Page 1289 of 3115

A19522A19630
VC
E2(+)
(-) E5
ECM Connector
A19627A19432
A19637
E2PTNK
Vacuum Disconnect(+)
(-) E5
E9
DI-240
- DIAGNOSTICSENGINE
433 Author: Date:
11 Check voltage between terminals VC and E2 of ECM connector.
CHECK:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals the E5 ECM connector.
OK:
Tester ConnectionSpecified Condition
VC (E5-18) - E2 (E5-28)4.5 to 5.5 V
NG Replace ECM (See page SF-60).
OK
12 Check voltage between terminals PTNK and E2 of ECM connectors.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals PTNK and E2 of the
ECM connectors at following condition (1) and (2).
(1) Disconnect the vacuum hose from the vapor pres-
sure sensor.
(2) Using the MITYVAC (Hand-Held Vacuum Pump),
apply a vacuum of 4.0 kPa (30 mmHg, 1.18 in.Hg)
to the vapor pressure sensor.
NOTICE:
The vacuum applied to the vapor pressure sensor must be
less than 66.7 kPa (500 mmHg, 19.7 in.Hg).
OK:
Condition (1) Voltage: 2.9 to 3.7 V
Condition (2) Voltage: 0.5 V or less
OK Go to step 14.
NG
Page 1290 of 3115
A19638
PRG
Air Air
FF EE
VSV is ON VSV is OFF
E5
- DIAGNOSTICSENGINE
DI-241
434 Author: Date:
13 Check for open and short in harness and connector between vapor pressure sen-
sor
and ECM (See page IN-36).
NG Repair or replace harness or connector.
OK
Replace ECM (See page SF-60).
14 Check EVAP VSV.
PREPARATION:
(a) Remove the glove compartment door (See page
SF-60).
(b) Turn the ignition switch ON.
CHECK:
Check the VSV function.
(1) Connect between terminal PRG of the ECM con-
nector and body ground (ON).
(2) Disconnect between terminal PRG of the ECM con-
nector and body ground (OFF).
OK:
(1) VSV is ON:
Air from port E flows out through port F.
(2) VSV is OFF:
Air does not flow from port E to port F.
OK Go to step 17.
NG
15 Check operation of EVAP VSV (See page SF-44).
NG Replace EVAP VSV.
OK
Page 1291 of 3115
A19639VSV is OFF VSV is ON CCV
Air
E Air
E
FF
E5
DI-242
- DIAGNOSTICSENGINE
435 Author: Date:
16 Check for open and short in harness and connector between EFI or ECD relay
and EVAP VSV, and EVAP VSV and ECM (See page IN-36).
NG Repair or replace harness or connector.
OK
Replace ECM (See page SF-60).
17 Check CCV.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Check the VSV function.
(1) Connect the terminal CCV of the ECM connector
and body ground (ON).
(2) Disconnect the terminal CCV of the ECM connector
and body ground (OFF).
OK:
(1) VSV is ON:
Air does not flow from port E to port F.
(2) VSV is OFF:
Air from port E flows out through port F.
OK Go to step 20.
NG
18 Check operation of CCV (See page SF-48).
NG Replace CCV.
OK
Page 1292 of 3115
A19641VSV is ON VSV is OFFTBP
Air
E Air
E
FF
E9
- DIAGNOSTICSENGINE
DI-243
436 Author: Date:
19 Check for open and short in harness and connector between EFI or ECD relay
and CCV, and CCV and ECM (See page IN-36).
NG Repair or replace harness or connector.
OK
Replace ECM (See page SF-60).
20 Check pressure switching valve.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Check the VSV function.
(1) Connect the terminal TBP of the ECM connector
and body ground (ON).
(2) Disconnect the terminal TBP of the ECM connector
and body ground (OFF).
OK:
(1) VSV is ON:
Air does not flow from port E to port F.
(2) VSV is OFF:
Air from port E flows out through port F.
OK Go to step 23.
NG
21 Check operation of pressure switching valve (See page SF-46).
NG Replace pressure switching valve.
OK
Page 1293 of 3115
DI-244
- DIAGNOSTICSENGINE
437 Author: Date:
22 Check for open and short in harness and connector between EFI or ECD relay
and pressure switching valve, and pressure switching valve and ECM (See page
IN-36).
NG Repair or replace harness or connector.
OK
Replace ECM (See page SF-60).
23 Check fuel tank inlet valve.
NG Replace fuel tank inlet valve.
OK
24 Check fuel tank.
NG Replace fuel tank.
OK
It is likely that vehicle user did not properly
close fuel tank cap.
Page 1294 of 3115
A19378A20057
ECM
EVAP VSV
Charcoal Canister
Fuel Tank Fig. 1
(2)
(3) (4) (6)
(8)
(9) (1)
(5)
(7)Vapor Pressure
Sensor
CCVPressure
Switching
Valve
- DIAGNOSTICSENGINE
DI-245
438 Author: Date:
DTC P0442 Evaporative Emission Control System Leak
Detected (Small Leak)
DTC P0455 Evaporative Emission Control System Leak
Detected (Gross Leak)
DTC P0456 Evaporative Emission Control System Leak
Detected (Very Small Leak)
CIRCUIT DESCRIPTION
The vapor pressure sensor, canister closed valve (CCV) and pressure switching valve are used to detect
abnormalities in the evaporative emission control system.
The ECM decides whether there is an abnormality in the evaporative emission control system based on the
vapor pressure sensor signal.
DTC P0442, P0455 or P0456 is recorded by the ECM when evaporative emissions leak from the compo-
nents within the dotted line in Fig. 1 below, or when the vapor pressure sensor malfunctions.
DIC2I-01
Page 1295 of 3115

