1998 MITSUBISHI MONTERO engine

PCM or performing resistance tests.
NOTE: Perform all resistance and voltage tests using a Digital
Volt-Ohmmeter (DVOM) with a minimum 10-megohm impedance,
unless stated otherwise in test procedures.
Using scan tool, display and record Diagnostic Trouble DTCs
(DTCs). See ENTERING ON-BOARD DIAGNOSTICS under SELF-DIAGNOSTIC
SYSTEM. If scan tool is blank, see SCAN TOOL WILL NOT COMMUNICATE. If
no DTCs are displayed, see H - TESTS W/O CODES article.
Clear DTCs. See CLEARING DTCS under SELF-DIAGNOSTIC SYSTEM.
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. If one or more DTCs are displayed,
repair DTCs in order, starting with lowest numbered DTC. Clear DTCs
after each repair. Recheck for DTCs to confirm repair.
SCAN TOOL WILL NOT COMMUNICATE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Using DVOM, check voltage between Data Link Connector
(DLC) terminal No. 16 and chassis ground. If battery voltage does not
exist, check and repair junction connectors and wiring harness between
DLC and power supply.
2) If battery voltage exists, check for continuity between
DLC terminal No. 4 and chassis ground, and between DLC terminal No. 5
and chassis ground. If continuity does not exist, check and repair
wiring harness between DLC and chassis ground. If continuity exists,
go to next step.
3) Try a different scan tool adapter cable. If scan tool does
not communicate, try scan tool on a known-good vehicle. If scan tool
still does not communicate, replace scan tool.
INTERMITTENT DTCS
This procedure applies if you have been sent here from
diagnostic tests and have just attempted to simulate the condition
that initially set DTC. The following additional checks may assist in
identifying a possible intermittent problem:
* Visually inspect related wiring harness connectors for
broken, bent, pushed out or corroded terminals.
* Visually inspect related wiring harness for chafed, pierced
or partially broken wires.
* Check all pertinent technical service bulletins.
DTC P0100: VOLUME AIRFLOW (VAF) SENSOR CIRCUIT FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
NOTE: Procedures are provided by manufacturer for component
testing using an engine analyzer with oscilloscope
capability. Refer to manufacturer's operation manual for
instructions in use of oscilloscope.
1) If using scan tool, go to step 3). Disconnect VAF sensor
connector. Install Test Harness (MB991348) between VAF sensor and
connector. Using engine analyzer with oscilloscope capability, connect

special patterns probe to VAF sensor connector terminal No. 3 or to
PCM connector terminal No. 61.
2) Start engine. Verify waveform high frequency and low
frequency patterns are of about the same length (time). Verify
wavelength decreases and frequency increases as engine RPM increases.
If conditions are not as specified, replace VAF sensor. If conditions
are as specified, go to step 4).
3) Warm vehicle to normal operating temperature. Ensure
headlights and accessories are off. Using scan tool, read VAF sensor
frequency value (item 12). See VOLUME AIRFLOW SENSOR VALUES table.
Frequency should increase when engine is raced. If values are not as
specified, replace VAF sensor. If values are as specified, turn
ignition switch to off position and disconnect VAF sensor connector.
Go to next step.
VOLUME AIRFLOW SENSOR VALUES TABLE









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Application Hz @ 700 RPM Hz @ 2500 RPM
Montero ................. 25-51 ................. 80-120
3000GT
DOHC
Non-Turbo ........... 24-50 ................. 71-111
Turbo ............... 26-52 ................. 93-133
SOHC .................. 21-47 .................. 57-97









