
6E–39 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Engine Control Module ECM
Diagnosis
To read and clear diagnostic trouble codes, use a Tech 2.
IMPORTANT:Use of a Tech 2 is recommended to clear
diagnostic trouble codes from the ECM memory.
Diagnostic trouble codes can also be cleared by turning
the ignition “OFF” and disconnecting the battery power
from the ECM for 30 seconds. Turning off the ignition and
disconnecting the battery power from the ECM will cause
all diagnostic information in the ECM memory to be
cleared. Therefore, all the diagnostic tests will have to be
re-run.
Since the ECM can have a failure which may affect only
one circuit, following the diagnostic procedures in this
section will determine which circuit has a problem and
where it is.
If a diagnostic chart indicates that the ECM connections
or the ECM is the cause of a problem, and the ECM is
replaced, but this does not correct the problem, one of the
following may be the reason:
There is a problem with the ECM terminal
connections. The terminals may have to be removed
from the connector in order to check them properly.
The problem is intermittent. This means that the
problem is not present at the time the system is being
checked. In this case, refer to the
Symptoms portion
of the manual and make a careful physical inspection
of all components and wiring associated with the
affected system.
There is a shorted solenoid, relay coil, or harness.
Solenoids and relays are turned “ON” and “OFF” by
the ECM using internal electronic switches called
drivers. A shorted solenoid, relay coil, or harness will
not damage the ECM but will cause the solenoid or
relay to be inoperative.
Multiple ECM Information Sensor
DTCS Set
Circuit Description
The Engine Control Module ECM monitors various
sensors to determine the engine operating conditions.
The ECM controls fuel delivery, spark advance,
transmission operation, 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
determines the status of the following sensors by
monitoring the voltage present between the 5-volt supply
and the resistor:
The fuel temperature (FT) sensor
The engine coolant temperature (ECT) sensor
The Intake air temperature (IAT) sensor
The ECM provides the following sensors with a 5-volt
reference and a sensor ground signal:
The Intake throttle position sensor
The manifold absolute pressure sensor
The rail pressure sensor
The accelerator position sensor
The oil temperature sensor
The camshaft position sensor
The crankshaft position sensor
The EGR pressure sensor
The ECM monitors the signals from these sensors in
order to determine their operating status.
Diagnostic Aids
IMPORTANT:Be sure to inspect ECM and engine
grounds for being secure and clean.
A short to voltage in one of the sensor input circuits may
cause one or more of the following DTCs to be set:
P0337
P0342
P1193
P1404
P1405
P1488
IMPORTANT:If a sensor input circuit has been shorted
to voltage, ensure 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:
P0337
P0342
P0117
A short to ground in the 5-volt reference A or B circuit will
cause one or more of the following DTCs to be set:
P0112
P0117
P0182
P0197
An open in the 5-volt reference circuit A, between the
ECM and the splice will cause one or more of the following
DTCs to be set:
P0107
P0405
P1194
P0122
An open in the 5-volt reference circuit B, between the
ECM and the splice will cause one or more of the following
DTCs to be set:
P1485
Check for the following conditions:
Poor connection at ECM. Inspect the harness
connectors for backed-out terminals, improper
mating, broken locks, improperly formed or damage
terminals, and a poor terminal-to-wire connection.
Damaged harness. Inspect the wiring harness for
damage. If the harness is not damaged, observe an
affected sensor’s displayed value on the Tech 2 with
the ignition “ON” and the engine “OFF” while you
move the connectors and the wiring harnesses
related to the following sensors:
ECT Sensor

