
6E–90
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1195 (Flash DTC 61)
Rail Pressure System High Voltage
060RW134
Circuit Description
The rail pressure (RP) sensor responds to changes in oil
rail pressure.
The ECM monitors the RP signals for voltages outside the
normal range of the RP sensor. If the ECM detects a RP
signal voltage that is excessively low, DTC P1195 will be
set.
Action Taken When the DTC Sets
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 P1195 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:
Check for intermittent codes.
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 P1195 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 P1195 Diagnostic Chart may isolate
the cause of the fault.

6E–93 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Circuit Description
The rail pressure control valve (RPCV) is built in the high
pressure oil circuit.
RPCV is an important device which is used to control oil
pressure in the HEUI system.
The circuit receives current through Engine 15A fuse from
the battery, current flowing in the order of RPCV.
Action Taken When the DTC Sets
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 P1196 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:
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
Rail Pressure Control display on the Tech 2 while
moving connectors and wiring harnesses related to the
Rail Pressure Control. A change in the Rail Pressure
Control display will indicate the location of the fault.
If DTC P1196 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.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is present.
DTC P1196 – RP System High Warning
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Engine is running.
2. Observe the “Rail Pressure Control” display on the
Te c h 2 .
Is the action correct?
—Go to Step 4Go to Step 3
3Replace the RPCV.
Is the action complete?
—Verify repairGo to Step 4
41. Engine is running.
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor “ DTC” info for DTC P1196.
Does the Tech 2 indicate DTC P1196 failed this
ignition?
—Go to Step 5—
51. Check the 2 way valve.
2. Observe the “RP Control” display on the Tech 2.
Is the action correct?
—Go to Step 4Go to Step 6
6Replace the 2 way valve.
Is the action complete?
—Verify repair—

6E–94
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0197 (Flash DTC 16)
Oil Temp Sensor Low Voltage
060RW129
Circuit Description
The engine oil temperature (OT) sensor is a thermistor
mounted in the oil rail. The Engine Control Module ECM
applies a voltage (about 5 volts) through a pull-up resistor
to the ECT signal circuit. When the engine oil is cold, the
sensor (thermistor) resistance is high, therefore the ECM
will measure a high signal voltage. As the engine oil
warms, the sensor resistance becomes lower, and the OT
signal voltage measured at the ECM drops.
Action Taken When the DTC Sets
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 P0197 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:
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
OT display on the Tech 2 while moving connectors and
wiring harnesses related to the OT sensor. A change
in the OT display will indicate the location of the fault.
If DTC P0197 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–95 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is present.
3. If DTC P0197 can be repeated only by duplicating
the Failure Records conditions, refer to the
“Temperature vs. Resistance Values” table. The
table may be used to test the OT sensor at various
temperatures to evaluate the possibility of a
“shifted” sensor that may be shorted above or below
a certain temperature. If this is the case, replace
the OT sensor. If the OT sensor appears to be OK,
the fault is intermittent; refer to
Diagnostic Aids.
Engine Oil Temperature Sensor
CFOhms
Temperature vs. Resistance Values
(approximate)
80176332
25772796
15594450
DTC P0197 – OT Sensor Low Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF.”
2. Observe the “Eng Oil Temp” display on the Tech 2.
Is the “Eng Oil Temp” below the specified value?
139C
(282
F)Go to Step 4Go to Step 3
31. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor “ DTC” info for DTC P0197.
Does the Tech 2 indicate DTC P0197 failed this
ignition?
—Go to Step 4
Refer to
Diagnostic
Aids
41. Disconnect the OT sensor electrical connector.
2. Observe the “Eng Oil Temp” display on the Tech 2.
Is the “Eng Oil Temp” at the specified value?
–39C
(–38
F)Go to Step 6Go to Step 5
51. Ignition “OFF.”
2. Disconnect the ECM and check the OT signal circuit
for a short to ground or a short to the sensor ground
circuit.
3. If the OT signal circuit is shorted. repair it as
necessary.
Was the OT signal circuit shorted to ground?
—Verify repairGo to Step 7
6Replace the OT sensor.
Is the action complete?
—Verify repair—
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—Verify repair—

6E–96
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0198 (Flash DTC 16)
Oil Temp Sensor High Voltage
060RW129
Circuit Description
The engine oil temperature (OT) sensor is a thermistor
mounted in the oil rail. The Engine Control Module ECM
applies a voltage (about 5 volts) through a pull-up resistor
to the ECT signal circuit. When the engine oil is cold, the
sensor (thermistor) resistance is high, therefore the ECM
will measure a high signal voltage. As the engine oil
warms, the sensor resistance becomes lower, and the OT
signal voltage measured at the ECM drops.
Action Taken When the DTC Sets
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 P0198 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:
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
OT display on the Tech 2 while moving connectors and
wiring harnesses related to the OT sensor. A change
in the OT display will indicate the location of the fault.
If DTC P0198 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–194
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Lubrication System Trouble
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
In road tests oil pressure doesn’t rise, or oil is foul to
excess.
Was OBD System check performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin research.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found?
—Verify repairGo to Step 3
31. Check if a correct engine oil is used.
2. If a problem is found, change engine oil.
Was a problem found?
—Verify repairGo to Step 4
41. Check the oil pressure meter for damage.
2. Check the oil unit harness and connector for
damage.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 5
51. Check oil pipe connections for leakage.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 6
61. Check oil filter for clogging.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
71. Check valve clearance.
2. If a problem is found, adjust as necessary.
Was a problem found?
—Verify repairGo to Step 8
81. Check camshaft bearing for wear.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 9
91. Check crankshaft & connecting rod bearings for
wear.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 10
101. Check oil pump for damage.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 11

