
TEST ACTION APPLICABILITY
8 Turn the ignition off.
Remove the CMP Sensor.
Inspect the CMP Sensor for conditions such as loose mounting screws, damage, or
cracks.
Inspect the camshaft for conditions such as damage, debris or cracked teeth.
Is there any evidence of these conditions?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 9
9 Turn the ignition off.
With the DRBIIItlab scope lead, backprobe the CMP Signal circuit.
Set the DRBIIItlab scope settings as follows: Time = 0.2s/Div, 20 volts scale, Offset
= 0.00 volts, Probe = X10, Coupling = DC.
While observing the DRBIIItdisplay, crank the engine.
NOTE: The DRBIIItshould display a digital signal (square wave) similar to
that shown in Charts and Graphs.
Does the DRBIIItdisplay an uninterrupted digital signal (square wave)?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Replace the Camshaft Position Sensor in accordance with the
Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
10 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the CMP Sensor harness connector.
Measure the resistance of the 5-Volt Supply circuit between the ECM harness
connector and the CMP Sensor harness connector.
Is the resistance below 10.0 ohms?All
Ye s!Go To 11
No!Repair the 5-Volt Supply circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
11 Turn the ignition off.
Disconnect the CMP Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the CMP Sensor 5-Volt Supply circuit.
Is the resistance above 1000 ohms?All
Ye s!Go To 12
No!Repair the CMP Sensor 5-Volt Supply circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
143
DRIVEABILITY - DIESEL
P2043-CAMSHAFT POSITION SENSOR CIRCUIT OPEN CIRCUIT Ð
Continued

Symptom List:
P2045-CRANKSHAFT POSITION SENSOR CIRCUIT LOST SIGNAL
P2045-CRANKSHAFT POSITION SENSOR CIRCUIT SIGNAL PLAU-
SIBILITY
P2322-CRANKSHAFT POSITION SENSOR PLAUSIBILITY
P2343-CKP PLAUSIBILITY
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2045-CRANKSHAFT POSITION
SENSOR CIRCUIT LOST SIGNAL.
POSSIBLE CAUSES
CKP MOUNTING AND FLYWHEEL
CRANKSHAFT POSITION SENSOR
ENGINE CONTROL MODULE
OPEN SHIELD CIRCUIT
INTERMITTENT CONDITION
CRANKSHAFT POSITION SENSOR SIGNAL CIRCUIT(S) SHORTED TO GROUND
CKP SENSOR CIRCUITS SHORTED TOGETHER
CKP SENSOR SIGNAL CIRCUITS OPEN
CKP SENSOR SIGNAL CIRCUIT(S) SHORTED TO VOLTAGE
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Attempt to start the engine.
Did the engine start?All
Ye s!Go To 2
No!Go To 3
146
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
6 Turn the ignition off.
Disconnect the CKP Sensor harness connector.
Disconnect the ECM harness connectors.
Remove the Engine Control Relay.
Connect a jumper wire between cavity 30 and cavity 87 of the Engine Control Relay
connector.
Turn the ignition on.
Measure the voltage of both CKP Sensor Signal circuits.
Is the voltage below 1.0 volt for both measurements?All
Ye s!Go To 7
No!Repair the CKP Sensor Signal circuit(s) for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
7 Turn the ignition off.
Using the DRB lab scope, backprobe both of the CKP Sensor Signal circuits at the
ECM harness connector.
NOTE: Refer to Charts and Graphs to view a correct CKP Sensor signal.
Start the engine, if the engine will not start, crank the engine for several seconds
while monitoring the DRB.
Does the DRB display a steady clean CKP Signal pattern for both circuits?All
Ye s!Go To 8
No!Replace the Crankshaft Position Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
8 Turn the ignition off.
Inspect the CKP Sensor Shield circuit.
Were any problems found?All
Ye s!Repair the Shield circuit as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 9
9 Turn the ignition off.
Inspect the CKP Sensor for signs of damage or improper/loose attachment to the
engine.
Inspect the flywheel for excessive dirt contamination or tooth damage which can
cause improper CKP Sensor signal output.
Where any of these problems found?All
Ye s!Repair or replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
148
DRIVEABILITY - DIESEL
P2045-CRANKSHAFT POSITION SENSOR CIRCUIT LOST SIGNAL Ð
Continued