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4) On 3000GT, go to next step. On Montero, disconnect MFI
relay connector. Using DVOM, check for continuity between VAF sensor
connector terminal No. 4 and MFI relay connector terminal No. 1. If
continuity does not exist, repair wiring harness as necessary. If
continuity exists, go to next step.
5) Using DVOM, check for continuity between chassis ground
and VAF sensor connector terminal No. 5. If continuity does not exist,
repair wiring harness as necessary. If continuity exists, go to next
step.
6) Ensure ignition switch is in OFF position. Disconnect PCM
connector. Ground PCM connector terminal No. 19. Using DVOM, check for
continuity between chassis ground and VAF sensor connector terminal
No. 7. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, go to next step.
7) On 3000GT, go to next step. On Montero, ground PCM
connector terminal No. 61. Using DVOM, check for continuity between
chassis ground and VAF sensor connector terminal No. 3. If continuity
does not exist, repair wiring harness as necessary. If continuity
exists, turn ignition switch to ON position and go to step 9).
8) Turn ignition switch to ON position. Using DVOM, check
voltage between chassis ground and VAF sensor connector terminal No.
4. If battery voltage does not exist, repair wiring harness as
necessary. If battery voltage exists, go to next step.
9) Using DVOM, check voltage between chassis ground and VAF
sensor connector terminal No. 3. If voltage is not 4.8-5.2 volts,
replace PCM. If voltage is as specified, condition required to set DTC
is not present at this time. Go to next step.
10) 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 P0105: BAROMETRIC (BARO) PRESSURE SENSOR CIRCUIT FAILURE
NOTE: BARO pressure sensor is built into Volume Airflow (VAF)
sensor. For DTC P0105 test purposes, VAF sensor will be

referred to as BARO pressure sensor. For terminal
identification, see VAF sensor under TERMINAL IDENTIFICATION.
For circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Component testing procedure without using scan tool not
available from manufacturer at time of publication. Turn ignition
switch to ON position. Using scan tool, read BARO sensor pressure
(item 25). See BARO PRESSURE SENSOR SPECIFICATIONS table. If pressure
is not as specified, replace BARO pressure sensor. If pressure is as
specified, go to next step.
BARO PRESSURE SENSOR SPECIFICATIONS TABLE









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Altitude in Ft. (M) Pressure in kPa (mmHg)
0 (0) .......................................... 101 (768)
1969 (600) ...................................... 95 (710)
3937 (1200) ..................................... 88 (660)
5906 (1800) ..................................... 81 (610)









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2) Disconnect BARO pressure sensor connector. Using DVOM,
check for continuity between chassis ground and BARO pressure sensor
connector terminal No. 5. If continuity does not exist, repair wiring
harness as necessary. If continuity exists, go to next step.
3) Turn ignition switch to OFF position. With BARO pressure
sensor disconnected, disconnect PCM connector. Ground PCM connector
terminal No. 51. Using DVOM, check for continuity between chassis
ground and BARO pressure sensor connector terminal No. 2. If
continuity does not exist, repair wiring harness as necessary. If
continuity exists on Montero, go to next step. On 3000GT, go to step
5).
4) Ground PCM connector terminal No. 42. Check for continuity
between chassis ground and BARO pressure sensor connector terminal No.
1. If continuity does not exist, repair wiring harness as necessary.
If continuity exists, go to next step.
5) Reconnect PCM connector. With BARO pressure sensor
connector disconnected, turn ignition switch to ON position. Using
DVOM, check for voltage between chassis ground and BARO pressure
sensor connector terminal No. 1. If voltage is not 4.8-5.2 volts,
replace PCM. If voltage is as specified, condition required to set DTC
is not present at this time. Go to next step.
6) 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 P0110: INTAKE AIR TEMPERATURE (IAT) SENSOR CIRCUIT
FAILURE
NOTE: IAT sensor is built into Volume Airflow (VAF) sensor. For
DTC P0110 test purposes, VAF sensor will be referred to as
IAT sensor. For terminal identification, see VAF sensor
under TERMINAL IDENTIFICATION . For circuit and wire color
identification, see L - WIRING DIAGRAMS article.
1) If using scan tool, go to step 3). Disconnect IAT sensor
connector. Using a thermometer, check engine compartment ambient
temperature. Using DVOM, check resistance between IAT sensor terminals
No. 5 and 6. Resistance should be 6000 ohms at 32
F (0C), 2700 ohms
at 68F (20C) or 400 ohms at 176F (80C). If resistance is not as
specified, replace IAT sensor. If resistance is as specified, go to

