air flow meter SUZUKI GRAND VITARA 2001 2.G Owners Manual

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-13
STEP 2. DIAGNOSTIC TROUBLE CODE (DTC)/FREEZE FRAME DATA CHECK
First, check DTC, referring to “DIAGNOSTIC TROUBLE CODE CHECK” in this section. If DTC is indicated,
record DTC and freeze frame data.
After that clear DTC referring to “DIAGNOSTIC TROUBLE CODE CLEARANCE” in this section. DTC indicates
malfunction that occurred in the system but does not indicate whether it exists now or it occurred in the past and
the normal condition has been restored now. To check which case applies, check the symptom in question
according to Step 5 and recheck DTC according to Step 6, 7.
Attempt to diagnose a trouble based on DTC in this step only or failure to clear the DTC (including pending DTC)
in this step will lead to incorrect diagnosis, trouble diagnosis of a normal circuit or difficulty in troubleshooting.
STEP 3. and 4. VISUAL INSPECTION
Be sure to perform visual check of the following items that support proper function of the engine.
STEP 5. TROUBLE SYMPTOM CONFIRMATION
Based on information obtained in Step 1 “CUSTOMER COMPLAINT ANALYSIS” and Step 2 “DTC/FREEZE
FRAME DATA CHECK”, confirm trouble symptoms. Also, reconfirm DTC according to “DTC CONFIRMATION
PROCEDURE” described in each “DTC FLOW TABLE”.NOTE:
For A/T vehicle, if only DTC P0705, P0715, P0720, P0741, P0743, P0751, P0753, P0756, P0758, or P1875
is indicated in this step, proceed to “DIAGNOSIS” in SECTION 7B1.
INSPECTION ITEM REFERRING SECTION
• Engine oil - - - - - level, leakage
• Engine coolant - - - - - level, leakage
• Fuel - - - - - level, leakage
• A/T fluid - - - - - level, leakage
• Air cleaner element - - - - - dirt, clogging
• Battery - - - - - fluid level, corrosion of terminal
• Water pump belt and/or cooling fan belt - - - - - tension, damage
• Accelerator cable - - - - - play, installation
• A/T throttle cable - - - - - play, installation
• Vacuum hoses of air intake system
- - - - - disconnection, looseness, deterioration, bend
• Connectors of electric wire harness - - - - - disconnection, friction
• Fuses - - - - - burning
• Parts - - - - - installation, bolt - - - - - looseness
• Parts - - - - - deformation
• Other parts that can be checked visually
• Also check following items at engine start, if possible
– Malfunction indicator lamp - - - - - operation
– Charge warning lamp - - - - - operation
– Engine oil pressure warning lamp - - - - - operation
– Engine coolant temp. meter - - - - - operation
– Fuel lever meter - - - - - operation
– Abnormal air being inhaled from air intake system
– Exhaust system - - - - - leakage of exhaust gas, noise
– Other parts that can be checked visuallySECTION 0B
SECTION 0B
SECTION 0B
SECTION 0B
SECTION 0B
SECTION 0B
SECTION 6C
SECTION 6E2
SECTION 6E2
SECTION 6A2
SECTION 8
SECTION 6-1
SECTION 6H
SECTION 8/6A2
SECTION 8
SECTION 8

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-27
Scan tool data definitions
COOLANT TEMP (Engine Coolant Temp., °C/°F)
It is detected by engine coolant temp. sensor.
INTAKE AIR TEMP (°C/°F)
It is detected by intake air temp. sensor.
DESIRE IDLE (Desired Idle Speed RPM)
The desired idle speed is an ECM (PCM) internal parameter which indicates the ECM (PCM) requested idle. If
the engine is not running, the number is not valid.
CLOSED THROT POS (Closed Throttle Position ON/OFF)
This parameter will read ON when the throttle valve is fully closed. Or OFF when the throttle is not fully closed.
IAC FLOW DUTY (%)
This parameter indicates IAC valve opening rate which controls bypass air flow.
ENGINE SPEED (RPM)
It is computed by reference pulses from the Camshaft Position Sensor.
