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
wiring harness as necessary. If continuity exists, go to next step.
5) Reconnect PCM connector. Turn ignition switch to ON
position. Check voltage between chassis ground and ECT sensor
connector terminal No. 1. If voltage is not 4.5-4.9 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 P0120: THROTTLE POSITION (TP) SENSOR 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 TP sensor
connector. Using DVOM, check resistance between TP sensor terminals
No. 1 and No. 4. If resistance is not 3500-6500 ohms, replace TP
sensor. If resistance is as specified, go to next step.
2) Check resistance between TP sensor terminals No. 1 and 3
on Montero or No. 2 and 4 on 3000GT. While monitoring DVOM, slowly
open throttle from idle to fully open position. If resistance does not
change smoothly, replace TP sensor. If resistance changes smoothly, go
to step 4).
3) Turn ignition switch to ON position. Using scan tool, read
TP sensor voltage value (item 14). With throttle at idle, value should\
read 300-1000 mV. Value should increase while slowly opening throttle.
At wide open throttle, value should read 4500-5500 mV. If value is not
as specified, replace TP sensor. If value is as specified, go to next
step.
4) Disconnect TP sensor connector. Using DVOM, check
continuity between chassis ground and TP sensor connector terminal No.
1. If continuity does not exist, repair wiring harness as necessary.
If continuity exists on 3000GT, go to next step. On Montero, go to
step 6).
5) Check continuity between chassis ground and TP sensor
connector terminal No. 4. If continuity does not exist, repair wiring
harness as necessary. If continuity exists, go to next step.
6) Turn ignition switch to OFF position. Disconnect PCM
connector. Ground specified PCM connector terminal. See
TP SENSOR-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION table. Check
for continuity between chassis ground and specified TP sensor
connector terminal. If continuity does not exist, repair wiring
harness as necessary. If continuity exists on 3000GT, go to step 8).
On Montero, go to next step.
TP SENSOR-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION TABLE
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Application TP Sensor Terminal No. PCM Terminal No.
Montero ................. 3 ......................... 78
4 ......................... 42
3000GT .................. 2 ......................... 78
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7) Reconnect PCM connector. Turn ignition switch to ON
position. Check voltage between chassis ground and TP sensor connector
terminal No. 4 on Montero or No. 1 on 3000GT. 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.
8) 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 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
Front
Left ........................................................ 39
Right ....................................................... 11
Rear
Left ........................................................ 69
Right ....................................................... 59
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4) While monitoring scan tool, accelerate to 2500 RPM and
decelerate to 700 RPM (idle). Scan tool should switch from 0.6-1.0
volt to 0.4 volt or less. If voltage is not as specified, replace
HO2S. If voltage is as specified, go to next step.
5) 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 step 7).
6) Disconnect HO2S connector. Turn ignition switch to ON
position. Using DVOM, check voltage between chassis ground and HO2S
connector terminal No. 1. If battery voltage does not exists, repair
wiring harness as necessary. If battery voltage exists, go to next
step.
7) Turn ignition switch to OFF position. With HO2S connector
disconnected, disconnect PCM connector. Using DVOM, check for open or
short circuit between specified HO2S connector terminal and PCM
connector terminal. See
FRONT HO2S-TO-PCM 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.
FRONT HO2S-TO-PCM HARNESS TERMINAL IDENTIFICATION TABLE
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Application HO2S Terminal No. PCM Terminal No.
Montero - Federal .......... 3 ....................... 3
4 ...................... 71
All Others .............. ( 1) 3 ...................... 3
( 2) 3 ...................... 4
( 1) 4 ..................... 71
( 2) 4 ..................... 72
( 1) - Left front HO2S.
( 2) - Right front HO2S.
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8) Using DVOM, check for continuity between chassis ground
and HO2S connector terminal No. 2. If continuity does not exist,
repair wiring harness as necessary. If continuity exists, go to next
step.
9) 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 P0136, P0141, P0156 & P0161: REAR 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 next step. Disconnect rear HO2S
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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