Nissan Rogue Service Manual: Circuit inspection
DESCRIPTION
OPEN |
A circuit is open when there is no continuity through a
section of the circuit. |
SHORT |
There are two types of shorts. |
|
When a circuit contacts another circuit and causes the normal
resistance to
change. |
|
When a circuit contacts a ground source and grounds the circuit. |
NOTE:
Refer to GI-38, "How to Check Terminal" to probe or check terminal.
TESTING FOR “OPENS” IN THE CIRCUIT
Before you begin to diagnose and test the system, you should rough sketch a
schematic of the system. This
will help you to logically walk through the diagnosis process. Drawing the
sketch will also reinforce your working
knowledge of the system.
Continuity Check Method
The continuity check is used to find an open in the circuit. The digital
multimeter (DMM) set on the resistance
function will indicate an open circuit as over limit (no beep tone or no ohms
symbol). Make sure to always start
with the DMM at the highest resistance level.
To help in understanding the diagnosis of open circuits, please refer to the
previous schematic.
- Disconnect the battery negative cable.
- Start at one end of the circuit and work your way to the other
end. (At the fuse block in this example)
- Connect one probe of the DMM to the fuse block terminal on the
load side.
- Connect the other probe to the fuse block (power) side of SW1.
Little or no resistance will indicate that portion
of the circuit has good continuity. If there were an open in the circuit,
the DMM would indicate an over
limit or infinite resistance condition. (point A)
- Connect the probes between SW1 and the relay. Little or no
resistance will indicate that portion of the circuit
has good continuity. If there were an open in the circuit, the DMM would
indicate an over limit or infinite resistance
condition. (point B)
- Connect the probes between the relay and the solenoid. Little or
no resistance will indicate that portion of the
circuit has good continuity. If there were an open in the circuit, the DMM
would indicate an over limit or infinite
resistance condition. (point C)
Any circuit can be diagnosed using the approach in the previous example.
Voltage Check Method
To help in understanding the diagnosis of open circuits please refer to the
previous schematic.
In any powered circuit, an open can be found by methodically checking the system
for the presence of voltage.
This is done by switching the DMM to the voltage function.
- Connect one probe of the DMM to a known good ground.
- Begin probing at one end of the circuit and work your way to the
other end.
- With SW1 open, probe at SW1 to check for voltage.
Voltage; open is further down the circuit than SW1. no voltage; open is
between fuse block and SW1 (point A).
- Close SW1 and probe at relay.
Voltage; open is further down the circuit than the relay.
No voltage; open is between SW1 and relay (point B).
- Close the relay and probe at the solenoid.
Voltage; open is further down the circuit than the solenoid.
No voltage; open is between relay and solenoid (point C).
Any powered circuit can be diagnosed using the approach in the previous
example.
TESTING FOR “SHORTS” IN THE CIRCUIT
To simplify the discussion of shorts in the system, please refer to the
following schematic.
Resistance Check Method
- Disconnect the battery negative cable and remove the blown fuse.
- Disconnect all loads (SW1 open, relay disconnected and solenoid
disconnected) powered through the fuse.
- Connect one probe of the DMM to the load side of the fuse
terminal. Connect the other probe to a known
good ground.
- With SW1 open, check for continuity.
Continuity; short is between fuse terminal and SW1 (point A).
No continuity; short is further down the circuit than SW1.
- Close SW1 and disconnect the relay. Put probes at the load side of
fuse terminal and a known good ground.
Then, check for continuity.
Continuity; short is between SW1 and the relay (point B).
No continuity; short is further down the circuit than the relay.
- Close SW1 and jump the relay contacts with jumper wire. Put probes
at the load side of fuse terminal and a
known good ground. Then, check for continuity.
Continuity; short is between relay and solenoid (point C).
No continuity; check solenoid, retrace steps.
Voltage Check Method
- Remove the blown fuse and disconnect all loads (i.e. SW1 open,
relay disconnected and solenoid disconnected)
powered through the fuse.
- Turn the ignition key to the ON or START position. Verify battery
voltage at the battery + side of the fuse terminal
(one lead on the battery + terminal side of the fuse block and one lead on a
known good ground).
- With SW1 open and the DMM leads across both fuse terminals, check
for voltage.
Voltage; short is between fuse block and SW1 (point A).
No voltage; short is further down the circuit than SW1.
- With SW1 closed, relay and solenoid disconnected and the DMM leads
across both fuse terminals, check for
voltage.