SHORT FT B1 (Short Term Fuel Trim Bank 1, %) / SHORT FT B2 (Short Term Fuel Trim Bank 2, %)
Short term fuel trim value represents short term corrections to the air/fuel mixture computation. A value of 0 indi-
cates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies an
enleanment correction.
LONG FT B1 (Long Term Fuel Trim Bank 1, %) / LONG FT B2 (Long Term Fuel Trim Bank 2, %)
Long term fuel trim value represents long term corrections to the air/fuel mixture computation. A value of 0 indi-
cates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies an
enleanment correction.
IGNITION ADVANCE (Ignition Timing Advance For No.1 Cylinder, °)
Ignition timing of No.1 cylinder is commanded by ECM (PCM). The actual ignition timing should be checked by
using the timing light.
BATTERY VOLTAGE (V)
This parameter indicates battery positive voltage inputted from main relay to ECM (PCM).
MAF (Mass Air Flow Rate, g/s, lb/min)
It represents total mass of air entering intake manifold which is measured by mass air flow sensor.
INJ PULSE WIDTH B1 (Fuel Injection Pulse Width Bank 1, msec) / INJ PULSE WIDTH B2 (Fuel Injec-
tion Pulse Width Bank 2, msec)
This parameter indicates time of the injector drive (valve opening) pulse which is output from ECM (PCM).
THROTTLE POS (Absolute Throttle Position, %)
When throttle position sensor is fully closed position, throttle opening is indicated as 0 % and 100 % for full open
position.

6-1-28 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
TP SENSOR VOLT (TP Sensor Output Voltage, V)
Throttle Position Sensor reading provides throttle valve opening information in the from of voltage.
O2S B1 S1 (HO2S Bank 1 Sensor 1 Output Voltage, V) / O2S B2 S1 (HO2S Bank 2 Sensor 1 Output
Voltage, V)
It indicates output voltage of HO2S SENSOR 1 installed on exhaust manifold (pre-catalyst).
O2S B1 S2 (HO2S Bank 1 Sensor 2 Output Voltage, V) / O2S B2 S2 (HO2S Bank 2 Sensor 2 Output
Voltage, V)
If indicates output voltage of HO2S SENSOR 2 installed on exhaust pipe (post-catalyst). It is used to detect cat-
alyst deterioration.
FUEL SYSTEM B1 (Fuel System Bank 1 Status) / Fuel System B2 (Fuel System Bank 2 Status)
Air/fuel ratio feedback loop status displayed as one of the followings.
OPEN : Open loop-has not yet satisfied conditions to go closed loop.
CLOSED : Closed loop-using oxygen sensor(s) as feedback for fuel control.
OPEN-DRIVE COND : Open loop due to driving conditions (Power enrichment, etc.).
OPEN SYS FAULT : Open loop due to detected system fault.
CLOSED-ONE O2S : Closed loop, but fault with at least one oxygen sensor may be using single oxygen sensor
for fuel control.
CALC LOAD (Calculated Load Value, %)
Engine load displayed as a percentage of maximum possible load. Value is calculated mathematically using the
formula : actual (current) intake air volume ÷ maximum possible intake air volume x 100%.
TOTAL FUEL TRIM (%)
The value of total fuel trim is obtained by putting values of short term fuel trim and long term fuel trim together.
This value indicates how much correction is necessary to keep the air/fuel mixture stoichiometrical.
CANIST PRG DUTY (EVAP Canister Purge Flow Duty, %)
This parameter indicates valve ON (valve open) time rate within a certain set cycle of EVAP canister purge valve
which controls the amount of EVAP purge.
VEHICLE SPEED (km/h, MPH)
It is computed based on pulse signals from vehicle speed sensor on transfer or transmission.
FUEL CUT (ON/OFF)
ON : Fuel being cut (output signal to injector is stopped).
OFF : Fuel not being cut.
MAP (Manifold Absolute Pressure, mmHg, kPa)
This parameter indicates the pressure in the intake manifold absolute pressure.
