2004 ISUZU TF SERIES coolant temperature

ENGINE DRIVEABILITY AND EMISSIONS 6E–3
Diagnostic Aids .......................................... 6E-139
Diagnostic Trouble Code (DTC) P0118
Engine Coolant Temperature Sensor High
Input ......................................................... 6E-140
DIAGNOSTIC TROUBLE CODE (DTC) P0122
THROTTLE POSITION SENSOR LOW
INPUT ......................................................... 6E-143
Circuit Description ..................................... 6E-143
Diagnostic Aids .......................................... 6E-143
Diagnostic Trouble Code (DTC) P0122 Throttle
Position Sensor Low Input ....................... 6E-144
DIAGNOSTIC TROUBLE CODE (DTC) P0123
THROTTLE POSITION SENSOR HIGH
INPUT ...................................................... 6E-147
Circuit Description ..................................... 6E-147
Diagnostic Aids .......................................... 6E-147
Diagnostic Trouble Code (DTC) P0123 Throttle
Position Sensor High Input ...................... 6E-148
DIAGNOSTIC TROUBLE CODE (DTC) P0131
O
2 SENSOR CIRCUIT LOW VOLTAGE
(BANK 1 SENSOR 1) ................................. 6E-150
Circuit Description ..................................... 6E-150
Diagnostic Aids .......................................... 6E-150
Diagnostic Trouble Code (DTC) P0131
O
2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
6E-160
DIAGNOSTIC TROUBLE CODE (DTC) P0132 O
2
SENSOR CIRCUIT HIGH VOLTAGE (BANK 1
SENSOR 1) ................................................ 6E-155
Circuit Description ..................................... 6E-155
Diagnostic Aids .......................................... 6E-155
Diagnostic Trouble Code (DTC) P0132
O
2 Sensor Circuit High Voltage
(Bank 1 Sensor 1) .................................... 6E-156
DIAGNOSTIC TROUBLE CODE (DTC) P0134
O
2 SENSOR NO ACTIVITY DEFECTED
(BANK 1 SENSOR 1) ................................. 6E-159
Circuit Description ..................................... 6E-159
Diagnostic Aids .......................................... 6E-160
Diagnostic Trouble Code (DTC) P0134
O
2 Sensor Circuit No Activity Detected
(Bank 1 Sensor 1) .................................... 6E-160
DIAGNOSTIC TROUBLE CODE (DTC) P0135
O
2 SENSOR HEATER CIRCUIT
(BANK 1 SENSOR 1) ................................. 6E-163
Circuit Description ..................................... 6E-163
Diagnostic Aids .......................................... 6E-164
Diagnostic Trouble Code (DTC) P0135
O
2 Sensor Heater Circuit (Bank 1 Sensor 1) 6E-164
DIAGNOSTIC TROUBLE CODE (DTC) P0201
INJECTOR 1 CONTROL CIRCUIT ............. 6E-167
DIAGNOSTIC TROUBLE CODE (DTC) P0202 INJECTOR 2 CONTROL CIRCUIT ............. 6E-167
DIAGNOSTIC TROUBLE CODE (DTC) P0203
INJECTOR 3 CONTROL CIRCUIT ............. 6E-167
DIAGNOSTIC TROUBLE CODE (DTC) P0204
INJECTOR 4 CONTROL CIRCUIT ............. 6E-167
Circuit Description ...................................... 6E-167
Diagnostic Aids .......................................... 6E-168
Diagnostic Trouble Code (DTC) P0201
Injector 1 Control Circuit .......................... 6E-168
Diagnostic Trouble Code (DTC) P0202
Injector 2 Control Circuit .......................... 6E-168
Diagnostic Trouble Code (DTC) P0203
Injector 3 Control Circuit .......................... 6E-168
Diagnostic Trouble Code (DTC) P0204
Injector 4 Control Circuit .......................... 6E-168
DIAGNOSTIC TROUBLE CODE (DTC) P0325
KNOCK SENSOR (KS) MODULE CIRCUIT 6E-174
Circuit Description ...................................... 6E-174
Diagnostic Aids .......................................... 6E-174
Diagnostic Trouble Code (DTC) P0325
Knock
Sensor Module Circuit ............................. 6E-174
DIAGNOSTIC TROUBLE CODE (DTC) P0327
KNOCK SENSOR (KS) CIRCUIT ............... 6E-177
Circuit Description ...................................... 6E-177
Diagnostic Aids .......................................... 6E-177
Diagnostic Trouble Code (DTC) P0327
Knock Sensor Circuit ............................... 6E-178
DIAGNOSTIC TROUBLE CODE (DTC) P0336
CRANKSHAFT POSITION (CKP) SENSOR
CIRCUIT RANGE/PERFORMANCE (58X) . 6E-180
DIAGNOSTIC TROUBLE CODE (DTC) P0337
CRANKSHAFT POSITION (CKP) SENSOR
CIRCUIT LOW INPUT (58X) ...................... 6E-180
Circuit Description ...................................... 6E-180
Diagnostic Aids .......................................... 6E-181
Diagnostic Trouble Code (DTC) P0336
Crankshaft Position Sensor Circuit
Range/performance (58x) ........................ 6E-181
Diagnostic Trouble Code (DTC) P0337
Crankshaft Position Sensor Circuit Low
Input (58x) ............................................... 6E-181
DIAGNOSTIC TROUBLE CODE (DTC) P0351
IGNITION 1 CONTROL CIRCUIT ............... 6E-186
DIAGNOSTIC TROUBLE CODE (DTC) P0352
IGNITION 2 CONTROL CIRCUIT ............... 6E-186
Circuit Description ...................................... 6E-186
Diagnostic Aids .......................................... 6E-186
Diagnostic Trouble Code (DTC) P0351
Ignition 1 Control Circuit .......................... 6E-187
Diagnostic Trouble Code (DTC) P0352
Ignition 2 Control Circuit .......................... 6E-187

