sensor DAEWOO MATIZ 2003 Service Owner's Guide

1F–16 ENGINE CONTROLS
DAEWOO M-150 BL2
the obstruction of the reference air and degrade the O2S
performance.
Misfire Monitor Diagnostic Operation
The misfire monitor diagnostic is based on crankshaft
rotational velocity (reference period) variations. The En-
gine Control Module (ECM) determines crankshaft rota-
tional velocity using the Crankshaft Position (CKP)
sensor and the Camshaft Position (CMP) sensor. When
a cylinder misfires, the crankshaft slows down momen-
tarily. By monitoring the CKP and CMP sensor signals,
the ECM can calculate when a misfire occurs.
For a non-catalyst damaging misfire, the diagnostic will
be required to monitor a misfire present for between
1000–3200 engine revolutions.
For catalyst-damaging misfire, the diagnostic will re-
spond to misfire within 200 engine revolutions.
Rough roads may cause false misfire detection. A rough
road will cause torque to be applied to the drive wheels
and drive train. This torque can intermittently decrease
the crankshaft rotational velocity. This may be falsely
detected as a misfire.
A rough road sensor, or “G sensor,” works together with
the misfire detection system. The rough road sensor
produces a voltage that varies along with the intensity of
road vibrations. When the ECM detects a rough road,
the misfire detection system is temporarily disabled.
Misfire Counters
Whenever a cylinder misfires, the misfire diagnostic
counts the misfire and notes the crankshaft position at
the time the misfire occurred. These “misfire counters”
are basically a file on each engine cylinder. A current
and a history misfire counter are maintained for each
cylinder. The misfire current counters (Misfire Current
#1–4) indicate the number of firing events out of the last
200 cylinder firing events which were misfires. The mis-
fire current counter will display real time data without a
misfire DTC stored. The misfire history counters (Misfire
Histtory #1–4) indicate the total number of cylinder firing
events which were misfires. The misfire history counters
will display 0 until the misfire diagnostic has failed and a
DTC P0300 is set. Once the misfire DTC P0300 is set,
the misfire history counters will be updated every 200
cylinder firing events. A misfire counter is maintained for
each cylinder.
If the misfire diagnostic reports a failure, the diagnostic
executive reviews all of the misfire counters before re-
porting a DTC. This way, the diagnostic executive re-
ports the most current information.
When crankshaft rotation is erratic, a misfire condition
will be detected. Because of this erratic condition, the
data that is collected by the diagnostic can sometimes
incorrectly identify which cylinder is misfiring.
Use diagnostic equipment to monitor misfire counter
data on EOBD compliant vehicles. Knowing which spe-
cific cylinder(s) misfired can lead to the root cause, evenwhen dealing with a multiple cylinder misfire. Using the
information in the misfire counters, identify which cylin-
ders are misfiring. If the counters indicate cylinders
numbers 1 and 4 misfired, look for a circuit or compo-
nent common to both cylinders number 1 and 4.
The misfire diagnostic may indicate a fault due to a tem-
porary fault not necessarily caused by a vehicle emis-
sion system malfunction. Examples include the following
items:

Contaminated fuel.

Low fuel.

Fuel-fouled spark plugs.

Basic engine fault.
Fuel Trim System Monitor Diagnostic
Operation
This system monitors the averages of short-term and
long-term fuel trim values. If these fuel trim values stay
at their limits for a calibrated period of time, a malfunc-
tion is indicated. The fuel trim diagnostic compares the
averages of short-term fuel trim values and long-term
fuel trim values to rich and lean thresholds. If either val-
ue is within the thresholds, a pass is recorded. If both
values are outside their thresholds, a rich or lean DTC
will be recorded.
The fuel trim system diagnostic also conducts an intru-
sive test. This test determines if a rich condition is being
caused by excessive fuel vapor from the controlled char-
coal canister. In order to meet EOBD requirements, the
control module uses weighted fuel trim cells to deter-
mine the need to set a fuel trim DTC. A fuel trim DTC
can only be set if fuel trim counts in the weighted fuel
trim cells exceed specifications. This means that the ve-
hicle could have a fuel trim problem which is causing a
problem under certain conditions (i.e., engine idle high
due to a small vacuum leak or rough idle due to a large
vacuum leak) while it operates fine at other times. No
fuel trim DTC would set (although an engine idle speed
DTC or HO2S DTC may set). Use a scan tool to observe
fuel trim counts while the problem is occurring.
A fuel trim DTC may be triggered by a number of vehicle
faults. Make use of all information available (other DTCs
stored, rich or lean condition, etc.) when diagnosing a
fuel trim fault.
Fuel Trim Cell Diagnostic Weights
No fuel trim DTC will set regardless of the fuel trim
counts in cell 0 unless the fuel trim counts in the
weighted cells are also outside specifications. This
means that the vehicle could have a fuel trim problem
which is causing a problem under certain conditions (i.e.
engine idle high due to a small vacuum leak or rough
due to a large vacuum leak) while it operates fine at oth-
er times. No fuel trim DTC would set (although an en-
gine idle speed DTC or HO2S DTC may set). Use a
scan tool to observe fuel trim counts while the problem is
occurring.

