2) Disconnect pressure hose from oil pump. See Fig. 45.
Install Adapter (MB990993) on oil pump. Install Adapter (MB990994) o\
n
disconnected hose. Connect Pressure Gauge (MB990662) and shutoff valve\
between adapters. Open shutoff valve. Bleed steering hydraulic system.
See HYDRAULIC SYSTEM BLEEDING in STEERING SYSTEM article.
Fig. 45: Testing PSP Sensor Circuit
Courtesy of Mitsubishi Motor Sales of America
3) Install a thermometer in fluid reservoir. Start engine and
allow it to idle. Turn steering wheel several times until fluid
temperature reaches 122-140
F (50-60C). Disconnect PSP switch
connector. Install a DVOM between ground and PSP switch terminal. See
Fig. 45 . Note continuity reading on DVOM. Go to next step.
4) With engine idling, gradually close shutoff valve to
increase power steering system pressure. Check pressure when PSP
switch is actuated by watching for a change in continuity. PSP switch
HOW TO USE SYSTEM WIRING DIAGRAMS
1998 Mitsubishi Montero
GENERAL INFORMATION
Using Wiring Diagrams
All Models
INTRODUCTION
This cd obtains wiring diagrams and technical service
bulletins, containing wiring diagram changes from the domestic and
import manufacturers. These are checked for accuracy and are all
redrawn into a consistent format for easy use.
In the past, when cars were simpler, diagrams were simpler.
All components were connected by wires and diagrams seldom exceeded 4
pages in length. Today, some wiring diagrams require more than 16
pages. It would be impractical to expect a service technician to trace
a wire from page 1 across every page to page 16.
Removing some of the wiring maze reduces eyestrain and time
wasted searching across several pages. Today the majority of
these
diagrams follow a much improved format, which permits space for
internal switch details.
Wiring diagrams are drawn in a "top-down" format. The
diagrams are drawn with the power source at the top of the diagram and
the ground point at the bottom of the diagram. Components locations
are identified on the wiring diagrams. Any wires that don't connect
directly to a component are identified on the diagram to indicate
where they go.
COLOR ABBREVIATIONS
COLOR ABBREVIATIONS TABLE \
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Color Normal Optional
Black ................ BLK .......................... BK
Blue ................. BLU .......................... BU
Brown ................ BRN .......................... BN
Clear ................ CLR .......................... CR
Dark Blue .......... DK BLU ...................... DK BU
Dark Green ......... DK GRN ...................... DK GN
Green ................ GRN .......................... GN
Gray ................. GRY .......................... GY
Light Blue ......... LT BLU ...................... LT BU
Light Green ........ LT GRN ...................... LT GN
Orange ............... ORG .......................... OG
Pink ................. PNK .......................... PK
Purple ............... PPL .......................... PL
Red .................. RED .......................... RD
Tan .................. TAN .......................... TN
Violet ............... VIO .......................... VI
White ................ WHT .......................... WT
Yellow ............... YEL .......................... YL
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IDENTIFYING WIRING DIAGRAM ABBREVIATIONS
NOTE: Abbreviations used on these diagrams are normally
self-explanatory. If necessary see ABBREVIATIONS
allowing metal objects to contact the battery posts and the
vehicle at the same time.
CAUTION: Never disconnect the battery while the engine is running;
doing so could damage the car's electrical components.
REPLACING BLOWN FUSES
Before replacing a blown fuse, remove ignition key, turn off
all lights and accessories to avoid damaging the electrical system. Be
sure to use fuse with the correct indicated amperage rating. The use
of an incorrect amperage rating fuse may result in a dangerous
electrical system overload.
BRAKE PAD WEAR INDICATOR
Indicator will cause a squealing or scraping noise, warning
that brake pads need replacement.
BRAKE FLUID
WARNING: DO NOT use reclaimed fluid or fluid that has been stored
in old or open containers. It is essential that foreign
particles and other liquids are kept out of the brake fluid
reservoir.
CATALYTIC CONVERTER
Continued operation of vehicle with a severe malfunction
could cause converter to overheat, resulting in possible damage to
converter and vehicle.
