
PCV VALVE
DESCRIPTION
The PCV valve contains a spring loaded plunger.
The plunger meters the amount of crankcase vapors
routed into the combustion chamber based on intake
manifold vacuum.
OPERATION
When the engine is not operating or during an
engine backfire, the spring forces the plunger back
against the seat. This prevents vapors from flowing
through the valve (Fig. 8).
When the engine is at idle or cruising, high mani-
fold vacuum is present. At these times manifold vac-
uum is able to completely compress the spring and
pull the plunger to the top of the valve (Fig. 9). In
this position there is minimal vapor flow through the
valve.During periods of moderate intake manifold vac-
uum the plunger is only pulled part way back from
the inlet. This results in maximum vapor flow
through the valve (Fig. 10).
DIAGNOSIS AND TESTING - PCV SYSTEM
INSPECTION
WARNING: APPLY PARKING BRAKE AND/OR
BLOCK WHEELS BEFORE PERFORMING ANY TEST
OR ADJUSTMENT WITH THE ENGINE OPERATING.
(1) With engine idling, remove the hose from the
PCV valve. If the valve is not plugged, a hissing
noise will be heard as air passes through the valve. A
strong vacuum should also be felt when a finger is
placed over the valve inlet.
(2) Install hose on PCV valve. Remove the
make-up air hose from the air plenum at the rear of
the engine. Hold a piece of stiff paper (parts tag)
loosely over the end of the make-up air hose.
(3)
After allowing approximately one minute for
crankcase pressure to reduce, the paper should draw up
against the hose with noticeable force. If the engine
does not draw the paper against the grommet after
installing a new valve, replace the PCV valve hose.
(4)Turn the engine off. Remove the PCV valve from
intake manifold. The valve should rattle when shaken.
(5) Replace the PCV valve and retest the system if
it does not operate as described in the preceding
tests.Do not attempt to clean the old PCV valve.
If the valve rattles, apply a light coating of Loctitet
Pipe Sealant With Teflon to the threads. Thread the
PCV valve into the manifold plenum and tighten to 7
N´m (60 in. lbs.) torque.
Fig. 7 PCV VALVE 2.4L
1 - PCV Valve
Fig. 8 Engine Off or Engine Backfire No Vapor Flow
Fig. 9 High Intake Manifold Vacuum Minimal Vapor
Flow
Fig. 10 Moderate Intake Manifold Vacuum Maximum
Vapor Flow
RSEVAPORATIVE EMISSIONS25-17

SYMPTOM DIAGNOSTIC TEST
POOR FUEL ECONOMY CHECKING PCM POWER AND GND CKT
CHECKING THE FUEL PRESSURE
CHECKING ECT SENSOR
CHECKING THROTTLE POSITION SENSOR
CHECKING MAP SENSOR
CHECKING IDLE AIR CONTROL MOTOR OPERATION
CHECKING IAT SENSOR
3.4 USING THE DRBIIIT
Refer to the DRBIIItuser 's guide for instructions
and assistance with reading DTC's, erasing DTC's,
and other DRBIIItfunctions.
3.5 DRBIIITERROR MESSAGES AND
BLANK SCREEN
Under normal operation, the DRBIIItwill dis-
play one of only two error messages:
± User-Requested WARM Boot or User-
Requested COLD Boot
ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548
err: 0x1
User-Requested COLD Boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.5.1 DRBIIITDOES NOT POWER UP
If the LED's do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage (data link
connector cavity 16). A minimum of 11 volts is
required to adequately power the DRBIIIt.
If all connections are proper between the
DRBIIItand the vehicle or other devices, and the
vehicle battery is fully charged, and inoperative
DRBIIItmay be the result of faulty cable or vehicle
wiring.
3.5.2 DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition
4.0 DISCLAIMERS, SAFETY,
WARNINGS
4.1 DISCLAIMERS
All information, illustrations, and specifications
contained in this manual are based on the latest
information available at the time of publication.
The right is reserved to make changes at any time
without notice.
4.2 SAFETY
4.2.1 TECHNICIAN SAFETY INFORMATION
WARNING: ENGINES PRODUCE CARBON
MONOXIDE THAT IS ODORLESS, CAUSES
SLOWER REACTION TIME, AND CAN LEAD
TO SERIOUS INJURY. WHEN THE ENGINE IS
OPERATING, KEEP SERVICE AREAS WELL
VENTILATED OR ATTACH THE VEHICLE
EXHAUST SYSTEM TO THE SHOP EXHAUST
REMOVAL SYSTEM.
Set the parking brake and block the wheels before
testing or repairing the vehicle. It is especially
10
GENERAL INFORMATION