A/C CONDENSER FAN (ON/OFF)
This parameter indicates the state of the A/C Condenser Fan control signal.
BLOWER FAN (ON/OFF)
This parameter indicates the state of the blower fan motor switch.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-59
DTC CONFIRMATION PROCEDURE
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and start
engine.
3) Increase vehicle speed to 55 km/h (35 mph) or more.
4) Keep driving above vehicle speed for 2 min. or more (Change of vehicle speed is permitted in this step).
5) Stop vehicle, and run engine at idle speed for 1 min.
6) Check if pending DTC exists by using scan tool. If not, check if oxygen sensor monitoring test has completed
by using scan tool. If not in both of above checks (i.e., no pending DTC and oxygen sensor monitoring test
not completed), check vehicle condition (environmental) and repeat step 3) through 6).
TROUBLESHOOTING
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester, on a level road.
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE
DIAG. FLOW
TABLE” in this sec-
tion.
2 HO2S-1 output voltage check :
1) Connect scan tool to DLC with ignition switch OFF.
2) Warm up engine to normal operating temperature and
keep it at 2000 r/min. for 60 sec.
3) Repeat racing engine (Repeat depressing accelerator
pedal 5 to 6 times continuously to enrich A/F mixture
and take foot off from pedal to enlean and check HO2S
output voltage displayed on scan tool. See Fig.
Is over 0.6 V and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-1 check :
1) With ignition switch OFF, disconnect HO2S-1 connec-
tor.
2) Check for proper connection to HO2S-1 at each termi-
nal.
3) If OK, connect voltmeter “1” and “2” terminal of HO2S-1
connector.
4) Start engine and check voltmeter while repeating rac-
ing engine.
Is over 0.6 V and below 0.3 V indicated?“RED” or “GRY/
YEL” circuit open or
short.
If wire and connec-
tions are OK, sub-
stitute a known-
good ECM (PCM)
and recheck.Replace HO2S-1.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-61
DTC P0135 HO2S-1 (Bank 1) Heater Circuit Malfunction
WIRING DIAGRAM
Refer to DTC P0130.
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and run
engine at idle speed for 5 min.
3) Check pending DTC by using scan tool.
TROUBLESHOOTING
DTC DETECTING CONDITION TROUBLE AREA
Following condition is detected when HO2S heater is
electrically live (2 driving cycle detection logic).
• Current of HO2S heater is 5.3 A or more or less than
0.09 A, or
• Voltage of HO2S heater is 14.0 V or higher or lower
than 11.7 V.HO2S-1 heater circuit
HO2S-1 heater
ECM (PCM)
HO2S heater relay
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE
DIAG. FLOW TABLE” in
this section.
2 HO2S-1 heater check :
1) Disconnect HO2S-1 coupler with ignition
switch OFF.
2) Check resistance between “3” and “4” termi-
nal of HO2S-1 coupler.
HO2S-1 heater resistance :
5.0 – 6.4
Ω
ΩΩ Ω (at 20°C (68°F))
Is it within above specification?Go to Step 3. Replace HO2S-1.
3 HO2S heater power supply check :
1) With ignition switch ON leaving engine OFF,
check voltage between E139-3 and ground,
E139-1 and ground. (See Fig.)
Is each voltage 10 – 14 V?Go to Step 4. “HO2S”, and/or “IG
METER” fuse blown.
If OK, faulty “BLK/WHT”
wire or “BLU/WHT” wire.

6-1-64 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data in ECM memory by using scan
tool and start engine.
3) Increase vehicle speed to 55 km/h (40 mph) or more.
4) Keep driving above vehicle speed till engine is warmed up completely (Changed of vehicle speed is permit-
ted in this step).
5) Keep driving 50 – 60 km/h (30 – 40 mph) for 8 min. or more.
6) Stop vehicle and check if pending DTC exists by using scan tool. If not, check if oxygen sensor heater moni-
toring test has completed by using scan tool. If not in both of above checks (i.e., no pending DTC and oxy-
gen sensor heater monitoring test not completed), check vehicle conditions (environmental) and repeat
Steps 3) through 6).
