1998 MITSUBISHI MONTERO Fuel Pump

Fig. 2: ASD/Fuel Pump/MFI Relay Terminals (All Other Models)
Courtesy of Mitsubishi Motor Sales of America

Fig. 14: Identifying Fuel Pump Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America
Fig. 15: Identifying Fuel Pump Terminals (3000GT)
Courtesy of Mitsubishi Motor Sales of America

Fig. 16: Identifying Fuel Pump Control/Relay Module Terminals
Courtesy of Mitsubishi Motor Sales of America
Fig. 17: Identifying FTDP Sensor Terminals
Courtesy of Mitsubishi Motor Sales of America
Fig. 18: Identifying Generator Field Terminals
Courtesy of Mitsubishi Motor Sales of America

continuity between chassis ground and EGR solenoid connector terminal
No. 2. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, condition required to set DTC is not
present at this time. Go to next step.
12) Test is complete. Intermittent problem may exist. Road
test vehicle (if necessary) and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
go to INTERMITTENT DTCS .
DTC P0420, P0421 & P0431: CATALYST EFFICIENCY BELOW
THRESHOLD
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
Specific self-diagnostic test not available from manufacturer
at time of publication. Check catalytic converter and check for
cracked exhaust manifold. Also, see F - BASIC TESTING article.
DTC P0442: EVAPORATIVE (EVAP) EMISSION CONTROL SYSTEM LEAK
DETECTED
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Remove fuel cap. Push fuel pipe restrictor to operate On-
board Fuel Vent Valve (OFLV). Install and tighten fuel cap. Remove
fuel cap and ensure distance between filler tube and OFLV is 1.1" (28
mm). If distance is as specified, go to next step. If distance is not
as specified, replace fuel tank filler tube assembly. Go to step 24).
2) Disconnect and plug air filter-to-EVAP vent solenoid hose
at air filter. Disconnect intake manifold plenum-to-EVAP purge
solenoid at intake manifold plenum. Install a "T" fitting between
vacuum hose and intake manifold plenum. Connect a hand-held
pressure/vacuum pump to "T" fitting. Go to next step.
CAUTION: DO NOT apply more than 0.57 psi in following step. Applying
more than specified psi can crack fuel tank.
NOTE: Ensure fuel tank is at least 1/4 full. The lower the fuel
level in fuel tank, the longer it takes to pressurize fuel
system.
3) Using scan tool, read Fuel Tank Differential Pressure
(FTDP) sensor (item 73). Using hand-held pressure/vacuum pump, apply\
0.42 psi. If scan tool reading reaches 0.42 psi, go to next step. If
reading does not reach 0.42 psi, go to step 9).
4) Wait 20 seconds and read scan tool. If scan tool reading
increases 0.06 psi or less, go to next step. If scan tool reading
increases more than 0.06 psi, go to step 21).
5) Disconnect EVAP canister purge hose. Connect Purge Flow
Indicator (MB995061) between EVAP canister and disconnected hose. Turn\
engine on and allow it to reach operating temperature. Turn all lights
and accessories off. Place transmission in Park or Neutral. Observe
purge flow indicator while increasing engine RPM several times. If
purge flow indicator reads less than 2.5 SCFH (20 cm(3)/sec), check
EVAP canister purge hose and EVAP canister port for clogging. If hose
and port are okay, check EVAP purge solenoid. See DTC P0443. If
solenoid is okay, replace EVAP canister. Go to step 24).
6) Using scan tool, read Engine Coolant Temperature (ECT)
sensor temperature (item 21). Compare scan tool reading with