important to block the wheels on front-wheel drive
vehicles; the parking brake does not hold the drive
wheels.
When servicing a vehicle, always wear eye pro-
tection, and remove any metal jewelry such as
watchbands or bracelets that might make an inad-
vertent electrical contact.
When diagnosing a powertrain system problem,
it is important to follow approved procedures where
applicable. These procedures can be found in ser-
vice manual procedures. Following these proce-
dures is very important to the safety of individuals
performing diagnostic tests.
4.2.2 VEHICLE PREPARATION FOR
TESTING
Make sure the vehicle being tested has a fully
charged battery. If it does not, false diagnostic codes
or error messages may occur.
4.2.3 SERVICING SUB ASSEMBLIES
Some components of the powertrain system are
intended to be serviced in assembly only. Attempt-
ing to remove or repair certain system sub-
components may result in personal injury and/or
improper system operation. Only those components
with approved repair and installation procedures in
the service manual should be serviced.
4.2.4 DRBIIITSAFETY INFORMATION
WARNING: EXCEEDING THE LIMITS OF THE
DRB MULTIMETER IS DANGEROUS. IT CAN
EXPOSE YOU TO SERIOUS INJURY.
CAREFULLY READ AND UNDERSTAND THE
CAUTIONS AND THE SPECIFICATION
LIMITS.
Follow the vehicle manufacturer 's service specifi-
cations at all times.
²Do not use the DRB if it has been damaged.
²Do not use the test leads if the insulation is
damaged or if metal is exposed.
²To avoid electrical shock, do not touch the test
leads, tips, or the circuit being tested.
²Choose the proper range and function for the
measurement. Do not try voltage or current mea-
surements that may exceed the rated capacity.
²Do not exceed the limits shown in the table below:
FUNCTION INPUT LIMIT
Volts 0 - 500 peak volts AC
0 - 500 volts DC
Ohms (resistance)* 0 - 1.12 megohms
FUNCTION INPUT LIMIT
Frequency Measured
Frequency Generated0-10kHz
Temperature -58 - 1100ÉF
-50 - 600ÉC
* Ohms cannot be measured if voltage is present.
Ohms can be measured only in a non-powered
circuit.
²Voltage between any terminal and ground must
not exceed 500v DC or 500v peak AC.
²Use caution when measuring voltage above 25v
DC or 25v AC.
²The circuit being tested must be protected by a
10A fuse or circuit breaker.
²Use the low current shunt to measure circuits up
to 10A. Use the high current clamp to measure
circuits exceeding 10A.
²When testing for the presence of voltage or cur-
rent, make sure the meter is functioning cor-
rectly. Take a reading of a known voltage or
current before accepting a zero reading.
²When measuring current, connect the meter in
series with the load.
²Disconnect the live test lead before disconnecting
the common test lead.
²When using the meter function, keep the DRBIIIt
away from spark plug or coil wires to avoid mea-
suring error from outside interference.
4.3 WARNINGS AND CAUTIONS
4.3.1 ROAD TEST WARNINGS
Some complaints will require a test drive as part
of the repair verification procedure. The purpose of
the test drive is to try to duplicate the diagnostic
code or symptom condition.
CAUTION: BEFORE ROAD TESTING A
VEHICLE, BE SURE THAT ALL
COMPONENTS ARE REASSEMBLED.
DURING THE TEST DRIVE, DO NOT TRY TO
READ THE DRBIIITSCREEN WHILE IN
MOTION. DO NOT HANG THE DRBIIITFROM
THE REAR VIEW MIRROR OR OPERATE IT
YOURSELF. HAVE AN ASSISTANT
AVAILABLE TO OPERATE THE DRBIIIT.
4.3.2 VEHICLE DAMAGE CAUTIONS
Before disconnecting any control module, make
sure the ignition is off. Failure to do so could
damage the module.
11
GENERAL INFORMATION