6E–198
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Excess Engine Oil Consumption
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Oil consumption measured in road tests is higher than
expected.
Was OBD System check performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin research.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found?
—Verify repairGo to Step 3
31. Check if a correct engine oil is used.
2. If a problem is found, change engine oil.
Was a problem found?
—Verify repairGo to Step 4
41. Check oil pipe connections for leakage.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 5
51. Check oil seals and gaskets for leakage.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 6
61. Connect Tech 2 to the vehicle.
2. Perform RPCV test to check its function.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 7
71. Check piston ring for damage & groove wear.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
81. Check valve stem, valve guide and oil controller for
wear.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 9
91. Check camshaft carrier & cylinder head gaskets for
blow-by.
2. If a problem is found, repair or replace as
necessary.
Was a problem found?
—Verify repairGo to Step 10
101. Review all the diagnostic procedures in this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:
Visual/physical check
Tech 2 data list
Freeze Frame data
All electrical connections in suspected circuits
& systems
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repair
Contact
Te c h n i c a l
Assistance

6E–226
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
0018
Manifold Absolute Pressure (MAP) Sensor
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure. The MAP sensor
signal voltage to the ECM varies from below 2 volts at idle
(high vacuum) to above 4 volts.
The MAP sensor is used to determine the following:
Boost pressure for injector control.
Barometric pressure (BARO).
If the ECM detects a voltage that is lower than the
possible range of the MAP sensor, DTC P0107 will be set.
A signal voltage higher than the possible range of the
sensor will set DTC P0108. An intermittent low or high
voltage will set DTC P1107 or DTC P1106, respectively.
The ECM can detect a shifted MAP sensor. The ECM
compares the MAP sensor signal to a calculated MAP
based on throttle position and various engine load factors.
If the ECM detects a MAP signal that varies excessively
above or below the calculated value, DTC P0106 will set.
Engine Control Module (ECM)
The engine control module (ECM) is located in the engine
room.
The ECM constantly observes the information from
various sensors. The ECM controls the systems that
affect vehicle performance. The ECM performs the
diagnostic function of the system. It can recognize
operational problems, alert the driver through the MIL
(Service Engine Soon lamp), and store diagnostic trouble
codes (DTCs). DTCs identify the problem areas to aid the
technician in making repairs.
ECM Function
The ECM supplies 5, 12 and 110 volts to power various
sensors or switches. The power is supplied through
resistances in the ECM which are so high in value that a
test light will not light when connected to the circuit. In
some cases, even an ordinary shop voltmeter will not give
an accurate reading because its resistance is too low.
Therefore, a digital voltmeter with at least 10 megohms
input impedance is required to ensure accurate voltage
readings. The ECM controls output circuits such as theinjectors, glow relays, etc., by controlling the ground or
the power feed circuit through transistors or through
either of the following two devices:
Output Driver Module (ODM)
Quad Driver Module (QDM)
ECM Components
The ECM is designed to maintain exhaust emission levels
to government mandated standards while providing
excellent driveability and fuel efficiency. The ECM
monitors numerous engine and vehicle functions via
electronic sensors such as the crankshaft position (CKP)
sensor, and vehicle speed sensor (VSS). The ECM also
controls certain engine operations through the following:
Fuel injector control
Rail pressure control
ECM Voltage Description
The ECM supplies a buffered voltage to various switches
and sensors. It can do this because resistance in the
ECM is so high in value that a test light may not illuminate
when connected to the circuit. An ordinary shop
voltmeter may not give an accurate reading because the
voltmeter input impedance is too low. Use a 10-megohm
input impedance digital voltmeter to assure accurate
voltage readings.
The input/output devices in the ECM include
analog-to-digital converters, signal buffers, counters,
and special drivers. The ECM controls most components
with electronic switches which complete a ground circuit
when turned “ON.” These switches are arranged in
groups of 4 and 7, called either a surface-mounted quad
driver module (QDM), which can independently control up
to 4 output terminals, or QDMs which can independently
control up to 7 outputs. Not all outputs are always used.
ECM Input/Outputs
Inputs – Operating Conditions Read
Air Conditioning “ON” or “OFF”
Engine Coolant Temperature
Crankshaft Position
Electronic Ignition
Manifold Absolute Pressure
Battery Voltage
Intake Throttle Position
Vehicle Speed
Fuel Temperature
Oil Temperature
Intake Air Temperature
EGR boost pressure
Oil rail pressure
Camshaft Position
Accelerator position
Outputs – Systems Controlled
Exhaust Gas Recirculation (EGR)
Injector Control
QWS