next step.
2) Using a hair dryer, warm IAT sensor while monitoring DVOM.
Resistance should decrease evenly as temperature rises. If resistance
remains unchanged, replace IAT sensor. If resistance changes, go to
step 4).
3) Turn ignition switch to ON or RUN position. Using a
thermometer, check engine compartment ambient temperature. Using scan
tool, read IAT sensor temperature (item 13). Compare both readings. If\
readings are not about the same, replace IAT sensor. If readings are
about the same, turn ignition off and go to next step.
4) Disconnect IAT sensor connector. Using DVOM, check for
continuity between chassis ground and IAT sensor connector terminal
No. 5. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, go to next step.
5) On 3000GT, go to next step. On Montero, turn ignition
switch to OFF position. With IAT sensor connector disconnected,
disconnect PCM connector. Ground PCM connector terminal No. 62. Check
for continuity between IAT sensor connector terminal No. 6 and chassis
ground. If continuity does not exist, repair wiring harness as
necessary. If continuity exists, go to next step.
6) Reconnect PCM connector. Turn ignition switch to ON
position. Check voltage between IAT sensor connector terminal No. 6
and chassis ground. If voltage is not 4.5-4.9 volts, replace PCM. If
voltage is as specified, replace IAT sensor.
DTC P0115: ENGINE COOLANT TEMPERATURE (ECT) SENSOR FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) If using scan tool, go to step 2). Disconnect ECT sensor
connector. Remove ECT sensor from intake manifold. Submerge
temperature sensing portion of ECT sensor in hot water. Using DVOM,
check resistance across ECT sensor terminals. See
ECT SENSOR RESISTANCE SPECIFICATIONS table. If resistance is not as
specified, replace ECT sensor. If resistance is as specified, go to
step 3).
ECT SENSOR RESISTANCE SPECIFICATIONS TABLE









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Water Temperature Approximate Resistance in Ohms
32
F (0C) .......................................... 5800
68F (20C) ......................................... 2400
104F (40C) ........................................ 1100
176F (80C) ......................................... 300








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2) Turn ignition switch to ON or RUN position. Using a
thermometer, check engine compartment ambient temperature. Using scan
tool, read ECT SENSOR TEMPERATURE (item 21). Compare both readings. If\
readings are not about the same, replace ECT sensor. If readings are
about the same go to next step.
3) Disconnect ECT sensor connector. Using DVOM, check
continuity between chassis ground and ECT sensor connector terminal
No. 2. If continuity does not exist, repair wiring harness as
necessary. If continuity exists on 3000GT, go to step 5). On Montero,
go to next step.
4) Turn ignition switch to OFF position. With ECT sensor
connector disconnected, disconnect PCM connector. Ground PCM connector
terminal No. 44. Check continuity between chassis ground and ECT
sensor connector terminal No. 1. If continuity does not exist, repair

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 P0125: EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL
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 front heated oxygen sensor, fuel
injectors, and related connectors and harnesses. Also, see F - BASIC
TESTING article.
DTC P0130, P0135, P0150 & P0155: FRONT HEATED OXYGEN SENSOR
(HO2S) CIRCUIT FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) If using scan tool, go to step 3). Disconnect front HO2S
connector. Install Test Harness (MB998464) between HO2S and HO2S
connector. Using DVOM, check resistance between specified HO2S
connector heater terminals. See
FRONT HO2S CONNECTOR TERMINAL IDENTIFICATION table. HO2S resistance
should be 11-18 ohms at 68
F (20C). If resistance is not as
specified, replace HO2S. If resistance is as specified, go to next
step.
2) Start and warm engine to operating temperature. Using
jumper wires, apply 12 volts and ground to specified HO2S connector
heater terminals. See FRONT HO2S CONNECTOR TERMINAL IDENTIFICATION
table. Using DVOM, check voltage between specified HO2S connector
output terminals, while repeatedly racing engine. If voltage is not .
6-1.0 volt, replace HO2S. If voltage is .6-1.0 volt, go to step 5).
FRONT HO2S CONNECTOR TERMINAL IDENTIFICATION TABLE