TROUBLESHOOTING
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 HO2S-2 output voltage check :
1) Connect scan tool to DLC with ignition
switch OFF.
2) Drive vehicle about 35 mph, 55 km/h for 2
min. or more.
3) Stop vehicle and check HO2S-2 output volt-
age displayed on scan tool while repeating
racing engine.
Is over and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-2 check :
1) With ignition switch OFF, disconnect HO2S-
2 coupler.
2) Connect voltmeter between “2” and “1” of
HO2S-2 coupler.
3) Start engine and check voltmeter while
repeating racing engine.
Is over and below 0.3 V indicated?“RED/BLK” or “GRY/YEL”
circuit open/short.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace HO2S-2.
4 Short term fuel trim check :
1) Run engine at 2000 r/min. for 60 sec.
2) With engine idling, check short term fuel
trim displayed on scan tool.
Is it within – 20 to +20 %?Intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Go to DTC P0171/P0172
Diag. Flow Table.

6-1-68 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC CONFIRMATION PROCEDURE
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and start
engine.
3) Increase vehicle speed to 55 km/h (35 mph) or more.
4) Keep driving above vehicle speed for 2 min. or more (Change of vehicle speed is permitted in this step).
5) Stop vehicle, and run engine at idle speed for 1 min.
6) Check if pending DTC exists by using scan tool. If not, check if oxygen sensor monitoring test has completed
by using scan tool. If not in both of above checks (i.e., no pending DTC and oxygen sensor monitoring test
not completed), check vehicle condition (environmental) and repeat step 3) through 6).
TROUBLESHOOTING
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester, on a level road.
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE
DIAG. FLOW
TABLE” in this sec-
tion.
2 HO2S-1 output voltage check :
1) Connect scan tool to DLC with ignition switch OFF.
2) Warm up engine to normal operating temperature and
keep it at 2000 r/min. for 60 sec.
3) Repeat racing engine (Repeat depressing accelerator
pedal 5 to 6 times continuously to enrich A/F mixture
and take foot off from pedal to enlean and check HO2S
output voltage displayed on scan tool. See Fig.
Is over 0.6 V and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-1 check :
1) With ignition switch OFF, disconnect HO2S-1 connec-
tor.
2) Check for proper connection to HO2S-1 at each termi-
nal.
3) If OK, connect voltmeter “1” and “2” terminal of HO2S-1
connector.
4) Start engine and check voltmeter while repeating rac-
ing engine.
Is over 0.6 V and below 0.3 V indicated?“RED/BLU” or
“GRY/YEL” circuit
open or short.
If wire and connec-
tions are OK, sub-
stitute a known-
good ECM (PCM)
and recheck.Replace HO2S-1.

6-1-70 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC P0155 HO2S-1 (Bank 2) Heater Circuit Malfunction
WIRING DIAGRAM
Refer to DTC P0150.
DTC DETECTING CONDITION AND TROUBLE AREA
DTC CONFIRMATION PROCEDURE
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and run
engine at idle speed for 5 min.
3) Check pending DTC by using scan tool.
TROUBLESHOOTING
DTC DETECTING CONDITION TROUBLE AREA
Following condition is detected when HO2S heater is
electrically live (2 driving cycle detection logic).
• Current of HO2S heater is 5.3 A or more or less than
0.09 A, or
• Voltage of HO2S heater is 14.0 V or higher or lower
than 11.7 V.HO2S-1 heater circuit
HO2S-1 heater
ECM (PCM)
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE
DIAG. FLOW TABLE” in
this section.
2 HO2S-1 heater check :
1) Disconnect HO2S-1 coupler with ignition
switch OFF.
2) Check resistance between “3” and “4” termi-
nal of HO2S-1 coupler.
HO2S-1 heater resistance :
5.0 – 6.4
Ω
ΩΩ Ω (at 20°C (68°F))
Is it within above specification?Go to Step 3. Replace HO2S-1.