A21544
CCV
Pressure Switching Valve
EVAP VSV
Cold Start
ECT/IAT near same temp.Open
ClosedOpen ClosedOpen
Closed
Closed
Closed Open
P0441, P0446,
P0455, P2418
Negative Pressure
OccursP0442, P0456
Tank & Canister
Leak CheckP0446
Pressure Switching
Valve Testing
(ex. Fuel tank cap loose)
(ex. Disconnect of vacuum hose)
P2418
CCV
Testing
Pressure
Switching
valve open
malfunction
(P2418)
(P0455) Gross Leak
P0442
P0456
DI-246
- DIAGNOSTICSENGINE
439 Author: Date:
MONITOR DESCRIPTION
A leak in the evaporative emission system prompts the ECM to set DTC P0442, P0455 or P0456.
The ECM checks for leaks in the system by introducing a high negative pressure (vacuum) from the intake
manifold by commanding the EVAP VSV open while the CCV (vent) is closed and the pressure switching
valve is open. After sufficient time has elapsed the fuel tank should have developed a high negative pressure
(vacuum) and the EVAP VSV closed. The ECM then monitors the pressure-rise (loss of vacuum) in the fuel
tank. If the pressure rises too rapidly, the ECM concludes that there is a leak in the system. The ECM will
turn on the MIL and set a DTC.
The ECM has separate DTCs for small and large leaks:
(1) DTC P0442 is set when the internal fuel tank pressure has a large increase and the EVAP system
has a small leak.
(2) DTC P0455 is set when the EVAP system has various large leaks. Even though the ECM sends
a signal to the EVAP VSV (when CCV is closed) to create a vacuum, the internal fuel tank pres-
sure does not decrease beyond a specified level.
(3) DTC P0456 is set when the internal fuel tank pressure increase slightly and the EVAP system
has a small leak.
Page 1296 of 3115

- DIAGNOSTICSENGINE
DI-247
440 Author: Date:
HINT:
Refer to DTCs P0441, P0446 and P2418
DTC No.DTC Detecting ConditionTrouble Area
P0442After the negative pressure introduction has been completed, if
the pressure in the EVAP system sharply increases.
After the negative pressure introduction has been completed, if
the pressure in the EVAP system sharply increases.
Hose or tube cracked, holed, damaged or loose seal ((3) in
Fig. 1)
Fl k i li lld
P0455If the vacuum is not strong enough, the ECM assumes the
EVAP system has a large hole.
Fuel tank cap incorrectly installed
Fuel tank cap cracked or damaged
Vacuum hose cracked, holed, blocked, damaged or discon-
nected ((1), (2), (4), (5), (6), (7), (8) and (9) in Fig. 1)
Fuel tank cracked, holed or damaged
P0456If the pressure in the EVAP system slightly increase while the
ECM performs a leak check.
Fuel tank cracked, holed or damaged
Charcoal canister cracked, holed or damaged
Open or short in vapor pressure sensor circuit
Vapor pressure sensor
ECM
HINT:
Typical DTC output of each trouble part
Trouble partTypical DTC output (*1)
Small LeakP0442 and/or P0456
Medium Leak (ex: Vacuum hose loose)P0455
Large Leak (ex: Fuel tank cap loose)P0441, P0446, P0455 and P2418
EVAP VSVOpen MalfunctionP0441EVAP VSVClose MalfunctionP0441, P0446, P0455 and P2418
CCVOpen MalfunctionP0441, P0446, P0455 and P2418CCVClose MalfunctionP0446
PSithiVlOpen MalfunctionP2418Pressure Switching ValveClose MalfunctionP0441, P0446, P0455 and P2418
*1: ECM may output some other DTC combination.
MONITOR STRATEGY
P0442Small leak (0.040 inch or more large hole) is de-
tected
Related DTCsP0455Gross leak detected
P0456Very small leak (0.020 inch hole) is detected
Main sensors/componentsVapor pressure sensor
Required sensors/componentsRelated sensors/components
Mass air flow sensor, Engine coolant temperature
sensor
EVAP VSV (purge VSV), CCV
Frequency of operationOnce per drive cycle
Duration60 sec.
MIL operation2 drive cycles
Sequence of operationNone