ENGINE DRIVEABILITY AND EMISSIONS 6E–5
ENGINE CRANKS BUT WILL NOT RUN ..... 6E-233
HARD START SYMPTOM ............................ 6E-236
ROUGH, UNSTABLE, OR INCORRECT IDLE,
STALLING SYMPTOM ............................... 6E-239
SURGES AND/OR CHUGS SYMPTOM ...... 6E-242
HESITATION, SAG, STUMBLE SYMPTOM 6E-245
CUTS OUT, MISSES SYMPTOM ................. 6E-248
LACK OF POWER, SLUGGISH OR SPONGY
SYMPTOM ................................................. 6E-251
DETONATION/SPARK KNOCK SYMPTOM 6E-254
POOR FUEL ECONOMY SYMPTOM .......... 6E-256
EXCESSIVE EXHAUST EMISSIONS OR
ODORS SYMPTOM ................................... 6E-258
DIESELING, RUN-ON SYMPTOM ............... 6E-261
BACKFIRE SYMPTOM ................................. 6E-262
ON-VEHICLE SERVICE PROCEDURE ....... 6E-264
ENGINE CONTROL MODULE (ECM) .......... 6E-264
CRANKSHAFT POSITION (CKP) SENSOR 6E-264
ENGINE COOLANT TEMPERATURE (ECT)
SENSOR .................................................... 6E-265
INTAKE AIR TEMPERATURE (IAT) SENSOR 6E-265
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR .................................................... 6E-266
THROTTLE POSITION SENSOR (TPS) ...... 6E-266
IDLE AIR CONTROL (IAC) VALVE .............. 6E-267
KNOCK SENSOR ......................................... 6E-268
POWER STEERING PRESSURE (PSP)
SWITCH ..................................................... 6E-268
HEATED OXYGEN SENSOR (HO2S) ......... 6E-269
EVAP CANISTER PURGE VALVE SOLENOID 6E-269
FUEL PRESSURE RELIEF .......................... 6E-270
FUEL RAIL ASSEMBLY ............................... 6E-270
FUEL INJECTOR .......................................... 6E-271
FUEL PRESSURE REGULATOR ................ 6E-273
IGNITION COIL ............................................ 6E-275
SPARK PLUGS ............................................ 6E-275
SPARK PLUG CABLES ................................ 6E-277
EMISSION CONTROL ; CO ADJUSTER (W/O
CATALYSTIC CONVERTER) .................. 6E-277
SPECIAL SERVICE TOOLS ......................... 6E-279

