2001 SUZUKI GRAND VITARA Pressure

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-31
Engine Diagnosis Table
Perform troubleshooting referring to following table when ECM (PCM) has detected no DTC and no abnormality
has been found in visual inspection and engine basic inspection previously.
Condition Possible Cause Correction
Hard starting
(Engine cranks OK)Faulty idle air control system “DIAG. FLOW TABLE B-4” in this
section.
Faulty ECT sensor or MAF sensor ECT sensor or MAF sensor in Sec-
tion 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Compression check in Section
6A2.
Faulty hydraulic valve lash adjuster Valve lash adjuster in Section 6A2.
Compression leak from valve seat Valves inspection in Section 6A2.
Sticky valve stem Valves inspection in Section 6A2.
Weak or damaged valve springs Valves spring inspection in Section
6A2.
Compression leak at cylinder head gasket Cylinder head inspection in Section
6A2.
Sticking or damaged piston ring Piston ring inspection in Section
6A2.
Worn piston, ring or cylinder Cylinders, pistons and piston rings
inspection in Section 6A2.
Malfunctioning PCV valve PCV system inspection in Section
6E2.
Engine has no power
Engine overheating Refer to “OVERHEATING” in this
table.
Defective spark plug Spark plugs in Section 6F2.
Faulty ignition coil with ignitor Ignition coil in Section 6F2.
Fuel pressure out of specification
(dirty fuel filter, dirty or clogged fuel hose or
pipe, malfunctioning fuel pressure regulator,
malfunctioning fuel pump)“DIAG. FLOW TABLE B-3” in this
section.
Maladjusted TP sensor installation angle TP sensor in Section 6E2.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty injector Fuel injector in Section 6E2.
Faulty TP sensor, ECT sensor or MAF sensor TP sensor, ECT sensor or MAF
sensor in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Refer to the same item in “HARD
STARTING” of this table.
Dragging brakes Diagnosis in Section 5.
Slipping clutch Diagnosis in Section 7C1.

6-1-32 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Improper engine idling
or engine fails to idleFaulty spark plug Spark plugs in Section 6F2.
Faulty ignition coil with ignitor Ignition coil in Section 6F2.
Fuel pressure out of specification “DIAG. FLOW TABLE B-3” in this
section.
Engine overheating Refer to “OVERHEATING” in this
table.
Maladjusted TP sensor installation angle if
adjustableTP sensor in Section 6E2.
Faulty idle air control system “DIAG. FLOW TABLE B-4” in this
section.
Faulty FIA (fast idle air) valve FIA valve in Section 6E2.
Faulty evaporative emission control system EVAP control system in Section
6E2.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty injector Fuel injection in Section 6E2.
Faulty ECT sensor, TP sensor or MAF sensor ECT sensor, TP sensor or MAF
sensor in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Refer to the same item in “HARD
STARTING” of this table.
Malfunctioning PCV valve PCV system inspection in Section
6E2.
Engine hesitates
(Momentary lack of
response as the accel-
erator is depressed.
Can occur at all vehi-
cle speeds.
Usually most severe
when first trying to
make the vehicle
move, as from a stop
sign.)Spark plug faulty or plug gap as out of adjust-
mentSpark plugs in Section 6F2.
Fuel pressure out of specification
(clogged fuel filter, faulty fuel pressure regula-
tor, clogged fuel filter, hose or pipe)“DIAG. FLOW TABLE B-3” in this
section.
Engine overheating Refer to “OVERHEATING” in this
table.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty injector Fuel injector in Section 6E2.
Faulty TP sensor, ECT sensor or MAF sensor TP sensor, ECT sensor or MAF
sensor in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Refer to the same item in “HARD
STARTING” of this table. Condition Possible Cause Correction