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Application (1) Heater Terminals No. Output Terminals No.
Montero & 3000GT ......... 1 & 3 ........................... 2 & 4
( 1) - First terminal listed is positive. Second terminal listed is
negative.









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3) Start and warm engine to operating temperature. Using scan
tool, read HO2S voltage. See HO2S ITEM LIST IDENTIFICATION table for
appropriate scan tool item number. While monitoring scan tool,
accelerate to 4000 RPM. Suddenly decelerate. Scan tool should read 0.2
volt or less. Suddenly accelerate. Scan tool should read 0.6-1.0 volt.
If voltage is not as specified, replace HO2S. If voltage is as
specified, go to next step.
HO2S ITEM LIST IDENTIFICATION TABLE









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Application Item No.
Montero - Federal
Front ......................................................... 11
Rear .......................................................... 59
Except Montero - Federal

connector. Install Test Harness (MB998464) between HO2S and HO2S
connector. Using DVOM, check resistance between specified HO2S
connector terminals. See
REAR HO2S HEATER CONNECTOR TERMINAL IDENTIFICATION table. HO2S
resistance should be 12 ohms at 68
F (20C). If resistance is not as
specified, replace HO2S. If resistance is as specified, go to step 3).
REAR HO2S HEATER CONNECTOR TERMINAL IDENTIFICATION TABLE









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Application Terminals No.
Montero ............................................ 1 & 3
3000GT ............................................. 2 & 4









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2) Raise and support drive wheels. Start and warm engine to
operating temperature. Place A/T in Low (M/T in 2nd). Using scan tool,\
read HO2S voltage (item 59 for right side or 69 for left side). While
monitoring scan tool, accelerate to 3500 RPM. Scan tool should read 0.
6-1.0 volt. If voltage is not as specified, replace HO2S. If voltage
is as specified, go to next step.
3) On 3000GT, go to next step. On Montero disconnect HO2S
connector and MFI relay connector. Using DVOM, check for continuity
between HO2S 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.
4) Using DVOM, check for open or short circuit between
specified HO2S connector terminal and PCM connector terminal(s). See
REAR HO2S-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION table. If open
or short circuit exists, repair wiring harness as necessary. If open
or short circuit does not exist, go to next step.
REAR HO2S-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION TABLE









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Application HO2S Terminal No. PCM Terminal No.
Montero - Federal ........ 3 ........................ 26
4 ........................ 73
All Others ............ ( 1) 3 ....................... 26
( 2) 3 ....................... 27
( 1) 4 ....................... 73
( 2) 4 ....................... 74
( 1) - Left rear HO2S.
( 2) - Right rear HO2S.









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5) Using DVOM, check for continuity between chassis ground
and specified HO2S connector terminal. See
REAR HO2S CONNECTOR GROUND CIRCUIT IDENTIFICATION table. If continuity
does not exist, repair wiring harness as necessary. If continuity
exists, go to next step.
REAR HO2S CONNECTOR GROUND CIRCUIT IDENTIFICATION TABLE









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Application Terminal No.
Montero & 3000GT ....................................... 2









