coolant temperature ISUZU AXIOM 2002 Service Owner's Manual

6E±4
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P1107 MAP Circuit Intermittent Low
Voltage 6E±386. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D T C P 1111 I AT Sensor Circuit Intermittent
High Voltage 6E±388. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1112 IAT Sensor Circuit Intermittent
Low Voltage 6E±391. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1114 ECT Sensor Circuit Intermittent
Low Voltage 6E±393. . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1115 ECT Sensor Circuit Intermittent
High Voltage 6E±395. . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code(DTC)P1120-TPS 1
Throttle Position Sensor (TPS1) Output
Abnormal 6E±398. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1125 ETC (Electric Throttle Control)
Limit Performance Mode 6E±401. . . . . . . . . . . . . . . . .
DTC P1133 HO2S Insufficient Switching
Bank 1 Sensor 1 6E±404. . . . . . . . . . . . . . . . . . . . . . . .
DTC P1134 HO2S Transition Time Ratio
Bank 1 Sensor 1 6E±408. . . . . . . . . . . . . . . . . . . . . . . .
DTC P1153 HO2S Insufficient Switching
Bank 2 Sensor 1 6E±412. . . . . . . . . . . . . . . . . . . . . . . .
DTC P1154 HO2S Circuit Transition Time
Ratio Bank 2 Sensor 1 6E±416. . . . . . . . . . . . . . . . . .
DTC P1167 Fuel System Rich During Decel
Fuel Cut Off (Bank 1) 6E±420. . . . . . . . . . . . . . . . . . . .
DTC P1169 Fuel System Rich During Decel
Fuel Cut Off (Bank 2) 6E±422. . . . . . . . . . . . . . . . . . . .
DTC P1171 Fuel System Lean During
Acceleration 6E±424. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1220 Throttle Position Senser2
(TPS2) Circuit Fault 6E±427. . . . . . . . . . . . . . . . . . . . .
DTC P1221 TPS1 ± TPS2 Correlation
(Circuit Performance) 6E±430. . . . . . . . . . . . . . . . . . .
DTC P1271 APS 1± 2 Correlation Error 6E±433. . .
DTC P1272 APS 2 ± 3 Correlation Error 6E±436. . .
DTC P1273 APS 1 ± 3 Correlation Error 6E±439. . . .
DTC P1275 APS 1 Output Fault 6E±442. . . . . . . . . . .
DTC P1280 APS 2 Output Fault 6E±444. . . . . . . . . . .
DTC P1285 APS 3 Output Fault 6E±446. . . . . . . . . . .
DTC P1290 ETC Forced Idle Mode 6E±448. . . . . . . .
DTC P1295 ETC Power Management Mode 6E±451
DTC P1299 ETC Forced Engine Shutdown
Mode 6E±455. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1310 ION Sensing Module Diagnosis 6E±459
DTC P1311 ION Sensing Module SEC
Line 1 Circuit Fault 6E±462. . . . . . . . . . . . . . . . . . . . . .
DTC P1312 ION Sensing Module SEC
Line 2 Circuit Fault 6E±465. . . . . . . . . . . . . . . . . . . . . .
DTC P1326 ION Sensing Module Combustion
Quality Input Circuit Fault 6E±468. . . . . . . . . . . . . . . .
DTC P1340 ION Sensing Module Cylinder ID
Fault (Cylinder Synchronization Fail) 6E±471. . . . . .
DTC P1404 EGR Stuck Closed 6E±474. . . . . . . . . . .
DTC P1441 EVAP System Flow During
Non-Purge 6E±477. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1514 TPS - MAF Correlation Error 6E±480. . . DTC P1515 Command - Actual TPS