Symptom List:
P2066-MASS AIR FLOW SENSOR PLAUSIBILITY
P2355-EGR FLOW RATE IS TOO HIGH
P2355-EGR FLOW RATE IS TOO LOW
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2066-MASS AIR FLOW SENSOR
PLAUSIBILITY.
When Monitored and Set Condition:
P2066-MASS AIR FLOW SENSOR PLAUSIBILITY
When Monitored: With the engine running.
Set Condition: The ECM detects a rationality problem with the MAF Sensor or excessive
EGR flow.
POSSIBLE CAUSES
AIR FILTER
AIR RESTRICTION
CHECKING FOR AIR LEAKS
EGR ACTUATION - 1200 RPM
EGR VALVE
MAF SENSOR
MAF SENSOR READING - 3OOO RPM
INTERMITTENT CONDITION
EGR RESTRICTION
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Test drive the vehicle and monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 10
150
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
1NOTE: If DTC P1611, P2306 or P2332 is present with this DTC, diagnose
DTCs P1611, P2306 or P2332 before diagnosing this DTC.
NOTE: Inspect all air intake and turbocharger related tubes for damage,
restriction or poor connection. Any of these conditions can cause a this DTC
to set.
NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRBIIIt, erase the ECM DTCs.
Test drive the vehicle.
With the DRBIIIt, read the ECM DTCs.
Does the DRB III display a Mass Air Flow Sensor DTC?All
Ye s!Go To 2
No!Go To 5
2 Turn the ignition off.
Remove and inspect the Air Filter for soiling or excessive dirt and debris which may
cause air flow restriction.
Were any of these problems found?All
Ye s!Replace the Air Filter element.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
3NOTE: Inspect all air intake and turbocharger related tubes for damage,
restriction or poor connection. Any of these conditions can cause a this DTC
to set.
NOTE: Inspect the exhaust system and related tubes for damage, restriction
or poor connection. Any of these conditions can cause a this DTC to set.
Turn the ignition off.
Inspect the intake system, exhaust system and related tubes and connections.
Were any problems found?All
Ye s!Repair or replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
4 Turn the ignition off.
Remove the Intake Air Temperature Sensor.
Connect smoke machine 84-04 to the Intake Air Temperature Sensor port in the
intake duct and begin injecting smoke into the intake system.
Observe all intake system components for evidence of smoke leakage.
Is there evidence of smoke leakage?All
Ye s!Repair or replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Replace the MAF Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
154
DRIVEABILITY - DIESEL
P2066-MASS AIR FLOW SENSOR PLAUSIBILITY AIR MASS TOO HIGH Ð
Continued

Symptom List:
P2100-FUEL PUMP RELAY CIRCUIT OPEN CIRCUIT
P2100-FUEL PUMP RELAY CIRCUIT SHORTED TO GROUND
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2100-FUEL PUMP RELAY
CIRCUIT OPEN CIRCUIT.
POSSIBLE CAUSES
INTERMITTENT CONDITION
ENGINE CONTROL RELAY OUTPUT CIRCUIT OPEN
FUEL LIFT PUMP RELAY
FUEL LIFT PUMP RELAY CONTROL CIRCUIT SHORTED TO GROUND
FUEL LIFT PUMP RELAY CONTROL CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRBIIIt, erase the ECM DTCs.
Crank and attempt to start the engine several times.
With the DRBIIIt, read the active ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 6
2 Turn the ignition off.
Remove the Fuel Lift Pump Relay.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Engine Control Relay
Output circuit.
Did the test light illuminate brightly?All
Ye s!Go To 3
No!Refer to Checking the ECM Power and Grounds for the related
symptom(s).
Perform ROAD TEST VERIFICATION - VER-2.
157
DRIVEABILITY - DIESEL

Symptom List:
P2100-FUEL PUMP RELAY CIRCUIT SHORTED TO VOLTAGE
P2100-FUEL PUMP RELAY EXCESSIVE CURRENT
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2100-FUEL PUMP RELAY
CIRCUIT SHORTED TO VOLTAGE.
POSSIBLE CAUSES
INTERMITTENT CONDITION
FUEL LIFT PUMP RELAY
FUEL LIFT PUMP RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, actuate the Fuel Lift Pump Relay.
Does the Fuel Lift Pump Relay cycle on and off?All
Ye s!Go To 2
No!Go To 3
2WARNING: 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 DTC When Monitored and Set Conditions. 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 ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
159
DRIVEABILITY - DIESEL

Symptom List:
P2104-STARTER RELAY CIRCUIT SHORT CIRCUIT
P2152-STARTER RELAY CIRCUIT SHORT TO GROUND
P2153-STARTER RELAY CIRCUIT OPEN OR SHORTED TO VOLT-
AGE
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2104-STARTER RELAY CIR-
CUIT SHORT CIRCUIT.
When Monitored and Set Condition:
P2104-STARTER RELAY CIRCUIT SHORT CIRCUIT
When Monitored: During engine crank attempt.
Set Condition: The ECM detects too much current on the Starter Motor Relay Control
circuit.
POSSIBLE CAUSES
CHECKING THE ENGINE CONTROL RELAY SYSTEM
INTERMITTENT CONDITION
SUBSTITUTE STARTER RELAY
STARTER RELAY CONTROL CIRCUIT SHORTED TO GROUND
STARTER RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE
ENGINE CONTROL MODULE
STARTER RELAY CONTROL CIRCUIT OPEN
TEST ACTION APPLICABILITY
1NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Attempt to start the engine several times, pausing for at least 10 seconds between
each cycle.
Turn the ignition on.
With the DRB, read ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 8
161
DRIVEABILITY - DIESEL