ENGINE CONTROLS 1F–17
DAEWOO M-150 BL2
DIAGNOSTIC INFORMATION AND PROCEDURES
SYSTEM DIAGNOSIS
DIAGNOSTIC AIDS
If an intermittent problem is evident, follow the guide-
lines below.
Preliminary Checks
Before using this section you should have already per-
formed the “Euro On-Board Diagnostic (EOBD) System
Check.”
Perform a thorough visual inspection. This inspection
can often lead to correcting a problem without further
checks and can save valuable time. Inspect for the fol-
lowing conditions:

Engine Control Module (ECM) grounds for being
clean, tight, and in their proper location.

Vacuum hoses for splits, kinks, collapsing and proper
connections as shown on the Vehicle Emission Con-
trol Information label. Inspect thoroughly for any type
of leak or restriction.

Air leaks at the throttle body mounting area and the
intake manifold sealing surfaces.

Ignition wires for cracks, hardness, proper routing,
and carbon tracking.

Wiring for proper connections.

Wiring for pinches or cuts.
Diagnostic Trouble Code Tables
Do not use the Diagnostic Trouble Code (DTC) tables to
try and correct an intermittent fault. The fault must be
present to locate the problem.
Incorrect use of the DTC tables may result in the unnec-
essary replacement of parts.
Faulty Electrical Connections or Wiring
Most intermittent problems are caused by faulty electri-
cal connections or wiring. Perform a careful inspection
of suspect circuits for the following:

Poor mating of the connector halves.

Terminals not fully seated in the connector body.

Improperly formed or damaged terminals. All connec-
tor terminals in a problem circuit should be carefullyinspected, reformed, or replaced to insure contact
tension.

Poor terminal-to-wire connection. This requires re-
moving the terminal from the connector body.
Road Test
If a visual inspection does not find the cause of the prob-
lem, the vehicle can be driven with a voltmeter or a scan
tool connected to a suspected circuit. An abnormal volt-
age or scan tool reading will indicate that the problem is
in that circuit.
If there are no wiring or connector problems found and a
DTC was stored for a circuit having a sensor, except for
DTC P0171 and DTC P0172, replace the sensor.
Intermittent Malfunction Indicator Lamp
(MIL)
An intermittent Malfunction Indicator Lamp(MIL) with no
DTC present may be caused by the following:

Improper installation of electrical options such as
lights, two way radios, sound, or security systems.

MIL driver wire intermittently shorted to ground.
Fuel System
Some intermittent driveability problems can be attrib-
uted to poor fuel quality. If a vehicle is occasionally run-
ning rough, stalling, or otherwise performing badly, ask
the customer about the following fuel buying habits:

Do they always buy from the same source? If so, fuel
quality problems can usually be discounted.

Do they buy their fuel from whichever fuel station that
is advertising the lowest price? If so, check the fuel
tank for signs of debris, water, or other contamina-
tion.
IDLE LEARN PROCEDURE
Whenever the battery cables, the Engine Control Mod-
ule (ECM), or the fuse is disconnected or replaced, the
following idle learn procedure must be performed:
1. Turn the ignition ON for 10 seconds.
2. Turn the ignition OFF for 10 seconds.