temperature gauge reading. If readings are about the same, go to next
step. If readings are not about the same, go to DTC P0115 test.
7) Using a thermometer, check engine compartment ambient
temperature. Using scan tool, read Intake Air Temperature (IAT) sensor\
temperature (item 13). Compare IAT sensor and thermometer readings. If\
readings are not about the same, go to DTC P0110 test. If readings are
about the same, go to next step.
8) Using scan tool, read Power Steering Pressure (PSP) switc\
h
status (item 27). Switch status should read ON when steering wheel is
turned. If switch status is as specified, go to step 24). If switch
status is not as specified, go to DTC P0551 test.
9) Remove fuel cap. Install a fuel tank filler tube adapter
in place of fuel cap. Plug fuel filler tube adapter hose. Disconnect
and plug air filter-to-EVAP vent solenoid hose at air filter.
Disconnect intake manifold plenum-to-EVAP purge solenoid at intake
manifold plenum. Install a "T" fitting between vacuum hose and intake
manifold plenum. Connect hand-held pressure/vacuum pump to "T"
fitting. Go to next step.
CAUTION: DO NOT apply more than 0.57 psi in following step. Applying
more than specified psi can crack fuel tank.
NOTE: Ensure fuel tank is at least 1/4 full. The lower the fuel
level in fuel tank, the longer it takes to pressurize fuel
system.
10) Using scan tool, read Fuel Tank Differential Pressure
(FTDP) sensor (item 73). Using hand-held pressure/vacuum pump, apply\
0.42 psi. If scan tool reading reaches 0.42 psi, replace fuel cap. Go
to step 24). If reading does not reach 0.42 psi, go to next step.
11) Disconnect hand-held pressure/vacuum pump from "T"
fitting. Install an evaporative emission system tester in place of
vacuum held pump and apply 0.49 psi. Wait two minutes. If pressure
drops less than 0.20 psi, go to next step. If pressure drops 0.29 psi
or more, go to step 14).
12) Disconnect EVAP purge solenoid-to-EVAP canister hose at
EVAP canister. Connect hand-held pressure/vacuum pump to hose and
apply 0.9 psi. If pressure is not maintained, check EVAP purge
solenoid for leak. If EVAP purge solenoid is okay, replace hose. Go to
step 24). If pressure is maintained, go to next step.
13) Disconnect EVAP vent solenoid-to-EVAP canister hose at
EVAP canister. Connect hand-held pressure/vacuum pump to hose and
apply 0.9 psi. If pressure is not maintained, check EVAP vent solenoid
for leak. If EVAP vent solenoid is okay, replace hose. Go to step 24).
If pressure is maintained, replace EVAP canister. Go to step 24).
14) Ensure hoses are properly routed and connected. See M -
VACUUM DIAGRAMS article. Install hoses as necessary and go to step
24). If hoses are okay, go to next step.
15) Disconnect OFLV-to-EVAP canister hose at OFLV and EVAP
canister. Plug hose at OFLV end. Connect hand-held pressure/vacuum
pump to hose at EVAP canister end. Apply 0.9 psi. If pressure is not
maintained, replace hose. Go to step 24). If pressure is maintained,
go to next step.
16) Using scan tool, read Fuel Tank Differential Pressure
(FTDP) sensor (item 73). Connect hand-held pressure/vacuum pump to
OFLV. While monitoring scan tool, apply 0.42 psi. If scan tool reading
reaches 0.42 psi, go to next step. If reading does not reach 0.42 psi,
go to step 20).
17) Disconnect OFLV-to-EVAP canister hose at EVAP canister.
Connect hand-held pressure/vacuum pump to hose and apply 0.9 psi. If
pressure is not maintained, go to next step. If pressure is
maintained, go to step 19).
18) Disconnect EVAP purge solenoid-to-EVAP canister hose at