6E–41 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
EGR (Exhaust Gas Recirculation)
Diagnosis
A diagnosis of the EGR system is covered by DTC
P1403.
EGR VSV circuit diagnosis is covered by DTC P1404.
EGR pressure sensor diagnosis is covered by DTC
P405 and/or P406.
EGR EVRV circuit diagnosis is covered by DTC
P1405. Refer to the DTC charts.
Tech 2 Data Definitions and Ranges
A/C CLUTCH–Tech 2 Displays ON or OFF–
Indicates whether the A/C has commanded the A/C
clutch ON.
MAP kPa — Tech 2 Range 10-105 kPa/0.00-5.00
Vo l t s —
The manifold absolute pressure reading is determined
from the MAP sensor signal monitored during key up and
wide open throttle (WOT) conditions. The manifold
absolute pressure is used to compensate for altitude
differences and is normally displayed around “61-104”
depending on altitude and manifold absolute pressure.
CMP ACT. COUNTER –Cam Position
DESIRED IDLE — Tech 2 Range 0-3187 RPM —
The idle speed that the ECM is commanding. The ECM
will compensate for various engine loads based on engine
coolant temperature, to keep the engine at the desired
speed.
ECT — (Engine Coolant Temperature) Tech 2
Range –40
C to 151C (–40F to 304F) —
The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the ECM. The ECM applies 5 volts to the
ECT sensor circuit. The sensor is a thermistor which
changes internal resistance as temperature changes.
When the sensor is cold (high resistance), the ECM
monitors a high signal voltage and interprets that as a cold
engine. As the sensor warms (decreasing resistance),
the voltage signal will decrease and the ECM will interpret
the lower voltage as a warm engine.
ENGINE RUN TIME — Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec —
Indicates the time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to
00:00:00.
ENGINE SPEED — Range 0-9999 RPM —
Engine speed is computed by the ECM from the 57X
reference input. It should remain close to desired idle
under various engine loads with engine idling.Air Intake Valve meter POSITION — Tech 2 Range
0-100 % —
IAT (INTAKE AIR TEMPERATURE)— Tech 2 Range
–40
C to 151C (–40F to 304F) —
The ECM converts the resistance of the intake air
temperature sensor to degrees. Intake air temperature
(IAT) is used by the ECM to adjust fuel delivery and spark
timing according to incoming air density.
MAP — Tech 2 Range 10-105 kPa (0.00-4.97 Volts)—
The manifold absolute pressure (MAP) sensor measures
the change in the boost pressure.
MIL — Tech 2 Displays ON or OFF —
Indicates the ECM commanded state of the malfunction
indicator lamp.
AP — Tech 2 Range 0%-100% —
AP (Accelerator position) angle is computed by the ECM
from the AP sensor voltage. AP angle should display
“0%” at idle and “100%” at wide open throttle.
AP SENSOR — Tech 2 Range 0.00-5.00 Volts —
The voltage being monitored by the ECM on the AP
sensor signal circuit.
VEHICLE SPEED—Tech 2 Range 0-255 km/h (0-155
mph)–
The vehicle speed sensor signal is converted into km/h
and mph for display.
Typical Scan Data Values
Use the Typical Scan Data Values Table only after the
On-Board Diagnostic System Check has been
completed, no DTC(s) were noted, and you have
determined that the on-board diagnostics are functioning
properly. Tech 2 values from a properly-running engine
may be used for comparison with the engine you are
diagnosing. The typical scan data values represent
values that would be seen on a normally-running engine.
NOTE: A Tech 2 that displays faulty data should not be
used, and the problem should be reported to the Tech 2
manufacturer. Use of a faulty Tech 2 can result in
misdiagnosis and unnecessary replacement of parts.
Only the parameters listed below are referred to in this
service manual for use in diagnosis. For further
information on using the Tech 2 to diagnose the ECM and
related sensors, refer to the applicable reference section
listed below. If all values are within the typical range
described below, refer to the
Symptoms section for
diagnosis.
Test Conditions
Engine running, lower radiator hose hot, transmission in
park or neutral, accessaries off, brake not applied and air
conditioning off.

6E–42
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
4JX1-TC Engine (Automatic and Manual Transmission)
Te c h 2
Parameter
Data ListUnits
DisplayedTy p i c a l D a t a
Values (IDLE)Typical Data
Va l u e s
(2500 RPM)Refer To
Battery VoltageEngineVo l t s12.5 14.513 15General Description
Ignition StatusEngineOn/OffOnOnGeneral Description
Ignition Relay2EngineOn/OffOnOnGeneral Description
Idle SwitchEngineInactive/
Active——DTC P0510, P1510
Manifold
Absolute
PressureEngineKPa96 106110 150General Description
DTC P0107, P0108
Rail Oil
PressureEngineMPa3.5 54.5 10General Description
DTC P0192, P0193
Desired Rail Oil
PressureEngineMPa4 55 9General Description
DTC P0192, P0193
Fuel
TemperatureEngineC (F)75 8575 85DTC P0182, P0183
Quick Warming
SwitchEngineOn/OffOffOffDTC P0380
Thermo RelayEngineOn/Off——DTC P1655
Actual EGR
PressureEngineKPa58 60M/T 63 66
A/T 95
105
DTC P0405, P0406
Barometric
PressureEngineKPa98 10298 102General Description
Relative EGR
PressureEngineKPa–38 –45M/T –34 –37
A/T 0General Description
Desired EGR
PressureEngineKPa–43 –40M/T 36
A/T 0General Description
Brake SwitchEngineInactive/
Active——DTC P1588
GearEngine————
Vehicle SpeedEngineKm/h00Transmission Diagnosis
Rail Pressure
Control ValveEngine%17 2218 27DTC P1193
EGR StatusEngineDisable/
EnableEnableM/T Enable
A/T DisableGeneral Description
EGR Switching
Va l v eEngineOn/Off——General Description
Throttle Motor
Position SensorEngineVo l t s3.1 3.90.2 0.9DTC P1485, P1486,
P1487
Throttle Motor
PositionEngineSteps
0 1.00 1.0
DTC P1488
Delirered Fuel
QuantityEnginemm 3/st
6 106 12
General Description
Injector StatusEngineDisable/
EnableEnableEnableDTC P0201, P0202,
P0203, P0204, General
Description
Injector Pulse
WidthEnginems0.9 1.250.7 1.1General Description
Injector Start
OffsetEngineCA——General Description