ENGINE CONTROLS 1F–19
DAEWOO M-150 BL2
Euro On-Board Diagnostic (EOBD) System Check
StepActionValue(s)YesNo
1
1. Turn the ignition ON with the engine OFF.
2. Observe the Malfunction Indicator Lamp (MIL).
Is the MIL on?
–
Go to Step 2
Go to “No
Malfunction
Indicator
Lamp”
2
1. Turn the ignition OFF.
2. Install the scan tool.
3. Turn the ignition ON.
4. Attempt to display the Engine Control Module
(ECM) engine data with the scan tool.
Does the scan tool display the ECM engine data?
–
Go to Step 3Go to Step 8
3
1. Using the scan tool output test function, select the
MIL lamp control and command the MIL off.
2. Observe the MIL.
Does the MIL turn off?
–
Go to Step 4
Go to
“Malfunction
Indicator Lamp
on Steady”
4
Attempt to start the engine.
Does the engine start and continue to run?
–
Go to Step 5
Go to “Engine
Cranks But
Will Not Run”
5Select DISPLAY DTC with the scan tool.
Are any Diagnostic Trouble Codes stored?–Go to Step 6Go to Step 7
6
Check the display for DTCs P0107, P0108, P0113,
P0118, P0122, P0123, P0172, P1392.
Are two or more of the following DTCs stored?
–
Go to “Multiple
ECM
Information
Sensor DTCs
Set”
Go to
applicable DTC
table
7
Compare the ECM data values displayed on the
scan tool to the typical engine scan data values.
Are the displayed values normal or close to the
typical values?
–Go to “ECM
Output
Diagnosis”Go to indicated
component
system check
8
1. Turn the ignition OFF and disconnect the ECM.
2. Turn the ignition ON with the engine OFF.
3. Check the serial data circuit for an open, short to
ground, or short to voltage. Also check the Data
Link Connector (DLC) ignition feed circuit for an
open or short to ground, and check the DLC
ground circuits for an open.
Is a problem found?
–
Go to Step 9Go to Step 10
9
Repair the open, short to ground, or short to voltage
in the serial data circuit or the DLC ignition feed
circuit.
Is the repair complete?
–
System OK
–
10
1. Attempt to reprogram the ECM.
2. Attempt to display the ECM data with the scan
tool.
Does the scan tool display ECM engine data?
–
Go to Step 2Go to Step 11
11Replace the ECM.
Is the repair complete?–System OK–

ENGINE CONTROLS 1F–21
DAEWOO M-150 BL2
MULTIPLE ECM INFORMATION SENSOR DTCS SET
Circuit Description
The Engine Control Module (ECM) monitors various
sensors to determine engine operating conditions. The
ECM controls fuel delivery, spark advance, transaxle op-
eration, and emission control device operation based on
the sensor inputs.
The ECM provides a sensor ground to all of the sensors.
The ECM applies 5 volts through a pull-up resistor and
monitors the voltage present between the sensor and
the resistor to determine the status of the Engine Cool-
ant Temperature (ECT) sensor, the Intake Air Tempera-
ture (IAT) sensor. The ECM provides the Electric
Exhaust Gas Recirculation (EEGR) Pintle Position Sen-
sor, the Throttle Position (TP) sensor, the Manifold Ab-
solute Pressure (MAP) sensor, and the Fuel Tank
Pressure Sensor with a 5 volt reference and a sensor
ground signal. The ECM monitors the separate feed-
back signals from these sensors to determine their oper-
ating status.
Diagnostic Aids
Be sure to inspect the ECM and the engine grounds for
being secure and clean.
A short to voltage in one of the sensor circuits can cause
one or more of the following DTCs to be set: P0108,
P0113, P0118, P0123, P1106.If a sensor input circuit has been shorted to voltage, en-
sure that the sensor is not damaged. A damaged sensor
will continue to indicate a high or low voltage after the
affected circuit has been repaired. If the sensor has
been damaged, replace it.
An open in the sensor ground circuit between the ECM
and the splice will cause one or more of the following
DTCs to be set: P0108, P0113, P0118, P0123, P1106.
A short to ground in the 5 volt reference circuit or an
open in the 5 volt reference circuit between the ECM
and the splice will cause one or more of the following
DTCs to be set: P0107, P0112, P0117, P0122, P1107.
Check for the following conditions:

Inspect for a poor connection at the ECM. Inspect
harness connectors for backed-out terminals, im-
proper mating, broken locks, improperly formed or
damaged terminals, and poor terminal-to-wire con-
nection.