EVAP canister. Connect hand-held pressure/vacuum pump to hose.
Disconnect intake manifold plenum-to-EVAP purge solenoid at intake
manifold plenum. Operate vacuum pump several times to apply vacuum. If
vacuum leaks, replace EVAP canister. Go to step 24). If vacuum does
not leak, repair clog in hose between EVAP canister and EVAP Purge
solenoid. Go to step 24).
19) Disconnect EVAP canister-to-OFLV hose at OFLV. If vacuum
does not leak, repair clog in hose between EVAP canister and OFLV. Go
to step 24). If vacuum leaks, check fuel tank filler tube assembly. If
fuel tank filler tube assembly is okay, repair clog in hose between
OFLV and fuel cut-off valve. Go to step 24).
20) Replace fuel tank filler tube and OFLV-to-fuel cut-off
valve hose. While monitoring scan tool, apply 0.42 psi with hand-held
pressure/vacuum pump. If scan tool reading does not reach 0.42 psi,
replace fuel tank. Go to step 24).
21) Remove fuel cap. Install a fuel tank filler tube adapter
in place of fuel cap. Disconnect and plug air filter-to-EVAP vent
solenoid hose at air filter. Plug fuel filler tube adapter hose.
Disconnect intake manifold plenum-to-EVAP purge solenoid at intake
manifold plenum. Install a "T" fitting between vacuum hose and intake
manifold plenum. Connect hand-held pressure/vacuum pump to "T"
fitting. Go to next step.
CAUTION: DO NOT apply more than 0.57 psi in following step. Applying
more than specified psi can crack fuel tank.
NOTE: Ensure fuel tank is at least 1/4 full. The lower the fuel
level in fuel tank, the longer it takes to pressurize fuel
system.
22) Using scan tool, read Fuel Tank Differential Pressure
(FTDP) sensor (item 73). Using hand-held pressure/vacuum pump, apply\
0.42 psi. If scan tool reading rises 0.06 psi or less, replace fuel
cap. Go to step 24). If reading rises more than 0.06 psi, go to next
step.
23) Disconnect hand-held pressure/vacuum pump from "T"
fitting. Install an evaporative emission system tester in place of
vacuum held pump and apply 0.49 psi. Using an ultrasonic leak
detector, locate and repair leaks. Go to next step.
24) Road test vehicle and attempt to duplicate conditions
that caused original complaint. Recheck for DTCs. If no DTCs are
displayed, test is complete.
DTC P0443: EVAPORATIVE (EVAP) EMISSION CONTROL SYSTEM PURGE
CONTROL VALVE CIRCUIT MALFUNCTION
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Using scan tool, turn EVAP purge solenoid on and off (item\
08). Listen for clicking sound from EVAP purge solenoid. If no sound
is heard, go to next step. If sound is heard, fault is intermittent.
See INTERMITTENT DTCS .
2) Mark and disconnect vacuum hoses, and wiring connector
from EVAP purge solenoid. Install vacuum pump to EVAP purge solenoid
Black/Red vacuum hose port. Apply vacuum to EVAP purge solenoid. Go to
next step.
3) Apply and remove 12 volts across EVAP purge solenoid
terminals. Vacuum should hold without voltage applied. Vacuum should
leak with voltage applied. If EVAP purge solenoid does not test as
specified, replace EVAP purge solenoid. Go to step 8). If EVAP purge
solenoid tests as specified, go to next step.

4) Using DVOM, check resistance across EVAP purge solenoid
terminals. If resistance is not 36-44 ohms at 68F (20C), replace
EVAP purge solenoid. Go to step 8). If resistance is as specified, go
to next step.
5) On 3000GT, go to next step. On Montero, disconnect EVAP
purge solenoid connector and MFI relay connector. Using DVOM, check
continuity between EVAP purge solenoid connector terminal No. 1 and
MFI relay connector terminal No. 1. If continuity does not exist,
repair wiring harness as necessary. If continuity exists, go to step
7).
6) Disconnect EVAP purge solenoid connector. Using DVOM,
check voltage between chassis ground and EVAP purge solenoid connector
terminal No. 1. If battery voltage does not exist, repair wiring
harness as necessary. If battery voltage exists, go to next step.
7) Turn ignition switch to OFF position. Disconnect PCM
connector. Ground PCM connector terminal No. 16. Using DVOM, check for
continuity between chassis ground and EVAP purge solenoid connector
terminal No. 2. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, condition required to set DTC is not
present at this time. Go to next step.
8) Road test vehicle and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
test is complete.
DTC P0446: EVAPORATIVE (EVAP) EMISSION CONTROL SYSTEM VENT
CONTROL MALFUNCTION
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Using scan tool, turn EVAP vent solenoid on and off (item
29). Listen for clicking sound from EVAP vent solenoid. If no sound is
heard, go to next step. If sound is heard, fault is intermittent. See
INTERMITTENT DTCS .
2) Disconnect EVAP vent solenoid connector and MFI relay
connector. Using DVOM, check continuity between EVAP vent solenoid
connector terminal No. 1 and MFI relay connector terminal No. 1. If
continuity does not exist, repair wiring harness as necessary. If
continuity exists, go to next step.
3) Turn ignition switch to OFF position. Disconnect PCM
connector. Ground PCM connector terminal No. 35. Using DVOM, check for
continuity between chassis ground and EVAP vent solenoid connector
terminal No. 2. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, condition required to set DTC is not
present at this time. Go to next step.
4) Road test vehicle and attempt to duplicate conditions that
caused original complaint. Recheck for DTCs. If no DTCs are displayed,
test is complete.
DTC P0450: EVAPORATIVE (EVAP) EMISSION CONTROL SYSTEM
PRESSURE SENSOR MALFUNCTION
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Using scan tool, check Fuel Tank Differential Pressure
(FTDP) sensor pressure (item 73). Pressure should be -0.48-0.48 psi.\
If pressure is not as specified, go to next step. If pressure is as
specified, fault is intermittent. See INTERMITTENT DTCS.
2) Remove fuel cap. Install a fuel tank filler tube adapter
in place of fuel cap. Connect a hand-held pressure/vacuum pump to fuel