ENGINE COOLANT SERVICE
WARNING: To avoid the danger of being scalded never change the coolant
when the engine is hot.
WARNING: Never remove the radiator cap when the engine is hot Serious
burns could be caused by high pressure fluid escaping from
the radiator.
CAUTION: When adding or replacing engine coolant, use a high quality
ethylene glycol antifreeze diluted with 50% distilled water.
When putting the cap on the reserve tank, line up the arrow
on the cap and the arrow on the tank, or coolant can leak out
ENGINE DRIVE BELT SERVICE
WARNING: Be sure the ignition key is OFF. The engine could rotate
unexpectedly.
ENGINE OIL
WARNING: The engine oil may be high enough to burn your fingers
when the drain plug is loosened. Wait until the drain plug
is cool enough to touch with you bare hands.
WARNING: Continuous contact with used engine oil has been found to
cause skin cancer in laboratory animals. Brief contact with
used engine oil may irritate skin. To minimize your exposure
to used oil, wear a long sleeve shirt and moisture-proof
gloves when changing oil. If oil contacts your skin, wash
problem symptoms. For model-specific Trouble Shooting,
refer to DIAGNOSTIC, or TESTING articles available in the
section(s) you are accessing.
BASIC HEATER SYSTEM TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE \
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Insufficient, Erratic,
or No Heat
Low Coolant Level
Incorrect thermostat.
Restricted coolant flow through
heater core.
Heater hoses plugged.
Misadjusted control cable.
Sticking heater control valve.
Vacuum hose leaking.
Vacuum hose blocked.
Vacuum motors inoperative.
Blocked air inlet.
Inoperative heater blower motor.
Oil residue on heater core fins.
Dirt on heater core fins. \
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Too Much Heat
Improperly adjusted cables.
Sticking heater control valve.
No vacuum to heater control valve.
Temperature door stuck open. \
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Air Flow Changes During
Acceleration
Vacuum system leak.
Bad check valve or reservoir. \
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Air From Defroster At All
Times
Vacuum system leak.
Improperly adjusted control cables.
Inoperative vacuum motor. \
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Blower Does Not Operate
Correctly
Blown fuse.
Blower motor windings open.
Resistors burned out.
Motor ground connection loose.
Wiring harness connections loose.
Blower motor switch inoperative.
Blower relay inoperative.
Fan binding or foreign object
in housing.
Fan blades broken or bent. \
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BRAKES
BRAKE SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
but it cannot figure out the throttling action. In other words, it
cannot distinguish the throttling from an open circuit (de-energized)
condition.
Yet current controlled injectors will still yield a
millisecond on-time reading on these DVOMs. You will find it is also
always the same, regardless of the operating conditions. This is
because it is only measuring the initial completely-closed circuit on-
time, which always takes the same amount of time (to lift the injector
pintle off its seat). So even though you get a reading, it is useless.
The second limitation is that a few erratic conditions can
cause inaccurate readings. This is because of a DVOM's slow display
rate; roughly two to five times a second. As we covered earlier,
measurements in between display updates get averaged. So conditions
like skipped injector pulses or intermittent long/short injector
pulses tend to get "averaged out", which will cause you to miss
important details.
The last limitation is that varying engine speeds can result
in inaccurate readings. This is caused by the quickly shifting
injector on-time as the engine load varies, or the RPM moves from a
state of acceleration to stabilization, or similar situations. It too
is caused by the averaging of all measurements in between DVOM display
periods. You can avoid this by checking on-time when there are no RPM
or load changes.
A lab scope allows you to overcome each one of these
limitations.
Checking Injector On-Time With Dwell Or Duty
If no tool is available to directly measure injector
millisecond on-time measurement, some techs use a simple DVOM dwell or
duty cycle functions as a replacement.
While this is an approach of last resort, it does provide
benefits. We will discuss the strengths and weaknesses in a moment,
but first we will look at how a duty cycle meter and dwell meter work.
How A Duty Cycle Meter and Dwell Meter Work
All readings are obtained by comparing how long something has
been OFF to how long it has been ON in a fixed time period. A dwell
meter and duty cycle meter actually come up with the same answers
using different scales. You can convert freely between them. See
RELATIONSHIP BETWEEN DWELL & DUTY CYCLE READINGS TABLE .
