AGI070
HARNESS INDICATIONNJGI0003S0202+Letter designations next to test meter probe indicate harness
(connector) wire color.
+Connector numbers in a single circle M33 indicate harness
connectors.
COMPONENT INDICATIONNJGI0003S0203+Connector numbers in a double circle F211 indicate compo-
nent connectors.
SGI860
SWITCH POSITIONSNJGI0003S0204Switches are shown in wiring diagrams as if the vehicle is in the
ªnormalº condition.
A vehicle is in the ªnormalº condition when:
+ignition switch is ªOFFº,
+doors, hood and trunk lid/back door are closed,
+pedals are not depressed, and
+parking brake is released.
DETECTABLE LINES AND NON-DETECTABLE LINESNJGI0003S0205In some wiring diagrams, two kinds of lines, representing wires,
with different weight are used.
+A line with regular weight (wider line) represents a ªdetectable
line for DTC (Diagnostic Trouble Code)º. A ªdetectable line for
DTCº is a circuit in which ECM can detect its malfunctions with
the on board diagnostic system.
+A line with less weight (thinner line) represents a ªnon-detect-
able line for DTCº. A ªnon-detectable line for DTCº is a circuit
in which ECM cannot detect its malfunctions with the on board
diagnostic system.
HOW TO READ WIRING DIAGRAMS
Description (Cont'd)
GI-17
NJGI0005
Work FlowNJGI0005S01
SGI838
STEP DESCRIPTION
STEP 1 Get detailed information about the conditions and the environment when the incident occurred.
The following are key pieces of information required to make a good analysis:
WHATVehicle Model, Engine, Transmission and the System (i.e. Radio).
WHENDate, Time of Day, Weather Conditions, Frequency.
WHERERoad Conditions, Altitude and Traffic Situation.
HOWSystem Symptoms, Operating Conditions (Other Components Interaction).
Service History and if any After Market Accessories have been installed.
STEP 2 Operate the system, road test if necessary.
Verify the parameter of the incident.
If the problem can not be duplicated, refer to ªIncident Simulation Testsº next page.
STEP 3 Get the proper diagnoses materials together including:
POWER SUPPLY ROUTING
System Operation Descriptions
Applicable Service Manual Sections
Check for any Service Bulletin.
Identify where to begin diagnoses based upon your knowledge of the system operation and the cus-
tomer comments.
STEP 4 Inspect the system for mechanical binding, loose connectors or wiring damage.
Determine which circuits and components are involved and diagnose using the Power Supply Routing
and Harness Layouts.
STEP 5 Repair or replace the incident circuit or component.
STEP 6 Operate the system in all modes. Verify the system works properly under all conditions. Make sure you
have not inadvertently created a new incident during your diagnoses or repair steps.
HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Work Flow
GI-21
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 Ð Accumulated Method
1) Connect the voltmeter across the connector or part of the cir-
cuit you want to check. The positive lead of the voltmeter
should be closer to power and the negative lead closer to
ground.
2) Operate the circuit.
3) The voltmeter will indicate how many volts are being used to
ªpushº 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.
SGI974
Measuring Voltage Drop Ð Step by Step
The step by step method is most useful for isolating excessive
drops in low voltage systems (such as those in ªComputer Con-
trolled Systemsº).
Circuits in the ªComputer Controlled Systemº operate on very low
amperage.
The (Computer Controlled) system operations can be adversely
affected by any variation in resistance in the system. Such resis-
tance 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.
HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-28
21 CHECK HEATED OXYGEN SENSOR 1 (FRONT) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
6. Running engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.), check that the
monitor fluctuates between ªLEANº and ªRICHº more than 5 times during 10 seconds.
1 time: RICH®LEAN®RICH
2 times: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 62 and ground.
6. Make sure that the voltage fluctuates between 0 to 0.3V and 0.6 to 1.0V more than 5 times during 10 seconds at 2,000
rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©INSPECTION END
NG©GO TO 22.
22 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator. Refer to EC-39.
2. Check mass air flow sensor and its circuit. Refer to EC-152.
3. Check injector and its circuit. Refer to EC-446.
Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit. Refer to EC-163.
5. Check ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 3.
23 CHECK HEATED OXYGEN SENSOR 1 (FRONT) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) harness connector.
4. Check harness continuity between ECM terminal 62 and heated oxygen sensor 1 (front) harness connector terminal 1.
Refer to Wiring Diagram, EC-176.
Continuity should exist.
OK or NG
OK©GO TO 25.
NG©GO TO 24.