TEST ACTION APPLICABILITY
7Note: Anything that affects the speed of the crankshaft can cause a misfire
DTC.
The following are other possible causes for mis-fire:
Injector harness connectors, secondary ignition problem, mechanical engine problem,
PCM power grounds, irregular cam and crank signal, plugged injectors, restricted
exhaust, intake restriction, damaged trigger wheel, contaminated fuel, or vacuum
leak.
Weak valve springs, carbon deposits on valves, or accessory drive belt (serpentine
belt).
Check for any TSB's that may relate to a Misfire DTC.
Do any of the above causes exist?All
Ye s®Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
8 At this time the mis-fire does not exist or is an intermittent problem.
Note: An intermittent problem may have been caused by moisture in the
secondary ignition.
With the DRBIIIt, select DTC's AND RELATED FUNCTIONS. Read and record the
FREEZE FRAME DATA. Select OBD II MONITORS. Read and record MIS-FIRE
SIMILAR CONDITIONS WINDOW DATA.
With these screens, attempt to duplicate the condition that has set the Misfire DTC.
While using FREEZE FRAME DATA, pay particular attention to the DTC setting
conditions, such as speed, temp, load, and map vacuum.
Does the mis-fire reoccur?All
Ye s®Go To 9
No®Mis-fire DTC conditions no longer exist. Refer to any TSB's that
may relate to the symptom. Operate the vehicle for 2 misfire good
trip and erase DTC's.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
9 Start the engine and allow the engine to idle.
With the DRBIIIt, read the FREEZE FRAME DATA.
Use the FREEZE FRAME DATA and attempt to determine the cause of the Misfire
DTC.
In the FREEZE FRAME, are the adaptive fuel percentages greater than +/- 15%?All
Ye s®Refer to the Driveablitiy Category and perform the Checking Fuel
Delivery symptom.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 10
10 With the DRBIIIt, read the FREEZE FRAME DATA.
Use the FREEZE FRAME DATA and attempt to determine the cause of the Misfire
DTC.
In the FREEZE FRAME DATA, is the LOAD VALUE over 50% and the operating
temp normal?All
Ye s®Check secondary ignition, compression, and cylinder leakage.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 11
106
DRIVEABILITY - GAS
P0300-MULTIPLE CYLINDER MIS-FIRE ÐContinued

TEST ACTION APPLICABILITY
5WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DRB Freeze Frame information. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
6 Turn the ignition off.
Disconnect the CKP Sensor harness connector.
Turn the ignition on.
Measure the voltage of the 8 Volt Supply circuit in the CKP Sensor harness connector.
Is the voltage between 7.5 and 8.5 volts?All
Ye s®Go To 7
No®Go To 15
7 Turn the ignition off.
Disconnect the CKP Sensor harness connector.
Turn the ignition on.
Measure the voltage of the CKP Sensor Signal circuit in the CKP Sensor harness
connector.
Is the voltage between 4.5 and 5.0 volts?All
Ye s®Go To 8
No®Go To 10
8 Turn the ignition off.
Disconnect the CKP Sensor harness connector.
Disconnect the PCM harness connector.
Measure the resistance of the Sensor Ground circuit between the CKP Sensor
harness connector and the PCM harness connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 9
No®Repair the Sensor Ground circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
9NOTE: Inspect the slots on the flywheel for damage. If a problem is found
repair as necessary.
If there are no possible causes remaining, view repair.All
Repair
Replace the Crankshaft Position Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
11 0
DRIVEABILITY - GAS
P0320-NO CRANK REFERENCE SIGNAL AT PCM ÐContinued