6E–43 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Te c h 2
ParameterData ListUnits
DisplayedTy p i c a l D a t a
Values (IDLE)Typical Data
Va l u e s
(2500 RPM)Refer To
Exhaust VSV1EngineOn/OffOffOffDTC P0475
Exhaust VSV2EngineOn/OffOffOffDTC P1475
Decelevation
Fuel Cut OffEngineInactive/
Active——General Description
Glow Time
LampEngineOn/OffOffOffDTC P0381
Glow Time
RelayEngineOn/OffOffOffDTC P0380
Diagnostic
RequestEngineInactive
12V/
Active 0V——General Description
A/C ClutchEngineOn/OffOffOffGeneral Description
Desired IdleEngineRPM720—General Description
ECT (Engine
Coolant Temp)EngineC (F)80 9080 90General Description
ECT
Engine SpeedEngineRPM7202500DTC P0219
MAT (Intake Air
Te m p )EngineC (F)65 8065 80DTC P0112, P0113
MAP KPa
(Manifold
Absolute
Pressure)EngineKilopascals——General Description
DTC P0107, P0108
MILEngineOn/OffOffOffGeneral Description
AP (Accel
Position)EnginePercent08 14DTC P0121, P0122,
P0123
AP (Accel
Position)EngineVo l t s0.25 0.450.8 1.0DTC P0121, P0122,
P0123
Rail Oil
TemperatureEngineC (F)——DTC P0197, P0198
Desired Throttle
Motor PositionEngineSteps———
Learned Idle
Fuel QuantityEnginemm 3/st———

6E–56
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0107 (Flash DTC 34)
MAP Sensor Circuit Low Voltage
060RW134
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum).
The ECM monitors the MAP signals for voltages outside
the normal range of the MAP sensor. If the ECM detects a
MAP signal voltage that is excessively low, DTC P0107
will be set.
Action Taken When the DTC Sets
The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0107 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Turn on the ignition switch and stop the engine. At this
time, the boost pressure will be equal to the
atmospheric pressure and the signal voltage will
increase.
Check for intermittent codes.
The MAP sensor shares a ground with the ECT sensor,
and the Transmission Fluid Temperature sensor.
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
MAP display on the Tech 2 while moving connectors
and wiring harnesses related to the sensor. A change
in the display will indicate the location of the fault.
If DTC P0107 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0107 Diagnostic Chart may isolate
the cause of the fault.

6E–58
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0108 (Flash DTC 34)
MAP Sensor Circuit High Voltage
060RW134
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum).
The ECM monitors the MAP signals for voltages outside
the normal range of the MAP sensor. If the ECM detects a
MAP signal voltage that is excessively high, DTC P0108
will be set.
Action Taken When the DTC Sets
The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
DTC P0108 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:
Turn on the ignition switch and stop the engine. At this
time, the boost pressure will be equal to the
atmospheric pressure and the signal voltage will
increase.
Poor connection at ECM – Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
MAP display on the Tech 2 while moving connectors
and wiring harnesses related to the sensor. A change
in the display will indicate the location of the fault.
If DTC P0108 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set. If
it is determined that the DTC occurs intermittently.

6E–204
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Installation Procedure
1. Install the IAT sensor into the grommet in the intake
air duct.
035RW056
2. Correct the IAT electrical connector.
3. Connect the negative battery cable.
Manifold Absolute Pressure
(MAP) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the EGR valve.
035RW054
3. Disconnect the MAP sensor connector from the MAP
sensor.
035RW053
4.Remove the bolts and the MAP sensor from the
intake manifold.
035RW057

6E–214
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
6. Remove the fuel gauge unit.
Cover or plug the fuel tank to prevent dust, dirt, or
debris from entering the tank.
TS22911
Installation Procedure
1. Install the fuel gauge unit.
2. Install the fuel gauge unit retaining screws.
TS22911
3. Connect the wiring connector to the fuel gauge unit.
TS23771
4. Fill the fuel tank with fuel.
Tighten the fuel filler cap.
Check for leaks at the fuel gauge unit gasket.
5. Connect the negative battery cable.
Fuel Injectors
Removal and Installation Procedure
Refer to Engine Fuel in 4JX1 Engine Section.
Fuel Temperature Sensor
Removal Procedure
CAUTION: To reduce the risk of fire and personal
injury, it is necessary to relieve the fuel system
pressure before servicing the fuel system
components.
CAUTION: After relieving the system pressure, a
small amount of fuel may be released when servicing
fuel lines or connections. Reduce the chance of
personal injury by covering the fuel line fittings with
a shop towel before disconnecting the fittings. The
towels will absorb any fuel that may leak out. When
the disconnect is completed, place the towel in an
approved container.
1. Disconnect the negative battery cable.
2. Remove the intercooler assembly.
3. Remove the cylinder head. Refer to engine
mechanical section.