The DVOM display updates roughly one time a second, although
some DVOMs can be a little faster or slower. All measurements during
this update period are tallied inside the DVOM as ON time or OFF time,
and then the total ratio is displayed as either a percentage (duty
cycle) or degrees (dwell meter).
For example, let's say a DVOM had an update rate of exactly 1
second (1000 milliseconds). Let's also say that it has been
measuring/tallying an injector circuit that had been ON a total of 250
mS out of the 1000 mS. That is a ratio of one-quarter, which would be
displayed as 25% duty cycle or 15
dwell (six-cylinder scale). Note
that most duty cycle meters can reverse the readings by selecting the
positive or negative slope to trigger on. If this reading were
reversed, a duty cycle meter would display 75%.
Strengths of Dwell/Duty Meter
The obvious strength of a dwell/duty meter is that you can
compare injector on-time against a known-good reading. This is the
only practical way to use a dwell/duty meter, but requires you to have
known-good values to compare against.
Another strength is that you can roughly convert injector mS
on-time into dwell reading with some computations.
A final strength is that because the meter averages
everything together it does not miss anything (though this is also a
severe weakness that we will look at later). If an injector has a
fault where it occasionally skips a pulse, the meter registers it and
the reading changes accordingly.
Let's go back to figuring out dwell/duty readings by using
injector on-time specification. This is not generally practical, but
we will cover it for completeness. You NEED to know three things:
* Injector mS on-time specification.
* Engine RPM when specification is valid.
* How many times the injectors fire per crankshaft revolution.
The first two are self-explanatory. The last one may require
some research into whether it is a bank-fire type that injects every
360
of crankshaft rotation, a bank-fire that injects every 720 , or
an SFI that injects every 720 . Many manufacturers do not release this
data so you may have to figure it out yourself with a frequency meter.
Here are the four complete steps to convert millisecond on-
time:
1) Determine the injector pulse width and RPM it was obtained
at. Let's say the specification is for one millisecond of on-time at a
hot idle of 600 RPM.
2) Determine injector firing method for the complete 4 stroke
cycle. Let's say this is a 360
bank-fired, meaning an injector fires
each and every crankshaft revolution.
3) Determine how many times the injector will fire at the
specified engine speed (600 RPM) in a fixed time period. We will use
100 milliseconds because it is easy to use.
Six hundred crankshaft Revolutions Per Minute (RPM) divided
by 60 seconds equals 10 revolutions per second.
Multiplying 10 times .100 yields one; the crankshaft turns
one time in 100 milliseconds. With exactly one crankshaft rotation in
100 milliseconds, we know that the injector fires exactly one time.
4) Determine the ratio of injector on-time vs. off-time in
the fixed time period, then figure duty cycle and/or dwell. The
injector fires one time for a total of one millisecond in any given
100 millisecond period.
One hundred minus one equals 99. We have a 99% duty cycle. If
we wanted to know the dwell (on 6 cylinder scale), multiple 99% times
.6; this equals 59.4
dwell.
Weaknesses of Dwell/Duty Meter
The weaknesses are significant. First, there is no one-to-one
correspondence to actual mS on-time. No manufacturer releases
dwell/duty data, and it is time-consuming to convert the mS on-time
readings. Besides, there can be a large degree of error because the
conversion forces you to assume that the injector(s) are always firing\
at the same rate for the same period of time. This can be a dangerous
assumption.
Second, all level of detail is lost in the averaging process.
This is the primary weakness. You cannot see the details you need to
make a confident diagnosis.
Here is one example. Imagine a vehicle that has a faulty
injector driver that occasionally skips an injector pulse. Every
skipped pulse means that that cylinder does not fire, thus unburned O2
gets pushed into the exhaust and passes the O2 sensor. The O2 sensor
indicates lean, so the computer fattens up the mixture to compensate
for the supposed "lean" condition.
A connected dwell/duty meter would see the fattened pulse
width but would also see the skipped pulses. It would tally both and
likely come back with a reading that indicated the "pulse width" was
within specification because the rich mixture and missing pulses
offset each other.
This situation is not a far-fetched scenario. Some early GM