Correlation Error 6E±484. . . . . . . . . . . . . . . . . . . . . . . .
DTC P1516 Command - Actual TPS
Correlation Error 6E±487. . . . . . . . . . . . . . . . . . . . . . . .
DTC P1523 Actuator Control Return
Performance 6E±490. . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1571 Brake Switch No Operation 6E±493. . . .
DTC P1625 PCM Unexpected Reset 6E±495. . . . . . .
DTC P1635 Reference Voltage # 1 Circuit
Fault 6E±496. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1639 Reference Voltage # 2 Circuit
Fault 6E±498. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1640 Driver-1-Output Circuit Fault
(ODM) 6E±500. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DTC P1650 Quad Driver Module ªAº Fault 6E±503. .
Symptom Diagnosis 6E±506. . . . . . . . . . . . . . . . . . . . .
Default Matrix Table 6E±535. . . . . . . . . . . . . . . . . . . . .
On Vehicle Service
Crankshaft Position (CKP) Sensor 6E±538. . . . . . . . .
Engine Coolant Temperature (ECT) Sensor 6E±538.
Heated Oxygen Sensor (HO2S) 6E±539. . . . . . . . . . .
Intake Air Temperature (IAT) Sensor 6E±542. . . . . . .
ION Sensing Module 6E±542. . . . . . . . . . . . . . . . . . . . .
Mass Air Flow (MAF) Sensor 6E±543. . . . . . . . . . . . .
Manifold Absolute Pressure (MAP) Sensor 6E±544.
Malfunction Indicator Lamp (MIL) 6E±545. . . . . . . . . .
Reduced Power Lamp 6E±545. . . . . . . . . . . . . . . . . . .
Powertrain Control Module (PCM) 6E±545. . . . . . . . .
Service Precaution 6E±545. . . . . . . . . . . . . . . . . . . .
EEPROM 6E±547. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Throttle Position (TP) Sensor 6E±547. . . . . . . . . . . . .
Vehicle Speed Sensor (VSS) 6E±548. . . . . . . . . . . . .
Air Cleaner/Air Filter 6E±549. . . . . . . . . . . . . . . . . . . . .
Common Chamber 6E±549. . . . . . . . . . . . . . . . . . . . . .
Accelerator Pedal Replacement 6E±550. . . . . . . . . . .
Accelerator Position Sensor Replacement 6E±551. .
Accelerator Position Sensor Adjustment 6E±551. . . .
Fuel Filler Cap 6E±552. . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Filter 6E±552. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Gauge Unit 6E±553. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Injectors 6E±554. . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Metering System 6E±555. . . . . . . . . . . . . . . . . . . .
Fuel Pump Assembly 6E±555. . . . . . . . . . . . . . . . . . . .
Fuel Pump Relay 6E±556. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Rail Assembly 6E±557. . . . . . . . . . . . . . . . . . . . . .
Fuel Tank 6E±558. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Throttle Body (TB) 6E±558. . . . . . . . . . . . . . . . . . . . . . .
Electronic Ignition System 6E±560. . . . . . . . . . . . . . . .
Catalytic Converter 6E±561. . . . . . . . . . . . . . . . . . . . . .
Air Conditioning Thermo Relay 6E±561. . . . . . . . . . .
EVAP Canister Hoses 6E±561. . . . . . . . . . . . . . . . . . . .
EVAP Canister 6E±562. . . . . . . . . . . . . . . . . . . . . . . . . .
EVAP Canister Vent Solenoid 6E±562. . . . . . . . . . . . .