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-33
Surges
(Engine power varia-
tion under steady
throttle or cruise.
Feels like the vehicle
speeds up and down
with no change in the
accelerator pedal.)Defective spark plug
(excess carbon deposits, improper gap, and
burned electrodes, etc.)Spark plugs in Section 6F2.
Variable fuel pressure
(clogged fuel filter, kinky or damaged fuel hose
and line, faulty fuel pressure regulator)“DIAG. FLOW TABLE B-3” in this
section.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty MAF sensor MAF sensor in Section 6E2.
Faulty injector Fuel injector in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Excessive detonation
(The engine makes
sharp metallic knocks
that change with throt-
tle opening. Sounds
like pop corn pop-
ping.)Engine overheating Refer to “OVERHEATING” in this
table.
Faulty spark plug Spark plugs in Section 6F2.
Improper ignition timing Ignition timing in Section 6F2.
Clogged fuel filter and fuel lines Fuel pressure check in Section
6E2.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty ECT sensor or MAF sensor ECT sensor or MAF sensor in Sec-
tion 6E2.
Faulty injector Fuel injector in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Excessive carbon deposits in combustion
chamberPiston and cylinder head cleaning
in Section 6A2.
Poor knock sensor performance “DTC P0325 DIAG. FLOW TABLE”
in this section.
Overheating
Inoperative thermostat Thermostat in Section 6B.
Poor water pump performance Water pump in Section 6B.
Clogged or leaky radiator Radiator in Section 6B.
Improper engine oil grade Engine oil and oil filter change in
Section 0B.
Clogged oil filter or oil strainer Oil pressure check in Section 6A2.
Poor oil pump performance Oil pressure check in Section 6A2.
Dragging brakes Diagnosis in Section 5.
Slipping clutch Diagnosis in Section 7C1.
Blown cylinder head gasket Cylinder head inspection in Section
6A2. Condition Possible Cause Correction

6-1-34 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
Poor gasoline mileage
Faulty spark plug (improper gap, heavy depos-
its, and burned electrodes, etc.)Spark plugs in Section 6F2.
Fuel pressure out of specification “DIAG. FLOW TABLE B-3” in this
section.
Faulty TP sensor, ECT sensor or MAF sensor TP sensor, ECT sensor or MAF
sensor in Section 6E2.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty injector Fuel injector in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Refer to the same item in “HARD
STARTING” of this table.
Poor valve seating Valves inspection in Section 6A2.
Dragging brakes Diagnosis in Section 5.
Slipping clutch Diagnosis in Section 7C1.
Thermostat out of order Thermostat in Section 6B.
Improper tire pressure Diagnosis in Section 3.
Excessive engine oil
consumptionSticky piston ring Piston cleaning in Section 6A2.
Worn piston and cylinder Cylinders, pistons and piston rings
inspection in Section 6A2.
Worn piston ring groove and ring Pistons and piston rings inspection
in Section 6A2.
Improper location of piston ring gap Pistons installation in Section 6A2.
Worn or damaged valve stem seal Valves and cylinder head in Sec-
tion 6A2.
Worn valve stem Valves inspection in Section 6A2.
Low oil pressure
Improper oil viscosity Engine oil and oil filter change in
Section 0B.
Malfunctioning oil pressure switch Oil pressure switch inspection in
Section 8.
Clogged oil strainer Oil pan and oil pump strainer clean-
ing in Section 6A2.
Functional deterioration of oil pump Oil pump in Section 6A2.
Worn oil pump relief valve Oil pump in Section 6A2.
Excessive clearance in various sliding parts “INSPECTION” for each parts in
Section 6A2. Condition Possible Cause Correction

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-35
Engine noise
(Note : Before check-
ing the mechanical
noise, make sure the
followings : Ignition
timing is properly
adjusted, Specified
spark plug is used,
Specified fuel is used.)Faulty hydraulic valve lash adjuster Hydraulic valve lash adjuster in
Section 6A2.
Worn valve stem and guide Valves inspection in Section 6A2.
Weak or broken valve spring Valve springs inspection in Section
6A2.
Warped or bent valve Valves inspection in Section 6A2.
Loose camshaft housing bolts Camshafts in Section 6A2.
Worn piston, ring and cylinder bore Pistons and cylinders inspection in
Section 6A2.
Worn crankpin bearing Crankpin and connecting rod bear-
ing inspection in Section 6A2.
Worn crankpin Crankpin and connecting rod bear-
ing inspection in Section 6A2.
Loose connecting rod nuts Connecting rod installation in Sec-
tion 6A2.
Low oil pressure Refer to “LOW OIL PRESSURE” of
this table.
Worn crankshaft journal bearing Crankshaft and bearing inspection
in Section 6A2.
Worn crankshaft journal Crankshaft and bearing inspection
in Section 6A2.
Loose lower crankcase (bearing cap) bolts Crankshaft installation in Section
6A2.
Excessive crankshaft thrust play Crankshaft inspection in Section
6A2. Condition Possible Cause Correction