3 HO2S heater power supply check :
1) With ignition switch ON leaving engine OFF,
check voltage between E139-3 and ground,
E139-1 and ground. (See Fig.)
Is each voltage 10 – 14 V?Go to Step 4. “HO2S”, and/or “IG
METER” fuse blown.
If OK, faulty “BLK/WHT”
wire or “BLU/WHT” wire.

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-73
1) Connect scan tool with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data in ECM memory by using scan
tool and start engine.
3) Increase vehicle speed to 55 km/h (40 mph) or more.
4) Keep driving above vehicle speed till engine is warmed up completely (Changed of vehicle speed is permit-
ted in this step).
5) Keep driving 50 – 60 km/h (30 – 40 mph) for 8 min. or more.
6) Stop vehicle and check if pending DTC exists by using scan tool. If not, check if oxygen sensor heater moni-
toring test has completed by using scan tool. If not in both of above checks (i.e., no pending DTC and oxy-
gen sensor heater monitoring test not completed), check vehicle conditions (environmental) and repeat
Steps 3) through 6).
TROUBLESHOOTING
NOTE:
Check to make sure that following conditions are satisfied when using this “DTC CONFIRMATION
PROCEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1 Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 HO2S-2 output voltage check :
1) Connect scan tool to DLC with ignition
switch OFF.
2) Drive vehicle about 35 mph, 55 km/h for 2
min. or more.
3) Stop vehicle and check HO2S-2 output volt-
age displayed on scan tool while repeating
racing engine.
Is over and below 0.3 V indicated?Go to Step 4. Go to Step 3.
3 HO2S-2 check :
1) With ignition switch OFF, disconnect HO2S-
2 coupler.
2) Connect voltmeter between “2” and “1” of
HO2S-2 coupler.
3) Start engine and check voltmeter while
repeating racing engine.
Is over and below 0.3 V indicated?“RED/YEL” or “GRY/YEL”
circuit open/short.
If wire and connection are
OK, substitute a known-
good ECM (PCM) and
recheck.Replace HO2S-2.
4 Short term fuel trim check :
1) Run engine at 2000 r/min. for 60 sec.
2) With engine idling, check short term fuel
trim displayed on scan tool.
Is it within – 20 to +20 %?Intermittent trouble or
faulty ECM (PCM).
Check for intermittent
referring to “INTERMIT-
TENT AND POOR CON-
NECTION” in Section 0A.Go to DTC P0174/P0175
Diag. Flow Table.

6-1-106 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
DTC CONFIRMATION PROCEDURE
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and warm up
engine completely.
3) Increase vehicle speed to 100 – 110 km/h (60 – 70 mph).
4) Release accelerator pedal and with engine brake applied, keep vehicle coasting for 5 seconds or more and
then stop vehicle.
5) Check pending DTC by using scan tool.
TROUBLESHOOTING
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester, on a level road.
NOTE:
Check to make sure that following condition is satisfied when using this “DTC CONFIRMATION PRO-
CEDURE”.
Intake air temp. : – 8°C (18°F) or higher
Engine coolant temp. : – 8 – 110°C (18 – 230°F)
Altitude (barometric pressure) : 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” per-
formed?Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE” in this
section.
2 Does speedometer indicate vehicle speed? Faulty “BLU/YEL” wire or
poor C51-1-14 connection.
If wire and connection are
OK, intermittent trouble or
faulty ECM (PCM).
Check for intermittent refer-
ring to “INTERMITTENT
AND POOR CONNECTION”
in Section 0A.Go to Step 3.
3 VSS power supply voltage check:
1) With ignition switch OFF, remove VSS
coupler.
2) With ignition switch ON leaving engine
OFF, check voltage between C20-3 and
C20-2 terminal of VSS coupler.
Is voltage 10 – 14 V?Go to Step 4.“BLK/BLU” or “BLK/YEL”
wire open/short.
4 VSS signal harness check:
1) With ignition switch ON leaving engine
OFF, check voltage between C20-1 and
C20-2 terminal of VSS coupler.
Is voltage 4 V or more?Go to Step 5. Go to Step 6.