6E±6
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Specifications
Tightening Specifications
ApplicationN´mLb Ft.Lb In.
EGR Bolt2518Ð
Engine Coolant Temperature Sensor3022Ð
Fuel Drain Plug2014Ð
Fuel Pressure Regulator Attaching Screw3Ð26
Fuel Rail Bolts2518Ð
Fuel Tank Undercover Retaining Bolts3627Ð
Heated Oxygen Sensor5540Ð
Lower Intake Manifold to Engine Block Bolts2518Ð
Lower Intake Manifold to Engine Block Nuts2518Ð
Spark Plugs1813Ð
Throttle Body Mounting Bolts10Ð87
Common Chamber to Lower Intake Manifold Bolts2518Ð
VSS Retaining Bolt1612Ð

6E±28
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Engine Component Locator Table
Number
NameLocation
1Linear Exhaust Gas Recirculation (EGR) ValveRear right side of the engine
2Throttle Position (TP) SensorOn the throttle body
3Intake Air Temperature (IAT) SensorOn the intake air duct near the throttle body
4Check Engine (MIL) LightOn the instrument panel beneath the
tachometer
5Positive Crankcase Ventilation (PCV) ValveOn the left of the cylinder head cover
6Air CleanerLeft front of the engine bay
7Mass Air Flow (MAF) SensorAttached to the air filter box
8Fuel RailOn the Common Chamber
9Fuel Pressure RegulatorRear side of the engine
10ION Sensing moduleBolted to the top of the Common Chamber
11Common ChamberTop of the engine
12EVAP Duty Solenoid ValveBolted to the front of the coolant pipe
13Fuse/Relay BoxAlong the inside of the right fender
14Manifold Absolute Pressure (MAP) SensorBolted to the top of the Common Chamber
15Throttle BodyBetween the intake air duct and the Common
Chamber
16Engine Coolant Temperature SensorOn the coolant crossover pipe at the front of
the engine, near the throttle body
17Power Train Control Module (PCM)Along the inside of the left fender

6E±35
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class 2 Serial Data Communications
Government regulations require that all vehicle
manufacturers establish a common communication
system. This vehicle utilizes the ªClass 2º communication
system. Each bit of information can have one of two
lengths: long or short. This allows vehicle wiring to be
reduced by transmitting and receiving multiple signals
over a single wire. The messages carried on Class 2 data
streams are also prioritized. If two messages attempt to
establish communications on the data line at the same
time, only the message with higher priority will continue.
The device with the lower priority message must wait.
The most significant result of this regulation is that it
provides Scan tool manufacturers with the capability to
access data from any make or model vehicle that is sold.
The data displayed on other Scan tools will appear the
same, with some exceptions. Some Scan tools will only
be able to display certain vehicle parameters as values
that are a coded representation of the true or actual value.
On this vehicle the Scan tool displays the actual values for
vehicle parameters. It will not be necessary to perform
any conversions from coded values to actual values.
On-Board Diagnostic (OBD II)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The diagnostic test has passed during the current
ignition cycle.

The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The fault identified by the diagnostic test is currently
active.

The fault has been active during this ignition cycle.

The operating conditions at the time of the failure.Remember, a fuel trim DTC may be triggered by a list of
vehicle faults. Make use of all information available (other
DTCs stored, rich or lean condition, etc.) when
diagnosing a fuel trim fault.
Comprehensive Component Monitor
Diagnostic Operation
Comprehensive component monitoring diagnostics are
required to monitor emissions-related input and output
powertrain components. The
CARB OBD II
Comprehensive Component Monitoring List Of
Components Intended To illuminate MIL
is a list of
components, features or functions that could fall under
this requirement.
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable, i.e.
Throttle Position (TP) sensor that indicates high throttle
position at low engine loads or MAP voltage. Input
components may include, but are not limited to the
following sensors:

Vehicle Speed Sensor (VSS)

Crankshaft Position (CKP) sensor

Throttle Position (TP) sensor

Engine Coolant Temperature (ECT) sensor

Manifold Absolute Pressure (MAP) sensor

Mass Air Flow (MAF) sensor
In addition to the circuit continuity and rationality check,
the ECT sensor is monitored for its ability to achieve a
steady state temperature to enable closed loop fuel
control.
Output Components:
Output components are diagnosed for proper response to
control module commands. Components where
functional monitoring is not feasible will be monitored for
circuit continuity and out-of-range values if applicable.
Output components to be monitored include, but are not
limited to, the following circuits:

Control module controlled EVAP Canister Purge
Valve

Electronic Transmission controls

A/C relays

VSS output

MIL control

Cruise control inhibit
Refer to PCM and Sensors in General Descriptions.
Passive and Active Diagnostic Tests
A passive test is a diagnostic test which simply monitors a
vehicle system or component. Conversely, an active test,
actually takes some sort of action when performing
diagnostic functions, often in response to a failed passive
test. For example, the EGR diagnostic active test will
force the EGR valve open during closed throttle decel
and/or force the EGR valve closed during a steady state.
Either action should result in a change in manifold
pressure.

