CHECKING FOR OXYGEN
SENSOR SWITCHING
CHECKING O2S HEATER
CHECKING IDLE AIR CON-
TROL MOTOR OPERATION
CHECKING ENGINE ME-
CHANICAL SYSTEMS
CHECKING EVAP EMISSION
SYSTEM
CHECKING EGR SYSTEM
CHECKING IAT SENSOR
CHECKING PNP SWITCH
3.4 USING THE DRBIIIT
Refer to the DRBIIItuser 's guide for instructions
and assistance with reading trouble codes, erasing
trouble codes, and other DRBIIItfunctions.
3.5 DRB ERROR 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.
This is a sample of such an error message display:
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 DRB IIITDOES 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 vehicle or other devices, and the
vehicle battery is fully charged, an inoperative
DRBIIItmay be the result of a faulty cable or
vehicle wiring. For a blank screen, refer to the
appropriate body diagnostics manual.
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 impor-
tant 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
11
GENERAL INFORMATION
ProCarManuals.com
Symptom:
P-0320 NO CRANK REFERENCE SIGNAL AT PCM
When Monitored and Set Condition:
P-0320 NO CRANK REFERENCE SIGNAL AT PCM
When Monitored: During cranking, with battery voltage between 4.0 volts and 11.6 volts
and manifold vacuum present.
Set Condition: No signal from the crank position sensor is present during engine
cranking or the cam position signal is present with no crank signal.
POSSIBLE CAUSES
CKP SENSOR DEFECTIVE
CRANK POSITION SENSOR GROUND CIRCUIT OPEN
CRANKSHAFT NOTCHES DAMAGED
FLYWHEEL DAMAGED
8-VOLT SUPPLY CIRCUIT OPEN
8-VOLT SUPPLY CIRCUIT SHORT TO GROUND
CKP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
CMP/CKP SENSOR WIRING HARNESS INTERMITTENT DEFECT
CMP/CKP SENSOR WIRING HARNESS OBSERVABLE DEFECT
CRANK POSITION SENSOR SIGNAL CIRCUIT OPEN
PCM DEFECTIVE
PCM DEFECTIVE (NO CRANK REF SIG)
TEST ACTION APPLICABILITY
1 Cycle the ignition off, then on.
Attempt to start engine.
With the DRB in Input/Output display, read the current CMP and CKP states.
Did the CMP or CKP states change to present while cranking engine?All
Ye s®Go To 2
No®Go To 6
2 Cycle the ignition off, then on.
Attempt to start engine.
With the DRB in Input/Output display, read the current CMP and CKP states.
Did only the CMP state change while cranking engine?All
Ye s®Go To 6
No®Go To 3
108
DRIVEABILITY
ProCarManuals.com
TEST ACTION APPLICABILITY
8 Ignition Off
Disconnect the Crank Position (CKP) Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Connect one end of a jumper wire to the Crank Position Signal Circuit.
Turn ignition on.
With the DRB, monitor the current CKP state.
Tap the other end of jumper to Sensor ground several times.
Does the CKP state change to present?All
Ye s®Go To 9
No®Go To 10
9 Ignition Off
Remove the Crankshaft Position (CKP) Sensor.
Inspect the Flywheel for damage. (3.0L, 3.3L and 3.8L)
Inspect the Crankshaft Notches for debris or damage.
Is the Flywheel damaged?All
Ye s®Repair as necessary.
Perform Powertrain Verification Test VER-2A.
No®Replace the Crankshaft Position Sensor.
Perform Powertrain Verification Test VER-2A.
10 Ignition Off
Disconnect the Crank Position (CKP) Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the Powertrain Control Module Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure resistance of the CKP Signal Circuit to a good ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Crank Position Sensor Signal Circuit for a short to
ground. Note: Check TCM for short.
Perform Powertrain Verification Test VER-2A.
No®Go To 11
11 Ignition Off
Disconnect the Crank Position (CKP) Sensor Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the Powertrain Control Module Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the CKP Sensor Signal Circuit from
the CKP Sensor Connector to the PCM Connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 12
No®Repair the open Crank Position Sensor Signal Circuit.
Perform Powertrain Verification Test VER-2A.
11 0
DRIVEABILITY
P-0320 NO CRANK REFERENCE SIGNAL AT PCM ÐContinued
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