Inspect the wiring harness for damage. If the harness
appears to be OK, observe an affected sensor’s dis-
played value on the scan tool with the ignition ON and
the engine OFF while moving connectors and wiring
harnesses related to the affected sensors. A change
in the affected sensor’s displayed value will indicate
the location of the fault.

1F–22 ENGINE CONTROLS
DAEWOO M-150 BL2
Multiple ECM Information Sensor DTCs Set
StepActionValue(s)YesNo
1
Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the check complete.
–
Go to Step 2
Go to “Euro
On-Board
Diagnostic
System Check”
2
1. Turn the ignition OFF and disconnect the Engine
Control Module (ECM).
2. Turn the ignition ON and check the 5 volt
reference circuit for the following conditions:

Poor connection at the ECM.

Open between the ECM connector affected
sensors shorted to ground or voltage.
3. If a problem is found, locate and repair the open
or short circuit as necessary.
Is a problem found?
–
Go to Step 19Go to Step 3
3
1. Check the sensor ground circuit for the following
conditions:

Poor connection at the ECM or affected
sensors.

Open between the ECM connector and the
affected sensors.
2. If a problem is found, repair it as necessary.
Is a problem found?
–
Go to Step 19Go to Step 4
4
Measure the voltage of the Electric Exhaust Gas
Recirculation (EEGR) Pintle Position Sensor signal
circuit between ECM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 5Go to Step 9
5
Measure the voltage of the Manifold Absolute
Pressure (MAP) sensor signal circuit between the
ECM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 6Go to Step 11
6
Measure the voltage of the Throttle Position (TP)
sensor signal circuit between the ECM harness
connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 7Go to Step 12
7
Measure the voltage of the Intake Air Temperature
(IAT) sensor signal circuit between the ECM harness
connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 8Go to Step 13
8
Measure the voltage of the Engine Coolant
Temperature (ECT) sensor signal circuit between the
ECM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 16Go to Step 14
9
1. Disconnect the EEGR valve.
2. Measure the voltage of the EEGR Pintle Position
sensor signal circuit between the ECM harness
connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 10Go to Step 15
10Replace the EEGR valve.
Is the repair complete?–Go to Step 19–
11
Locate and repair the short to voltage in the MAP
sensor signal circuit.
Is the repair complete?
–
Go to Step 19
–

ENGINE CONTROLS 1F–23
DAEWOO M-150 BL2
Multiple ECM Information Sensor DTCs Set (Cont’d)
StepActionValue(s)YesNo
12
Locate and repair the short to voltage in the TP
sensor signal circuit.
Is the repair complete?
–
Go to Step 19
–
13
Locate and repair the short to voltage in the IAT
sensor signal circuit.
Is the repair complete?
–
Go to Step 19
–
14
Locate and repair the short to voltage in the ECT
sensor signal circuit.
Is the repair complete?
–
Go to Step 19
–
15
Locate and repair the short to voltage in the EEGR
Pintle Position sensor circuit.
Is the repair complete?
–
Go to Step 19
–
16
Measure the voltage of the Fuel Tank Pressure
sensor signal circuit between the ECM harness
connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 18Go to Step 17
17
Locate and repair the short to voltage in the Fuel
Tank Pressure sensor signal circuit.
Is the repair complete?
–
Go to Step 19
–
18Replace the ECM.
Is the repair complete?–Go to Step 19–
19
1. Using the scan tool, clear the Diagnostic Trouble
Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting the DTCs as specified in the supporting
text.
Does the scan tool indicate that this diagnostic ran
and passed?
–
Go to Step 20Go to Step 2
20
Check if any additional DTCs are set.
Are any DTCs displayed that have not been
diagnosed?
–
Go to
Applicable DTC
table
System OK