6E±38
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Does not store a Freeze Frame

Stores Fail Record when test fails

Updates the Fail Record each time the diagnostic
test fails

Type D

Non-Emissions related

Not request illumination of any lamp

Stores a History DTC on the
first trip with a fail


Does not store a Freeze Frame

Stores Fail Record when test fails

Updates the Fail Record each time the diagnostic
test fails
IMPORTANT:Only four Fail Records can be stored.
Each Fail Record is for a different DTC. It is possible that
there will not be Fail Records for every DTC if multiple
DTCs are set.
Special Cases of Type B Diagnostic Tests
Unique to the misfire diagnostic, the Diagnostic Executive
has the capability of alerting the vehicle operator to
potentially damaging levels of misfire. If a misfire
condition exists that could potentially damage the
catalytic converter as a result of high misfire levels, the
Diagnostic Executive will command the MIL to ªflashº at a
rate of once per second during those the time that the
catalyst damaging misfire condition is present.
Fuel trim and misfire are special cases of
Type B
diagnostics. Each time a fuel trim or misfire malfunction is
detected, engine load, engine speed, and engine coolant
temperature are recorded.
When the ignition is turned off, the last reported set of
conditions remain stored. During subsequent ignition
cycles, the stored conditions are used as reference for
similar conditions. If a malfunction occurs during two
consecutive trips, the Diagnostic Executive treats the
failure as a normal
Type B diagnostic, and does not use
the stored conditions. However, if a malfunction occurs
on two non-consecutive trips, the stored conditions are
compared with the current conditions. The MIL will then
illuminate under the following conditions:

When the engine load conditions are within 10% of
the previous test that failed.

Engine speed is within 375 rpm, of the previous test
that failed.

Engine coolant temperature is in the same range as
the previous test that failed.Storing and Erasing Freeze Frame Data and Failure
Records
Government regulations require that engine operating
conditions be captured whenever the MIL is illuminated.
The data captured is called Freeze Frame data. The
Freeze Frame data is very similar to a single record of
operating conditions. Whenever the MIL is illuminated,
the corresponding record of operating conditions is
recorded to the Freeze Frame buffer.
Freeze Frame data can only be overwritten with data
associated with a misfire or fuel trim malfunction. Data
from these faults take precedence over data associated
with any other fault. The Freeze Frame data will not be
erased unless the associated history DTC is cleared.
Each time a diagnostic test reports a failure, the current
engine operating conditions are recorded in the
Failure
Records
buffer. A subsequent failure will update the
recorded operating conditions. The following operating
conditions for the diagnostic test which failed
typically
include the following parameters:

Air Fuel Ratio

Air Flow Rate

Fuel Trim

Engine Speed

Engine Load

Engine Coolant Temperature

Vehicle Speed

TP Angle

AP Angle

MAP/BARO

Injector Base Pulse Width

Loop Status
Intermittent Malfunction Indicator Lamp
In the case of an ªintermittentº fault, the MIL (ªCheck
Engineº lamp) may illuminate and then (after three trips)
go ªOFFº. However, the corresponding diagnostic trouble
code will be stored in memory. When unexpected
diagnostic trouble codes appear, check for an intermittent
malfunction.
A diagnostic trouble code may reset. Consult the
ªDiagnostic Aidsº associated with the diagnostic trouble
code. A physical inspection of the applicable sub-system
most often will resolve the problem.
Data Link Connector (DLC)
The provision for communication with the control module
is the Data Link Connector (DLC). It is located at the
lower left of the instrument panel behind a small square
cover. The DLC is used to connect to the Tech 2 Scan
Tool. Some common uses of the Tech 2 are listed below:

6E±63
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
A/C Clutch Control Circuit Diagnosis
060R100063
Circuit Description
When air conditioning and blower fan are selected, and if
the system has a sufficient refrigerant charge, a 12-volt
signal is supplied to the A/C request input of the
powertrain control module (PCM). The A/C request
signal may be temporarily canceled during system
operation by the electronic thermostat in the evaporator
case. When the A/C request signal is received by the
PCM, the PCM supplies a ground from the compressor
clutch relay if the engine operating conditions are within
acceptable ranges. With the A/C compressor relay
energized, voltage is supplied to the compressor clutch
coil.
The PCM will enable the compressor clutch to engage
whenever A/C has been selected with the engine running,
unless any of the following conditions are present:

The throttle is greater than 90%.

The ignition voltage is below 10.5 volts.

The engine speed is greater than 4500 RPM for 5
seconds or 5400 RPM.
The engine coolant temperature (ECT) is greater
than 125
C (257
F).

The intake air temperature (IAT) is less than 5
C
(41
F).