Symptom:
P0500-NO VEHICLE SPEED SIGNAL (3SP AUTO AND MANUAL
TRANSMISSIONS)
When Monitored and Set Condition:
P0500-NO VEHICLE SPEED SIGNAL (3SP AUTO AND MANUAL TRANSMIS-
SIONS)
When Monitored: With the engine running, transmission not in park or neutral, brakes
not applied, and engine rpm greater than 1800.
Set Condition: This code will set if no vehicle speed signal is received from the Vehicle
Speed Sensor for more than 7.2 seconds for 2 consecutive trips.
POSSIBLE CAUSES
INTERMITTENT CONDITION
8 VOLT SUPPLY CIRCUIT OPEN
VEHICLE SPEED SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
VEHICLE SPEED SENSOR SIGNAL CIRCUIT OPEN
PCM VSS SIGNAL
SENSOR GROUND CIRCUIT OPEN
VEHICLE SPEED SENSOR
TEST ACTION APPLICABILITY
1 Raise the drive wheels off the ground.
WARNING: BE SURE TO KEEP HANDS AND FEET CLEAR OF ROTATING
WHEELS.
Start the engine.
With the DRBIIIt, monitor the Vehicle Speed Sensor
Place the transmission in any forward gear.
Allow the wheels to rotate.
Does the DRBIIItdisplay vehicle speed above 0 MPH/KMH?All
Ye s®Go To 2
No®Go To 3
147
DRIVEABILITY - GAS

Symptom:
P0740-TORQ CONV CLU, NO RPM DROP AT LOCKUP (3SP AUTO
TRANS)
When Monitored and Set Condition:
P0740-TORQ CONV CLU, NO RPM DROP AT LOCKUP (3SP AUTO TRANS)
When Monitored: Run in third with converter unlocked for 10 seconds, apply throttle
until it locks then run for 5 seconds, vehicle speed less than 60 MPH. No DTCs set for: TCC
solenoids, any cam/crank conditions, VSS, TPS signal, TPS voltage too high or too low.
Set Condition: Torque converter malfunctions are detected when it does not lock or
unlock properly. Two consecutive trips that fail will store the code. Mountainous terrain
may cause this trouble code.
POSSIBLE CAUSES
INTERMITTENT CONDITION
DTCS PRESENT
TRANSMISSION FLUID
TIRE AND WHEEL SIZE
FUSED IGNITION OUTPUT CIRCUIT
TCC SOLENOID
TCC ASSEMBLY OR TCC SOLENOID STUCK
TCC SOLENOID OPERATION
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip Counter displayed and equal to zero?All
Ye s®Go To 2
No®Go To 9
165
DRIVEABILITY - GAS

TEST ACTION APPLICABILITY
2 Turn the ignition on.
With the DRBIIIt, read DTCs.
Are any of the following DTCs set in the PCM memory?
P0122 - Throttle Position Sensor Voltage Low
P0123 - Throttle Position Sensor High
P0320 - No Crank Reference Signal At PCM
P0743 - Torque Converter Clutch Solenoid/Trans Relay Circuits
P0300, P0301, P0302, P0303 or P0304 Misfire DTC(s)
Did any of the above DTCs set along with P0740All
Ye s®Refer to the Driveability Category and perform the appropriate
symptom before proceeding.
Perform 31TH TRANSMISSION VERIFICATION TEST - VER
1..
No®Go To 3
3 Check the transmission fluid level and condition.
Is the fluid level OK and free of contamination?All
Ye s®Go To 4
No®Repair the fliuld level and/or condition as necessary.
Perform 31TH TRANSMISSION VERIFICATION TEST - VER
1..
4 Inspect the front wheels and tires. Ensure the wheels and tires are the manufactures
recommended size.
Ensure both left and right wheels and tires are the same size.
Were any problems found?All
Ye s®Repair or replace as necessary.
Perform 31TH TRANSMISSION VERIFICATION TEST - VER
1..
No®Go To 5
5 Turn the ignition off.
Disconnect the TCC Solenoid harness connector.
Turn the ignition on.
Measure the voltage of the Fused Ignition Switch Output circuit in the TCC Solenoid
harness connector.
Is the voltage above 10.0 volts?All
Ye s®Go To 6
No®Repair the Fused Ignition Switch Output circuit for an open.
Perform 31TH TRANSMISSION VERIFICATION TEST - VER
1..
6 Turn the ignition off.
Disconnect the TCC Solenoid harness connector.
Measure the resistance across the TCC Solenoid.
Is the resistance between 30.0 and 50.0 ohms?All
Ye s®Go To 7
No®Replace the TCC Solenoid.
Perform 31TH TRANSMISSION VERIFICATION TEST - VER
1..
166
DRIVEABILITY - GAS
P0740-TORQ CONV CLU, NO RPM DROP AT LOCKUP (3SP AUTO TRANS)
Ð
Continued