −2.0 kPa (0 → −15 mmHg, 0 → −0.59 inHg)

When the pressure above (desired negative pressure) is reached, Mode C is entered.

In this case, if the tank pressure does not become the desired negative pressure, cancel the diagnosis.

Mode C: (Holding negative pressure)

Stop the introduction of negative pressure. (Wait until the tank pressure returns to the start level of P2 calculation.)

Change to Mode D when the tank pressure returns to the start level of P2 calculation, or when spending the specified time.

Mode D: (Calculation of negative pressure variation)

By monitoring the tank pressure at Mode D, calculate the pressure variation (P2) and measure the time (evpdset) it takes the tank pressure to return to the detection completing pressure of P2. Then change to Mode E. When the tank pressure does not return to the detection completing pressure of P2 in the specified time, make advanced OK judgment or cancel the diagnosis according to P2 value.

Normality judgment

Judge OK when the following criteria are satisfied.

Judgment Value

Malfunction Criteria Threshold Value
Advanced OK judgment 1

Mode D holding time

≥ 30 seconds

Tank pressure

≤ −1.8 kPa (−13.4 mmHg, −0.53 inHg)

Advanced OK judgment 2

Mode D holding time

≥ 200 seconds

P2

≤ 0.9 — 1.3 kPa

(7 — 9.6 mmHg, 0.28 — 0.38 inHg)



Mode E (Calculation of yielded evaporation amount)

Calculate the pressure variation (P1) at the time (evpdset), and make NG/OK judgment according to P1 value (ambiguous determination acceptable).

Abnormality Judgment

Judge NG when the following criteria are satisfied.

Judgment Value

Malfunction Criteria Threshold Value
P1

< Value from Map 7

* Threshold value: Map (Fuel level vs evpdset)



Map 7 Limit of malfunction criteria as Evap. diagnosis

Time (evpdset) vs Fuel level 0 seconds 30 seconds 80 seconds 100 seconds 150 seconds 200 seconds
10 L (2.6 US gal, 2.2 Imp gal)

0 kPa (0 mmHg, 0 inHg)

0.21 kPa (1.6 mmHg, 0.063 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

30 L (7.9 US gal, 6.6 Imp gal)

0 kPa (0 mmHg, 0 inHg)

0.21 kPa (1.6 mmHg, 0.063 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0 kPa (0 mmHg, 0 inHg)

50 L (13.2 US gal, 11.0 Imp gal)

0 kPa (0 mmHg, 0 inHg)

0.24 kPa (1.8 mmHg, 0.071 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0.29 kPa (2.2 mmHg, 0.087 inHg)

0 kPa (0 mmHg, 0 inHg)

0 kPa (0 mmHg, 0 inHg)



Normality judgment

Judge OK when the following criteria are satisfied.

Judgment Value

Malfunction Criteria Threshold Value
P1

> Value from Map 8

* Threshold value: Map (Fuel level vs evpdset)



Map 8 Limit of malfunction criteria as Evap. diagnosis

Time (evpdset) vs Fuel level 0 seconds 30 seconds 80 seconds 100 seconds 150 seconds 200 seconds
10 L (2.6 US gal, 2.2 Imp gal)

0.16 kPa (1.2 mmHg, 0.047 inHg)

0.37 kPa (2.8 mmHg, 0.110 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

30 L (7.9 US gal, 6.6 Imp gal)

0.16 kPa (1.2 mmHg, 0.047 inHg)

0.37 kPa (2.8 mmHg, 0.110 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

50 L (13.2 US gal, 11.0 Imp gal)

0.16 kPa (1.2 mmHg, 0.047 inHg)

0.40 kPa (3 mmHg, 0.118 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)

0.45 kPa (3.4 mmHg, 0.134 inHg)



Time Needed for Diagnosis: 540 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous drive cycles.

DTC CLEAR CONDITION


When the OK idling cycle was completed 40 times in a row

When “Clear Memory” was performed


MALFUNCTION INDICATOR LIGHT CLEAR CONDITION


When the OK driving cycle was completed 3 times in a row

When “Clear Memory” was performed


FAIL SAFE

None

ECM OPERATION AT DTC SETTING


Memorize the freeze frame data. (For test mode $02)

Memorize the diagnostic value and trouble standard value. (For test mode $06)