The power steering pressure switch signals a high
pressure condition.
Diagnostic Aids
To diagnose an the intermittent fault, check for following
conditions:

Poor connection at the PCM±Inspect connections 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 OK, observe the
A/C clutch while moving connectors and wiring
harnesses related to the A/C. A sudden clutch
malfunction will indicate the source of the intermittent
fault.

6E±64
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
A/C Clutch Diagnosis
This chart should be used for diagnosing the electrical
portion of the A/C compressor clutch circuit. A Tech 2 will
be used in diagnosing the system. The Tech 2 has the
ability to read the A/C request input to the PCM. The
Tech 2 can display when the PCM has commanded the
A/C clutch ªONº. The Tech 2 should have the ability to
override the A/C request signal and energize the A/C
compressor relay.
Test Description
IMPORTANT:Do not engage the A/C compressor
clutch with the engine running if an A/C mode is not
selected at the A/C control switch.
The numbers below refer to the step numbers on the
Diagnostic Chart:3. This a test determine is the problem is with the
refrigerant system. If the switch is open, A/C
pressure gauges will be used to determine if the
pressure switch is faulty or if the system is partially
discharged or empty.
4. Although the normal complaint will be the A/C clutch
failing to engage, it is possible for a short circuit to
cause the clutch to run when A/C has not been
selected. This step is a test for that condition.
7. There is an extremely low probability that both relays
will fail at the same time, so the substitution process
is one way to check the A/C Thermostat relay. Use
a known good relay to do a substitution check.
A/C Clutch Control Circuit Diagnosis

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Are any other DTCs stored?
Ð
Go to the
other DTC
chart(s) first
Go to Step 3
31. Disconnect the electrical connector at the pressure
switch located on the receiver/drier.
2. Use an ohmmeter to check continuity across the
pressure switch.
Is the pressure switch open?
Ð
Go to Air
Conditioning
to diagnose
the cause of
the open
pressure
switch
Go to Step 4
4IMPORTANT:Before continuing with the diagnosis, the
following conditions must be met:

The intake air temperature must be greater than
15
C. (60
F).

The engine coolant temperature must be less
than 119
C (246
F).
1. A/C ªOFFº.
2. Start the engine and idle for 1 minute.
3. Observe the A/C compressor.
Is the A/C compressor clutch engaged even though
A/C has not been requested?
ÐGo to Step 37Go to Step 5
51. Idle the engine.
2. A/C ªONº.
3. Blower ªONº.
4. Observe the A/C compressor.
Is the A/C compressor magnetic clutch engaged?
Ð
Refer to
Diagnostic
Aids
Go to Step 6
61. Engine idling.
2. A/C ªONº.
3. Blower ªONº.
4. Observe the ªA/C Requestº display on the Tech 2.
(Refer to the Miscellaneous test)
Does the tool ªA/C Requestº display indicate ªYesº?
ÐGo to Step 26Go to Step 7

6E±70
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Injector Coil Test Procedure (Steps 1-6) and Injector Balance Test Procedure
(Steps 7-11)

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Turn the engine ªOFFº.
NOTE: In order to prevent flooding of a single cylinder
and possible engine damage, relieve the fuel pressure
before performing the fuel injector coil test procedure.
2. Relieve the fuel pressure. Refer to
Test Description
Number 2.
3. Connect the J 39021-5V Fuel Injector Tester to B+
and ground, and to the J 39021-90 Injector Switch
Box.
4. Connect the injector switch box to the grey fuel
injector harness connector located on the front of
the EVAP canister bracket.
5. Set the amperage supply selector switch on the fuel
injector tester to the ªCoil Testº 0.5 amp position.
6. Connect the leads from the J 39200 Digital
Voltmeter (DVM) to the injector tester. Refer to the
illustrations associated with the test description.
7. Set the DVM to the tenths scale (0.0).
8. Observe the engine coolant temperature.
Is the engine coolant temperature within the specified
values?
10
C (50
F)
to 35
C
(95
F)
Go to Step 3Go to Step 5
31. Set injector switch box injector #1.
2. Press the ªPush to Start Testº button on the fuel
injector tester.
3. Observe the voltage reading on the DVM.
IMPORTANT:The voltage reading may rise during the
test.
4. Record the lowest voltage observed after the first
second of the test.
5. Set the injector switch box to the next injector and
repeat steps 2, 3, and 4.
Did any fuel injector have an erratic voltage reading
(large fluctuations in voltage that did not stabilize) or a
voltage reading outside of the specified values?
5.7-6.6 VGo to Step 4Go to Step 7
4Replace the faulty fuel injector(s). Refer to Fuel
Injector.
Is the action complete?ÐGo to Step 7Ð