6-1-38 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
E61-22A/C condenser fan motor relay
(if equipped)10 – 14 VIgnition switch ON, A/C not oper-
ated and Engine coolant temp. :
less than 113°C, 235°F
E61-23 Fuel pump relay0 – 2.5 VFor 3 sec. after ignition switch ON
or while engine running
10 – 14 VAfter 3 sec. from ignition switch ON
with engine stopped
E61-24Ground for CO adjusting resistor
(if equipped)––
E61-25 – – –
E61-26 – – –
E61-27 – – –
E61-28 Fuel level sensor 0 – 6 VIgnition switch ON
Voltage depends on fuel level
E61-29Diag. switch terminal
(vehicle with monitor connector)10 – 14 V Ignition switch ON
E61-30 ABS control module 10 – 14 V Ignition switch ON
E61-31Power/Normal change switch
(A/T vehicle)0 – 1 VIgnition switch ON, P/N change
switch : POWER mode
10 – 14 VIgnition switch ON, P/N change
switch : NORMAL mode
E61-32 Lighting switch0 – 1 VIgnition switch ON, lighting switch
OFF
10 – 14 VIgnition switch ON, lighting switch
ON
E61-33 Overdrive cut switch (A/T vehicle)10 – 14 VIgnition switch ON, overdrive cut
switch released
0 – 1 VIgnition switch ON, overdrive cut
switch pressed
E61-34 Stop lamp switch0 – 1 VBrake pedal released (switch OFF),
Ignition switch ON
10 – 14 VBrake pedal depressed (switch ON),
Ignition switch ON
E61-35 Cruise control module (if equipped) 10 – 14 V Ignition switch ON
C51-3-1 Intake air temp. sensor 2.2 – 3.0 VIgnition switch ON, Sensor ambient
temp. : 20°C, 68°F
C51-3-2 Engine coolant temp. sensor 0.5 – 0.9 VIgnition switch ON, Engine coolant
temp. : 80°C, 176°F
C51-3-3 Knock sensor About 2.5 VWith engine running at idle after
warned up
C51-3-4 Power source 10 – 14 V Ignition switch ON
C51-3-5 Ground for MAF sensor – –
C51-3-6 Ground – –
C51-3-7 4WD switch0 – 1 VIgnition switch ON, Transfer lever :
4H or 4L range
10 – 14 VIgnition switch ON, Transfer lever :
2H range
C51-3-8 Manifold absolute pressure sensor 3.3 – 4.3 V Ignition switch ON and engine stops TERMINAL CIRCUIT NORMAL VOLTAGE CONDITION

ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-39
C51-3-9 Throttle position sensor0.5 – 1.2 VIgnition switch ON, Throttle valve at
idle position
3.4 – 4.7 VIgnition switch ON, Throttle valve at
full open position
C51-3-10 Mass air flow sensor1.0 – 1.6 V Ignition switch ON and engine stops
1.7 – 2.0 V With engine running at idle speed
C51-3-11Heated oxygen sensor-1 (bank 1)
(if equipped)Deflects between
over and under 0.45 VWhile engine running at 2,000 r/min.
for 1 min. or longer after warmed up
C51-3-12 Ground for TP sensor – –
C51-3-13 Power source for TP sensor
4.75 – 5.25 V Ignition switch ON
C51-3-14 Power source for MAP sensor
C51-3-15 Power source 10 – 14 V Ignition switch ON
C51-3-16 – – –
C51-3-17 Ground – –
C51-3-18Pressure switch in 4WD air pump
assembly10 – 14 VIgnition switch ON, Transfer lever :
4H or 4L range
0 – 1 VIgnition switch ON, Transfer lever :
2H range
C51-3-19 – – –
C51-3-20 Ignition switch 10 – 14 V Ignition switch ON
C51-3-21Heated oxygen sensor-1 (bank 2)
(if equipped)Deflects between over
and under 0.45 VWhile engine running at 2,000 r/min.
for 1 min. or longer after warmed up
C51-3-22Heated oxygen sensor-2 (bank 1)
(if equipped)Deflects between over
and under 0.45 VWhile engine running at 2,000 r/min.
for 1 min. or longer after warmed up
C51-3-23Heated oxygen sensor-2 (bank 2)
(if equipped)Deflects between over
and under 0.45 VWhile engine running at 2,000 r/min.
for 1 min. or longer after warmed up
C51-3-24 Ground for ECT sensor – –
C51-3-25 Ground for IAT sensor, MAP sensor – –
C51-3-26 Ground for CMP sensor – –
C51-1-1 Shift solenoid B (A/T vehicle) 0 – 1 V Ignition switch ON
C51-1-2 Shift solenoid A (A/T vehicle) 10 – 14 V Ignition switch ON
C51-1-3 – – –
C51-1-4 IAC valve (stepper motor coil 2) – –
C51-1-5 IAC valve (stepper motor coil 1) – –
C51-1-6Transmission range switch “R”
(A/T vehicle)10 – 14 VIgnition switch ON, selector lever :
“R” range
0 – 1 VIgnition switch ON, selector lever :
Other than “R”
C51-1-7Transmission range switch “P”
(A/T vehicle)10 – 14 VIgnition switch ON, selector lever :
“P” range
0 – 1 VIgnition switch ON, selector lever :
Other than “P” range
C51-1-8 TCC solenoid (A/T vehicle) 0 – 1 V Ignition switch ON
C51-1-9 4WD air pump assembly10 – 14 VIgnition switch ON, Transfer lever :
4H or 4L range
0 – 1 VIgnition switch ON, Transfer lever :
2H range TERMINAL CIRCUIT NORMAL VOLTAGE CONDITION

6-1-40 ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE)
C51-1-10A/T input speed sensor (–)
(A/T vehicle)About 2.5 V Ignition switch ON
C51-1-11A/T input speed sensor (+)
(A/T vehicle)About 2.5 V Ignition switch ON
C51-1-12 Camshaft position sensor 1Deflects between
0 – 1 V and 4 – 6 VIgnition switch ON, crankshaft
turned slowly
C51-1-13 Camshaft position sensor 2Deflects between
0 – 1 V and 4 – 6 VIgnition switch ON, crankshaft
turned slowly
C51-1-14 Vehicle speed sensorDeflects between
0 – 1 V and over 4VIgnition switch ON, Rear right tire
turned slowly with rear left tire
locked
C51-1-15 EVAP canister purge valve 10 – 14 V Ignition switch ON
C51-1-16 IAC valve (stepper motor coil 4) – –
C51-1-17 IAC valve (stepper motor coil 3) – –
C51-1-18Transmission range switch “D”
(A/T vehicle)10 – 14 VIgnition switch ON, selector lever :
“D” range
0 – 1 VIgnition switch ON, selector lever :
Other than “D” range
C51-1-19Transmission range switch “N”
(A/T vehicle)10 – 14 VIgnition switch ON, selector lever :
“N” range
0 – 1 VIgnition switch ON, selector lever :
Other than “N” range
C51-1-20Shield wire ground for A/T output
speed sensor (A/T vehicle)––
C51-1-21Shield wire ground for A/T input
speed sensor (A/T vehicle)––
C51-1-22A/T output speed sensor (–)
(A/T vehicle)About 2.5 V Ignition switch ON
C51-1-23A/T output speed sensor (+)
(A/T vehicle)About 2.5 V Ignition switch ON
C51-1-24 Engine start signal10 – 14 V While engine cranking
0 – 1 V Other than above
C51-1-25 Power steering pressure switch10 – 14 V Ignition switch ON
0 – 1 VWith engine running at idle speed,
turning steering wheel to the right or
left as far as it stops
C51-1-26 4WD low switch0 – 1 VIgnition switch ON, Transfer lever :
4WD low range
10 – 14 VIgnition switch ON, Transfer lever :
4H or 2H range
C51-1-27Transmission range switch “L”
(A/T vehicle)10 – 14 VIgnition switch ON, selector lever :
“L” range
0 – 1 VIgnition switch ON, selector lever :
Other than “L” range
C51-1-28Transmission range switch “2”
(A/T vehicle)10 – 14 VIgnition switch ON, selector lever :
“2” range
0 – 1 VIgnition switch ON, selector lever :
Other than “2” range TERMINAL CIRCUIT NORMAL VOLTAGE CONDITION