24 REPAIR OR REPLACE
Repair or replace harness between ECM and heated oxygen sensor 1 (front).
©GO TO 3.
BASIC SERVICE PROCEDUREQG
Inspection Procedure (Cont'd)
EC-51
Diagnostic ProcedureNJEC0278
1 CHECK INPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector and combination meter harness connector.
3. Check harness continuity between ECM terminal 86 and meter terminal 4.
Refer to wiring diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors M63, F102
+Harness for open or short between ECM and combination meter
©Repair open circuit or short to ground or short to power in harness or connectors.
3 CHECK SPEEDOMETER FUNCTION
Make sure that speedometer functions properly.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 CHECK SPEEDOMETER CIRCUIT
Check the following.
+Harness connectors M63, F102
+Harness connectors M169, F113
+Harness for open or short between combination meter and vehicle speed sensor
OK©Check combination meter and vehicle speed sensor. Refer to EL-89, ªMETERS AND
GAUGESº.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-144.
©INSPECTION END
DTC P0500 VEHICLE SPEED SENSOR (VSS)QG
Diagnostic Procedure
EC-312
Diagnostic ProcedureNJEC0659
1 CHECK VEHICLE SPEED SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector and combination meter harness connector.
3. Check harness continuity between ECM terminal 417 and combination meter terminal 4. Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors M63, F102
+Harness for open or short between ECM and combination meter
©Repair open circuit or short to ground or short to power in harness or connectors.
3 CHECK SPEEDOMETER FUNCTION
Make sure that speedometer functions properly.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 CHECK SPEEDOMETER CIRCUIT FOR OPEN AND SHORT
Check the following.
+Harness connectors M63, F102
+Harness for open or short between vehicle speed sensor and engine ground
+Harness for open or short between combination meter and vehicle speed sensor
OK or NG
OK©Check vehicle speed sensor and combination meter. Refer to EL section.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-559.
©INSPECTION END
DTC P0500 VEHICLE SPEED SENYD
Diagnostic Procedure
EC-596
6 CHECK GLOW INDICATOR LAMP POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect combination meter harness connector M32 or M152 or M171.
3. Turn ignition switch ªONº.
4. Check voltage between combination meter terminal 40 or 17 or 1 and ground with CONSULT-II or tester.
YEC060A
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
1. Fuse block (J/B) connector M1
2. 10A fuse
3. Harness for open or short between combination meter and fuse
©Repair open circuit or short to ground or short to power in harness or connectors.
8 CHECK GLOW INDICATOR LAMP OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Disconnect combination meter harness connector M171.
4. Check harness continuity between ECM terminal 508 and combination meter terminal 17. Refer to Wiring Diagram.
Continuity should exist.
5. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 10.
NG©GO TO 9.
9 DETECT MALFUNCTIONING PART
Check the following.
1. Harness connectors M63, F102
2. Harness for open or short between combination meter and ECM
©Repair open circuit or short to ground or short to power in harness or connectors.
10 CHECK COMBINATION METER
Check combination meter and glow indicator lamp. Refer to EL-89, ªMeter and Gaugesº.
OK or NG
OK©GO TO 18.
NG©Repair or replace combination meter or glow indicator lamp.
GLOW CONTROL SYSTEMYD
Diagnostic Procedure (Cont'd)
EC-682
2 CHECK TCM GROUND CIRCUIT
1. Turn ignition switch to ªOFFº position.
2. Disconnect TCM harness connector.
3. Check continuity between TCM terminals 25, 48 and ground.
SAT468J
Continuity should exist.
If OK, check harness for short to ground and short to power.
OK or NG
OK©GO TO 3.
NG©Repair open circuit or short to ground or short to power in harness or connectors. Refer
to ªWiring Diagram Ð AT Ð MAINº, AT-121.
3 CHECK LAMP CIRCUIT
1. Turn ignition switch to ªOFFº position.
2. Check resistance between TCM terminals 13 and 10.
Resistance: 50 - 100W
SAT469JB
3. Reinstall any part removed.
OK or NG
OK©GO TO 4.
NG©Check the following items:
+O/D OFF indicator lamp.
Refer to EL-89, ªMETERS AND GAUGESº.
+Harness and fuse for short or open between ignition switch and O/D OFF indicator
lamp (Main harness)
Refer to EL-10, ªPOWER SUPPLY ROUTINGº.
+Harness for short or open between O/D OFF indicator lamp and TCM.
TROUBLE DIAGNOSES FOR SYMPTOMS
1. O/D OFF Indicator Lamp Does Not Come On (Cont'd)
AT-289