ENGINE CONTROLS 1F–25
DAEWOO M-150 BL2
ENGINE CRANKS BUT WILL NOT RUN
Caution: Use only electrically insulated pliers when
handling ignition wires with the engine running to
prevent an electrical shock.
Caution: Do not pinch or restrict nylon fuel lines.
Damage to the lines could cause a fuel leak, result-
ing in possible fire or personal injury.Important: If a no start condition exists, ensure the fuel
cutoff switch has not been tripped prior to further diagno-
sis.
Engine Cranks But Will Not Run
StepActionValue(s)YesNo
1
Perform an Euro On-Board Diagnostic (EOBD)
System Check.
Is the check complete.
–
Go to Step 2
Go to “Euro
On-Board
Diagnostic
System Check”
2Crank the engine.
Does the engine start and continue to run?–System OkGo to Step 3
3
Perform a cylinder compression test.
Is the cylinder compression for all of the cylinders at
or above the value specified?
1250 kPa
(181 psi)
Go to Step 7Go to Step 4
4Inspect the timing belt alignment.
Is the timing belt in alignment?–Go to Step 6Go to Step 5
5Align or replace the timing belt as needed.
Is the repair complete?–Go to Step 2–
6Repair internal engine damage as needed.
Is the repair complete?–Go to Step 2–
7Inspect the fuel pump fuse.
Is the problem found?–Go to Step 8Go to Step 9
8Replace the fuse.
Is the repair complete?–Go to Step 2–
9
Check for the presence of spark from all of the
ignition wires while cranking the engine.
Is spark present from all of the ignition wires?
–
Go to Step 23Go to Step 10
10
1. Measure the resistance of the ignition wires.
2. Replace any of the ignition wire(s) with a
resistance above the value specified.
3. Check for the presence of spark from all of the
ignition wire.
Is spark present from all of the ignition wires?
5 kΩGo to Step 2Go to Step 11
11
1. Turn the ignition OFF.
2. Disconnect the crankshaft position (CKP) sensor
connector.
3. Turn the ignition ON.
4. Measure the voltage between following terminals:

Terminal 1 and 3 of the CKP sensor connector.

Terminal 2 and 3 of the CKP sensor connector.

Terminal 1 of the CKP sensor connector and
ground.

Terminal 2 of the CKP sensor connector and
ground.
Are the voltage measure within the value specified?
≈ 0.4 VGo to Step 13Go to Step 12

1F–26 ENGINE CONTROLS
DAEWOO M-150 BL2
Engine Cranks But Will Not Run (Cont’d)
StepActionValue(s)YesNo
12
Check for an open or short in the wires between
CKP sensor connector and ECM connector and
repair as need.
Is the repair complete?
–
Go to Step 2
–
13
1. Disconnect electronic Ignition (EI) system ignition
coil connector to prevent the vehicle from starting.
2. Measure the voltage at ECM connector terminal
24 and 54 by backprobing the ECM connector.
Are the voltage readings near the value specified?
0.4 V with
ignition ON,
2.0 V during
cranking
Go to Step 15Go to Step 14
14Replace the CKP sensor.
Is the repair complete?–Go to Step 2–
15
1. Turn the ignition OFF.
2. Disconnect the electrical connector at EI system
ignition coil.
3. Connect a test light between terminal 1 of the EI
system ignition coil connector and ground.
4. Turn the ignition ON.
Is the test light on?
–
Go to Step 17Go to Step 16
16
Check for open in wire between the battery and EI
system ignition coil connector terminal 1 and repair
as needed.
Is the repair complete?
–
Go to Step 2
–
17
1. Turn the ignition OFF.
2. Disconnect ECM connector and EI system
ignition coil connector.
3. Measure the resistance between following
terminals:

Terminal 2 of ignition coil and terminal 1 of
ECM connector.

Terminal 3 of ignition coil and terminal 32 of
ECM connector.

Terminal 4 of ignition coil and terminal 31 of
ECM connector.
Are the resistance within the value specified?
0 ΩGo to Step 19Go to Step 18
18Check for open circuit and repair as needed.
Is the repair complete?–Go to Step 2–
19
1. Measure the resistance between following
terminals:

Terminal 1 and 2 of ignition coil.

Terminal 3 and 4 of ignition coil.
Are the resistance within the value specified?
2. Remove the high tension cable.
3. Measure the resistance between second coil.