6E–6 ENGINE DRIVEABILITY AND EMISSIONS
ABBREVIATIONS CHARTS
A bbreviations A ppellation
A/C Air Conditioner
A/T Automatic Transmission
ACC Accessory
BLK Black
BLU Blue
BRN Brown
CEL Check Engine Lamp
CKP Crankshaft Position
DLC Data Link Connector
DTC Diagnostic Trouble Code
DVM Digital Volt Meter
ECM Engine Control Module
ECT Engine Coolant Temperature
EEPROM Electrically Erasable & Programmable Read Only Memory
EVAP Evaporative Emission
EVRV Electric Vacuum Regulating Valve
EXH Exhaust
FT Fuel Temperature
GND Ground
GRY Gray
HOS2 Heated Ox ygen Sensor
IAC Idel Air Control
IAT Intake Air Temperature
IG Ignition
ITP Intake Throttle Position
KS Knock Sensor
M/T Manual Transmission
MAP Manifold Absolute Pressure
MIL Malfunction Indicator Lamp
OBD On-Board Diagnostic
ORN Orange
OT Oil Temperature
PNK Pink
RED Red
SW Switch
TB Throttle Body
TEMP Temperature
TP Throttle Posi tion
VCC Voltage Constant Control
VSS Vehicle Speed Sensor
WHT Whi te
Y EL Yellow

ENGINE DRIVEABILITY AND EMISSIONS 6E–7
COMPONENT LOCATORt
1
2 4
3
(1)
(2)Air Cleaner
Idle Air Control (IAC) Valve (3)
(4)Engine Coolant Temperature (ECT) Sensor
Engine Control Module (ECM)
3 2 1
(1)
(2)
(3)Intake Air Temperature (IAT) Sensor
Idle Air Control (IAC) Valve
Throttle Position Sensor (TPS)

ENGINE DRIVEABILITY AND EMISSIONS 6E–9
(1) Crankshaft Position (CKP) Sensor(1) Knock Sensor (KS)
(1)
(2)Engine Coolant Temperature (ECT) Sensor
Thermo Meter Sensor
21
(1) Manifold Absolute Pressure (MAP) Sensor
(1)
(2)Throttle Position Sensor
Idle Air Control (IAC) Valve
2
1
(1) EVAP Purge Solenoid

6E–48 ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR ECM AND
SENSORS
Engine Control Module (ECM)
The engine control module (ECM) is located on the
intake manifold. The ECM controls the following.
Fuel metering system
Ignition timing
On-board diagnostics for electrical functions.
The ECM constantly observes the information from vari-
ous sensors. The ECM controls the systems that affect
vehicle performance. And it performs the diagnostic
function of the system.
The function can recognize operational problems, and
warn to the driver through the check engine lamp, and
store diagnostic trouble code (DTC). DTCs identify the
problem areas to aid the technician in marking repairs.
The input / output devices in the ECM include analog to
digital converts, signal buffers, counters and drivers.
The ECM controls most components with electronic
switches which complete a ground circuit when turned
on.
Inputs (Operating condition read):
Battery voltage
Electrical ignition
Ex haust oxygen content
Intake manifold pressure
Intake air temperature
Engine coolant temperature
Crankshaft positionKnock signal
Throttle position
Vehicle speed
Power steering pressure
Air conditioning request on or off
Outputs (Systems controlled):
Ignition control
Fuel control
Idle air control
Fuel pump
EVAP canister purge
Air conditioning
Diagnostics functions
Manifold Absolute Pressure (MAP) Sensor
The MAP sensor is a strain gage. A pressure strains the
resistance on the silicon base. At that time the
resistance value changes. And it changes voltage. In
other words it measures a pressure value. It is installed
to the intake manifold. Output voltage of the MAP
sensor is low as pressure is low. (1) J1 Port
(2) J2 Port
12
C h arac teris tic of MA P S ens or -R ef erenc e-
0 0.51 1.52 2.53 3.54 4.55
15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Mani fold A bs olute P res s ure (K P a) (T ec h2 Reading)
Output Voltage (V)