Voltage; short is between SW1 and the relay (point B).
No voltage; short is further down the circuit than the relay.
- With SW1 closed, relay contacts jumped with fused jumper wire
check for voltage.
Voltage; short is down the circuit of the relay or between the relay and the
disconnected solenoid (point C).
No voltage; retrace steps and check power to fuse block.
GROUND INSPECTION
- Remove the ground bolt or screw.
- Inspect all mating surfaces for tarnish, dirt, rust, etc.
- Clean as required to assure good contact.
- Reinstall bolt or screw securely.
- Inspect for “add-on” accessories which may be interfering with the
ground circuit.
- If several wires are crimped into one ground eyelet terminal,
check for proper crimps. Make sure all of the
wires are clean, securely fastened and providing a good ground path. If
multiple wires are cased in one eyelet
make sure no ground wires have excess wire insulation.
VOLTAGE DROP TESTS
- Voltage drop tests are often used to find components or circuits
which have excessive resistance. A voltage
drop in a circuit is caused by a resistance when the circuit is in
operation.
- Check the wire in the illustration. When measuring resistance with
DMM, contact by a single strand of wire
will give reading of 0 ohms. This would indicate a good circuit. When the
circuit operates, this single strand
of wire is not able to carry the current. The single strand will have a high
resistance to the current. This will
be picked up as a slight voltage drop.
- Unwanted resistance can be caused by many situations as follows:
- Undersized wiring (single strand example)
- Corrosion on switch contacts
- Loose wire connections or splices.
- If repairs are needed always use wire that is of the same or
larger gauge.
Measuring Voltage Drop — Accumulated Method
- Connect the DMM across the connector or part of the circuit you
want to check. The positive lead of the
DMM should be closer to power and the negative lead closer to ground.
- Operate the circuit.
- The DMM will indicate how many volts are being used to “push”
current through that part of the circuit.
Note in the illustration that there is an excessive 4.1 volt drop between
the battery and the bulb.
Measuring Voltage Drop — Step-by-Step
- The step-by-step method is most useful for isolating excessive
drops in low voltage systems (such as those
in “Computer Controlled Systems”).
- Circuits in the “Computer Controlled System” operate on very low
amperage.
- The (Computer Controlled) system operations can be adversely
affected by any variation in resistance in the
system. Such resistance variation may be caused by poor connection, improper
installation, improper wire
gauge or corrosion.
- The step by step voltage drop test can identify a component or
wire with too much resistance.
CONTROL UNIT CIRCUIT TEST
System Description
- When the switch is ON, the control unit lights up the lamp.
CASE 1
INPUT-OUTPUT VOLTAGE CHART
- The voltage value is based on the body ground.
- *: If high resistance exists in the switch side circuit (caused by
a single strand), terminal 1 does not detect battery voltage. Control unit
does not detect the switch is ON even if the switch does not turn ON.
Therefore, the control unit does not supply power to light up the
lamp.
CASE 2
INPUT-OUTPUT VOLTAGE CHART
- The voltage value is based on the body ground.
- *: If high resistance exists in the switch side circuit (caused by
a single strand), terminal 2 does not detect approx. 0V. Control unit
does not detect the switch is ON even if the switch does not turn ON.
Therefore, the control unit does not control ground to light up the
lamp.
DESCRIPTION
Sometimes the symptom is not present when the vehicle is brought in for
service. If possible, re-create the
conditions present at the time of the incident. Doing so may help avoid a No ...
Description
NOTE:
This vehicle is diagnosed using the CONSULT-III plus.
When CONSULT is connected with a data link connector equipped
on the vehicle side, it will communicate with the co ...
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Basic inspection
DIAGNOSIS AND REPAIR WORK FLOW
Work Flow
DETAILED FLOW
1.INTERVIEW FROM THE CUSTOMER
Clarify customer complaints before inspection. First of all, perform an
interview utilizing DLN-32, "Diagnostic
Work Sheet" and reproduce symptoms as well as fully understand it. Ask customer
abou ...
P0605 ECM
DTC Description
DTC DETECTION LOGIC
DTC No.
CONSULT screen terms
(Trouble diagnosis content)
DTC detecting condition
P0605
ECM
[Internal control module read only memory
(ROM) error]
Malfunction in the internal ROM of ECM.
POSSIBLE CAUSE
ECM
FAIL-SAFE
T ...
Precaution
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT
BELT
PRE-TENSIONER"
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT
PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the
...
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