6E±73
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Powertrain Control Module (PCM)
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 PCM memory.
Diagnostic trouble codes can also be cleared by turning
the ignition ªOFFº and disconnecting the battery power
from the PCM for 30 seconds. Turning off the ignition and
disconnecting the battery power from the PCM will cause
all diagnostic information in the PCM memory to be
cleared. Therefore, all the diagnostic tests will have to be
re-run.
Since the PCM 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 PCM connections
or the PCM is the cause of a problem, and the PCM is
replaced, but this does not correct the problem, one of the
following may be the reason:

There is a problem with the PCM terminal
connections. The terminals may have to be removed
from the connector in order to check them properly.

EEPROM program is not correct for the application.
Incorrect components or reprogramming the PCM
with the wrong EEPROM program may cause a
malfunction and may or may not set a DTC.

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 component and wiring associated with the
affected system.

There is a shorted solenoid, relay coil, or harness.
Solenoids and relays are turned ªONº and ªOFFº by
the PCM using internal electronic switches called
drivers. A shorted solenoid, relay coil, or harness will
not damage the PCM but will cause the solenoid or
relay to be inoperative.
Multiple PCM Information Sensor
DTCs Set
Circuit Description
The powertrain control module (PCM) monitors various
sensors to determine the engine operating conditions.
The PCM controls fuel delivery, spark advance,
transmission operation, and emission control device
operation based on the sensor inputs.
The PCM provides a sensor ground to all of the sensors.
The PCM 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 engine coolant temperature (ECT) sensor

The intake air temperature (IAT) sensor

The transmission fluid temperature (TFT) sensorThe PCM provides the following sensors with a 5±volt
reference and a sensor ground signal:
1

The exhaust gas recirculating (EGR) pintle position
sensor

The manifold absolute pressure (MAP) sensor

The throttle position (TP) sensor 1

The acceleration position (AP) sensor 1

The acceleration position (AP) sensor 3

The Vapor Pressure Sensor
2

The Crank position (CKP) sensor

The throttle position (TP) sensor 2

The acceleration position (AP) sensor 2
The PCM monitors the separate feedback signals from
these sensors in order to determine their operating
status.
Diagnostic Aids
IMPORTANT:Be sure to inspect PCM 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:

P0425

P0108, P1106

P0406

P1120, P1515, P1221, P1516, P1635

P1275, P1639, P1271, P1273

P1285, P1272, P1273

P0336, P0337

P1220, P1515, P1221, P1515, P1516

P1280, P1271, P1272
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 PCM
and the splice will cause one or more of the following
DTCs to be set:

P0425

P0108, P1106

P0406

P1120, P1515, P1221, P1516, P1635

P1275, P1639, P1271, P1273

P1285, P1272, P1273

P0336, P0337

P1220, P1515, P1221, P1515, P1516

P1280, P1271, P1272
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:

P0453

P0106, P0107, P1107

P0401, P1404, P0405

P1120, P1515, P1221, P1516, P1635

6E±76
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Exhaust Gas Recirculation (EGR)
Diagnosis
An EGR flow check diagnosis of the linear EGR system is
covered by DTC P0401. Pintle position error diagnosis is
covered by DTC P0402, P0404, P1404, P0405, P0406. If
EGR diagnostic trouble codes P0401 and/or P0402,
P0404, P1404, P0405, P0406 are encountered, refer to
the DTC charts.
Engine Tech 2 Data Definitions and
Ranges
A/C CLUTCH ± Tech 2 Displays ON or OFF ±
Indicates whether the PCM has commanded the A/C
clutch ON. Used in A/C system diagnostic.
A/C REQUEST Ð Tech 2 Displays YES or NO Ð
Indicates the state of the A/C request input circuit from the
HVAC controls. The PCM uses the A/C request signal to
determine whether A/C compressor operation is being
requested.
AIR/FUEL RATIO Ð Tech 2 Range 0.0-25.5 Ð
Air/fuel ratio indicates the PCM commanded value. In
closed loop, the air/fuel ratio should normally be
displayed around ª14.2-14.7º. A lower air/fuel ratio
indicates a richer commanded mixture, which may be
seen during power enrichment or TWC protection modes.
A higher air/fuel ratio indicates a leaner commanded
mixture. This can be seen during deceleration fuel mode.
AP1 ÐTech 2 Range 0%-100% Ð
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
ª13%º at idle and ª85-89%º at wide open throttle.
AP2 ÐTech 2 Range 0%-100% Ð
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
ª85-89%º at idle and ª11-15%º at wide open throttle.
AP3 ÐTech 2 Range 0%-100% Ð
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
ª85-89%º at idle and ª32-36%º at wide open throttle.
BAROMETRIC PRESSURE Ð Tech 2 Range 10-105
kPa/0.00-5.00 Volts Ð
The barometric pressure reading is determined from the
MAP sensor signal monitored during key up and wide
open throttle (WOT) conditions. The barometric pressure
is used to compensate for altitude differences and is
normally displayed around ª61-104º depending on
altitude and barometric pressure.
CHECK TRANS LAMP Ð AUTO TRANSMISSION Ð
Indicates the need to check for a DTC with the Tech 2
when the lamp is flashing 0.2 seconds ON and 0.2
seconds OFF.
DESIRED EGR POS. Ð Tech 2 Range 0%-100% Ð
Represents the EGR pintle position that the PCM is
commanding.
DESIRED IDLE Ð Tech 2 Range 0-3187 RPM Ð
The idle speed that the PCM is commanding. The PCM
will compensate for various engine loads based on engine
coolant temperature, to keep the engine at the desired
speed.ECT Ð (Engine Coolant Temperature) Tech 2
Range ±40
C to 151
C (±40
F to 304
F) Ð
The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the PCM. The PCM 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 PCM
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 PCM will interpret
the lower voltage as a warm engine.
EGR DUTY CYCLE Ð Tech 2 Range 0%-100% Ð
Represents the EGR valve driver PWM signal from the
PCM. A duty cycle of 0% indicates that no EGR flow is
being commanded; a 100% duty cycle indicates
maximum EGR flow commanded.
EGR FEEDBACK Ð Tech 2 Range 0.00-5.00 Volts Ð
Indicates the EGR pintle position sensor signal voltage
being monitored by the PCM. A low voltage indicates a
fully extended pintle (closed valve); a voltage near 5 volts
indicates a retracted pintle (open valve).
ENGINE LOAD Ð Tech 2 Range 0%-100% Ð
Engine load is calculated by the PCM from engine speed
and MAF sensor readings. Engine load should increase
with an increase in RPM or air flow.
ENGINE RUN TIME Ð Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec Ð
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 Ð Range 0-9999 RPM Ð
Engine speed is computed by the PCM from the 58X
reference input. It should remain close to desired idle
under various engine loads with engine idling.
EVAP PURGE PWM Ð Tech 2 Range 0%-100% Ð
Represents the PCM commanded PWM duty cycle of the
EVAP purge solenoid valve. ª0%º displayed indicates no
purge; ª100%º displayed indicates full purge.
FUEL PUMP Ð Tech 2 Displays ON or OFF Ð
Indicates the PCM commanded state of the fuel pump
relay driver circuit.
HO2S BANK 1, SEN. 1
Ð Tech 2 Range 0-1132 mV Ð
Represents the fuel control exhaust oxygen sensor
output voltage. Should fluctuate constantly within a range
between 10 mV (lean exhaust) and 1000 mV (rich
exhaust) while operating in closed loop.
HO2S BANK 1, SEN. 2
Ð Tech 2 Range 0-1000mV Ð
Monitors the exhaust oxygen sensor output voltage. The
PCM monitors the operating efficiency of catalytic
converter by comparing the output voltages of sensor 1
and sensor 2 in this bank. If the catalytic converter is
operating efficiently, the output voltage of sensor 1 will
give a greater fluctuation than that of sensor 2. If the
PCM detects an abnormal level of voltage fluctuation
from sensor 2, a DTC P0420 will be set, indicating that the
catalytic converter for this bank is no longer operating
efficiently.