tank filler adapter hose. Go to next step.
CAUTION: DO NOT apply more than 1.0 psi in following step. Applying
more than specified psi can crack fuel tank.
NOTE: Ensure fuel tank is at least 1/4 full. The lower the fuel
level in fuel tank, the longer it takes to pressurize fuel
system.
3) Apply 1.0 psi. Using scan tool, read Fuel Tank
Differential Pressure (FTDP) sensor (item 73). If scan tool reads mo\
re
than 0.86 psi, go to next step. If reading is 0.86 psi or less, fault
is intermittent. See INTERMITTENT DTCS.
4) Check On-Board Fuel Vent Valve (OFLV) for clogging. OFLV
is located in fuel tank filler tube assembly. If OFLV is clogged,
replace fuel tank filler tube assembly. Go to step 10). If OFLV is
okay, go to next step.
5) Check EVAP hoses, and purge and vent solenoids for
clogging. Repair or replace as necessary. Go to step 10). If hoses and
solenoids are okay, go to next step.
6) Disconnect FTDP connector. Ensure ignition is off. Using
DVOM, check for continuity between ground and FTDP sensor connector
terminal No. 2. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, go to next step.
7) Disconnect PCM connector. Ground PCM connector terminal
No. 93. Using DVOM, check for continuity between chassis ground and
FTDP sensor connector terminal No. 1. If continuity does not exist,
repair wiring harness as necessary. If continuity exists, go to next
step.
8) Turn ignition on. Using DVOM, check voltage between ground
and FTDP sensor connector terminal No. 3. Voltage should be 4.8-5.2
volts. If voltage is not as specified, replace PCM. If voltage is as
specified, go to next step.
9) Inspect connectors and wiring harness between FTDP sensor
and PCM. Repair as necessary. If connectors and wiring harness are
okay, go to next step.
10) Road test vehicle and attempt to duplicate conditions
that caused original complaint. Recheck for DTCs. If no DTCs are
displayed, test is complete.
DTC P0455: EVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM LARGE
LEAK DETECTED
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Remove fuel cap. Push fuel pipe restrictor to operate On-
board Fuel Vent Valve (OFLV). Install and tighten fuel cap. Remove
fuel cap and ensure distance between filler tube and OFLV is 1.1" (28
mm). If distance is as specified, go to next step. If distance is not
as specified, replace fuel tank filler tube assembly. Go to step 20).
2) Disconnect and plug air filter-to-EVAP vent solenoid hose
at air filter. Disconnect intake manifold plenum-to-EVAP purge
solenoid at intake manifold plenum. Install a "T" fitting between
vacuum hose and intake manifold plenum. Connect a hand-held
pressure/vacuum pump to "T" fitting. Go to next step.
CAUTION: DO NOT apply more than 0.57 psi in following step. Applying
more than specified psi can crack fuel tank.
NOTE: Ensure fuel tank is at least 1/4 full. The lower the fuel
level in fuel tank, the longer it takes to pressurize fuel