Between 1 and 4

Between 2 and 3
Are the resistance within the value specified?
0.9Ω
5.3 kΩ
Go to Step 21Go to Step 20
20Replace the EI system ignition coil.
Is the repair complete?–Go to Step 2–

1F–34 ENGINE CONTROLS
DAEWOO M-150 BL2
FUEL SYSTEM DIAGNOSIS
Circuit Description
The fuel pump is an in-tank type mounted to a fuel send-
er assembly. The fuel pump will remain on as long as the
engine is cranking or running and the Engine Control
Module (ECM) is receiving reference pulses from the
crankshaft position (CKP) sensor. If there are no refer-
ence pulses, the ECM will turn off the fuel pump two sec-
onds after the ignition switch is turned ON or two
seconds after the engine stops running. The fuel pump
delivers fuel to the fuel rail and the fuel injectors, where
the fuel system pressure is controlled from 380 kPa (55
psi) by the fuel pressure regulator. The excess fuel is re-
turned to the fuel tank.
Caution: The fuel system is under pressure. To
avoid fuel spillage and the risk of personal injury orfire, it is necessary to relieve the fuel system pres-
sure before disconnecting the fuel lines.
Caution: Do not pinch or restrict nylon fuel lines.
Damage to the lines could cause a fuel leak, result-
ing in possible fire or personal injury.
Fuel Pressure Relief Procedure
1. Remove the fuel cap.
2. Remove the fuel pump fuse EF23 from the engine
fuse block.
3. Start the engine and allow the engine to stall.
4. Crank the engine for an additional 10 seconds.
Fuel System Pressure Test
Step Action Value(s) Yes No




1




1. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified and
holding steady?



380 kPa
(55 psi)



System OK



Go to Step 2




2




1. Relieve the fuel system pressure.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified but
not holding steady?


380 kPa
(55 psi)



Go to Step 13



Go to Step 3

3

Inspect the fuel lines for a leak.
Is the problem found?
–

Go to Step 4

Go to Step 5




4




1. Replace the fuel line(s) as needed.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified and
holding steady?


380 kPa
(55 psi)



System OK




–




5




1. Remove the fuel pump assembly.
2. With the fuel pump under pressure, inspect the
fuel pump coupling hoses for leaking.
Is the problem found?



–



Go to Step 6



Go to Step 7





6





1. Tighten or replace the fuel pump coupling hoses
as needed.
2. Install a fuel pressure gauge.
3. Turn the ignition ON.
Is the fuel pressure around the values specified and
holding steady?




380 kPa
(55 psi)




System OK




Go to Step 8

7


With the fuel system under pressure, inspect the fuel
return outlet for leaking.
Is the problem found?
–

Go to Step 8

Go to Step 9

ENGINE CONTROLS 1F–39
DAEWOO M-150 BL2
Main Relay Circuit Check
StepActionValue(s)YesNo
1
1. Turn the ignition OFF.
2. Disconnect the engine fuse block fuse EF26.
3. Turn the ignition ON.
4. With a test light connected to the ground, probe
the fuse terminals nearest the main relay for fuse
EF19.
Is the light on at both terminal?
–
System OKGo to Step 2
2Is the light on at only one terminal?–Go to Step 3Go to Step 4
3
Repair the open in the wiring between the main relay
connector terminal 30 and the fuse EF19 as needed.
Is the repair complete?
–
System OK
–
4
1. Turn the ignition OFF.
2. Remove the main relay.
3. Turn the ignition ON.
4. With a test light connected to the ground, probe
the main relay terminals 85 and 30.
Is the light on at both terminals.
–
Go to Step 8Go to Step 5
5
1. Turn the ignition OFF.
2. Check engine fuse block fuse EF19.
Is one or both fuse blown?
–
Go to Step 6Go to Step 7
6
1. Repair short circuit between terminal 87 of main
relay and heated oxygen sensor
2. Replace fuse EF19.
Is the repair complete?
–
System OK
–
7
Repair open circuit between terminal 30 of main
relay and fuse EF19.
Is the repair complete?
–
System OKGo to Step 8
8
1. Turn the ignition OFF.
2. Measure the resistance between following
terminals.

Terminal 86 of main relay and ground.

Terminal 87 of main relay and ground.
Is the resistance within the specified value
0 ΩGo to Step 10Go to Step 9
9Repair open circuit.
Is the repair complete?–System OK–
10Replace the main relay.
Is the repair complete?–System OK–