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6) Condition required to set DTC is not present at this time.
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 P0170 & P0173: FUEL TRIM FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) Specific self-diagnostic test not available from
manufacturer at time of publication. Check volume airflow sensor, fuel
injectors, engine coolant temperature sensor, intake air temperature
sensor, barometric or manifold absolute pressure sensor, heated oxygen
sensor. See appropriate DTC test. Check related connectors and
harnesses. See L - WIRING DIAGRAMS article.
2) Also check fuel pressure, check for intake air leaks, and
for cracked manifold. See F - BASIC TESTING article.
DTC P0201-P0206: FUEL INJECTOR CIRCUIT FAILURE
NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For
circuit and wire color identification, see
L - WIRING DIAGRAMS article.
1) If using scan tool, go to step 3). Using a stethoscope or
long-bladed screwdriver, listen for clicking sound from each fuel
injector while engine is running or being cranked. If no sound is
heard from fuel injector(s), check fuel injector connections. Repair
connections as necessary. If connections are okay, go to next step.
2) Ensure engine coolant temperature is at 68
F (20C).
Disconnect fuel injector connector. Using DVOM, check resistance
between specified fuel injector terminals. See
FUEL INJECTOR TERMINAL IDENTIFICATION table. If resistance is not 2.0-
3.0 3000GT turbo or 13-16 ohms on all other models, replace fuel
injector(s). If resistance is as specified, go to step 6).
FUEL INJECTOR TERMINAL IDENTIFICATION TABLE









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Application Terminals No.
Montero ( 1) ........................................ 8 & 1
8 & 2
8 & 3
8 & 5
8 & 6
8 & 7
3000GT - Rear Bank ( 2)
Non-Turbo ........................................ 1 & 2
1 & 5
1 & 6
Turbo ............................................ 1 & 4
2 & 8
4 & 5
4 & 6
4 & 7
4 & 8
( 1) - Check resistance at intermediate fuel injector
connector (component side).
( 2) - Check resistance at rear fuel injector connector
(component side).









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3) Using scan tool, read FUEL INJECTOR DRIVE TIME (item 41)
while cranking engine. See INJECTOR CRANKING DRIVE TIME SPECIFICATIONS
table. Go to next step.
INJECTOR CRANKING DRIVE TIME SPECIFICATIONS TABLE









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Coolant Temperature Drive Time (ms)
32
F (0C)
Montero ...................................... 11.0-17.0
3000GT
DOHC
Non-Turbo ................................ 12.9-19.3
Turbo ..................................... 8.4-12.6
SOHC ....................................... 13.8-16.8
68
F (20C)
Montero ...................................... 28.0-42.0
3000GT
DOHC
Non-Turbo ................................ 36.1-54.1
Turbo .................................... 23.3-34.9
SOHC ....................................... 40.0-48.8
176
F (80C)
Montero ....................................... 7.4-11.2
3000GT
DOHC
Non-Turbo ................................. 8.2-12.4
Turbo ...................................... 5.4-8.2
SOHC ........................................ 8.6-10.6









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4) Ensure engine coolant temperature is at 176-205F (80-
95C), all accessories are off and A/T is in Park or M/T is in
Neutral. Using scan tool, read FUEL INJECTOR DRIVE TIME (item 41)
under specified engine conditions. See
INJECTOR OPERATING DRIVE TIME SPECIFICATIONS table. Go to next step.
INJECTOR OPERATING DRIVE TIME SPECIFICATIONS TABLE









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Engine Speed Drive Time (ms)
700 RPM
Montero ........................................ 2.1-3.3
3000GT
DOHC
Non-Turbo .................................. 2.5-3.7
Turbo ...................................... 1.7-2.9
SOHC ......................................... 2.3-3.5
2000-2500 RPM
Montero ........................................ 1.9-3.1
3000GT
DOHC
Non-Turbo .................................. 2.2-3.4
Turbo ...................................... 1.5-2.7
SOHC ......................................... 2.1-3.3
Suddenly Accelerated
Montero & 3000GT ................................... ( 1)
( 1) - Drive time should increase.









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5) Allow engine to idle after warm up. Using scan tool, shut
off fuel injectors in sequence. Idle should change when good fuel