ENGINE DRIVEABILITY AND EMISSIONS 6E–49
Throttle Position Sensor (TPS)
The TPS is a potentiometer connected to throttle shaft
on the throttle body.
The engine control module (ECM) monitors the voltage
on the signal line and calculates throttle position. As the
throttle valve angle is changed when accelerator pedal
moved. The TPS signal also changed at a moved
throttle valve. As the throttle valve opens, the output
increases so that the output voltage should be high.
The throttle body has a throttle plate to control the
amount of the air delivered to the engine.
Engine coolant is directed through a coolant cavity in
the throttle body to warm the throttle valve and to
prevent icing.
Idle Air Control (IAC) Valve
The idle air control valve (IAC) valve is two directional
and gives 2-way control. With power supply to the coils
controlled steps by the engine control module (ECM),
the IAC valve's pintle is moved to adjust idle speed,
raising it for fast idle when cold or there is ex tra load
from the air conditioning or power steering.
By moving the pintle in (to decrease air flow) or out (to
increase air flow), a controlled amount of the air can
move around the throttle plate. If the engine speed is
too low, the engine control module (ECM) will retract the
IAC pintle, resulting in more air moving past the throttle
plate to increase the engine speed.
If the engine speed is too high, the engine control
module (ECM) will ex tend the IAC pintle, allowing less
air to move past the throttle plate, decreasing the
engine speed.
The IAC pintle valve moves in small step called counts.
During idle, the proper position of the IAC pintle is
calculated by the engine control module (ECM) based
on battery voltage, coolant temperature, engine load,
and engine speed.
If the engine speed drops below a specified value, and
the throttle plate is closed, the engine control module
(ECM) senses a near-stall condition. The engine control
module (ECM) will then calculate a new IAC pintle valve
position to prevent stalls.
If the IAC valve is disconnected and reconnected with
the engine running, the idle speed will be wrong. In this
case, the IAC must be reset. The IAC resets when the
key is cycled “On” then “Off”. When servicing the IAC, it
should only be disconnected or connected with the
ignition “Off”.
The position of the IAC pintle valve affects engine start-
up and the idle characteristic of the vehicle.
If the IAC pintle is fully open, too much air will be
allowed into the manifold. This results in high idle
speed, along with possible hard starting and lean air/
fuel ratio. (1) Throttle Position Sensor
(2) Idle Air Control (IAC) Valve
1
2
C haract erist ic of TPS -R ef erenc e-
0 0. 51 1. 52 2. 53 3. 54 4. 55
0 102030405060708090100
Th rot t le An gle ( % ) ( Tec h 2 R ea di n g)
Output Voltage (V)
StepCoilAB CDCoil A High
(EC M J1-28)On On
Coil A Low
(EC M J1-30)On On
Coil B High
(EC M J1-13)On On
Coil B Low
(EC M J1-29)On On

(IAC Valve Close Direction)
(IAC Valve Open Direction)

6E–50 ENGINE DRIVEABILITY AND EMISSIONS
Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor, which sends a
signal necessary for deciding on injection timing to the
ECM, is mounted on the left-hand side of the cylinder
block just back of the A/C compressor.
The crankshaft has a 58 teeth press-fit timing disc, from
which the CKP sensor reads the position of the
crankshaft at all the times. It converts this to an
electrical signal, which it sends to the ECM.
Using the 58 X signals per rotation and the timing-mark
signal sent by the CKP sensor, the ECM is able to
accurately calculate engine speed and crank position.
The ECM converts the 58 X signals into square signals.
This converted signal is sent from the ECM terminal J2-
25 to the tachometer.
Knock Sensor (KS)
The knock sensor (KS) contains an element that
converts detection of knock into an electrical signal, and
is mounted on cylinder block wall.
When the ECM receives a signal that indicates knock,
the ECM orders ignition timing to be adjusted to
compensate.
Engine Coolant Temperature (ECT) Sensor
The ECT sensor is a thermistor. A temperature changes
the resistance value. And it changes voltage. In other
words it measures a temperature value. It is installed on
the coolant stream. Low coolant temperature produces
a high resistance.
The ECM supplies 5 volts signal to the ECT sensor
through resisters in the ECM and measures the voltage.
The signal voltage will be high when the engine
temperature is cold, and it will be low when the engine
temperature is hot.

Ch aract erist ic of ECT Sens or -Ref erenc e-
10 100 1000 10000 100000
-20-100 10203040 5060708090100110120
Cool ant Temp. ( deg . C ) ( Tech2 R eadi ng )
Resistance (ohm) (Solid Line)