
TEST ACTION APPLICABILITY
8 Refer to the appropriate Service Information and refer to Diagnosis and Testing Fuel
Delivery System table.
NOTE: The following is a list of problems that can cause fuel pressure to
deviate from specification: restricted fuel filter or fuel lines, failed fuel
pressure solenoid, failed fuel lift pump, failed fuel sending unit, contami-
nated fuel, faulty injector.
Were there any problems with the Fuel Delivery System?All
Ye s!Repair as necessary in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 9
9 Refer to each of the following symptoms in the Driveability category.
CHECKING THE FUEL PRESSURE SOLENOID CIRCUITS
CHECKING THE FUEL QUANTITY SOLENOID CIRCUITS
CHECKING THE FUEL PRESSURE SENSOR CIRCUITS
Were any problems found?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 10
10NOTE: An injector that sticks open can cause this DTC. A sticking injector
will cause the engine to misfire and emit excessive black smoke from the
exhaust system.
Refer to the Service Information and perform the Fuel Injector Leak Quantity Test.
Were any problems found?All
Ye s!Using the Service Information, remove and inspect the Fuel
Injectors for signs of damage or debris that may cause the injector
to stick. Sticking injectors may cause the combustion chamber to
become black and oil soaked. Replace Injector(s) as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 11
11 With the DRBIIIt, select System Test, Smooth Eng Run Check, then Correction
Quantity Check.
Perform this test at Idle, 2000 rpm and 3000 rpm.
NOTE: Readings per cylinder should be below 0.00450 mm
3/stroke for each
cylinder at each engine speed.
Did any of the cylinders exceed 0.00450 mm
3/stroke during this test?All
Ye s!Replace Fuel Injector of the cylinder(s) that had readings above
0.00450 mm
3/stroke.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 12
12 With the DRBIIIt, select System Test, Smooth Eng Run Check, then Cylinder Speed
Check.
NOTE: Readings for all cylinders should be close to each other. Look for one
or two cylinders to differ high or low from the other cylinders.
Did any of the cylinders differ significantly from the majority of the other cylinders?All
Ye s!Replace Fuel Injector of the cylinder(s) that had readings signif-
icantly above or below the other fuel injectors.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 13
121
DRIVEABILITY - DIESEL
P2015-FUEL RAIL PRESSURE MALFUNCTION MAXIMUM FUEL FLOW
EXCEEDED Ð
Continued

TEST ACTION APPLICABILITY
17 Refer to the appropriate Service Information and refer to Diagnosis and Testing Fuel
Delivery System table.
NOTE: The following is a list of problems that can cause fuel pressure to
deviate from specification: restricted fuel filter or fuel lines, failed fuel
pressure solenoid, air in fuel system, failed fuel sending unit, contaminated
fuel, faulty injector.
Were there any problems with the Fuel Delivery System?All
Ye s!Repair as necessary in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 18
18 Refer to each of the following symptoms in the Driveability category.
CHECKING THE FUEL PRESSURE SOLENOID CIRCUITS
CHECKING THE FUEL QUANTITY SOLENOID CIRCUITS
CHECKING THE FUEL PRESSURE SENSOR CIRCUITS
Were any problems found?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 19
19NOTE: An injector that sticks open can cause this DTC. A sticking injector
will cause the engine to misfire and emit excessive black smoke from the
exhaust system.
Refer to the Service Information and perform the Fuel Injector Leak Quantity during
engine cranking test.
Were any problems found?All
Ye s!Using the Service Information, remove and inspect the Fuel
Injectors for signs of damage or debris that may cause the injector
to stick. Sticking injectors may cause the combustion chamber to
become black and oil soaked. Replace Injector(s) as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 20
20 Turn the ignition off.
Replace the Fuel Pressure Solenoid in accordance with the Service Information.
Turn the ignition on.
With the DRBIIIt, erase the ECM DTCs.
Attempt to start and test drive the vehicle.
With the DRBIIIt, read the ECM DTCs.
Did this DTC set again?All
Ye s!Go To 21
No!Test Complete.
123
DRIVEABILITY - DIESEL
P2015-FUEL RAIL PRESSURE MALFUNCTION MAXIMUM FUEL FLOW
EXCEEDED Ð
Continued

Symptom:
P2025-INTAKE PRESSURE SENSOR PLAUSIBILITY
When Monitored and Set Condition:
P2025-INTAKE PRESSURE SENSOR PLAUSIBILITY
When Monitored: With the ignition on.
Set Condition: The Intake Pressure Sensor signal does not agree with the Atmospheric
Pressure Sensor signal in the ECM.
POSSIBLE CAUSES
AIR FILTER
AIR RESTRICTION
INTERMITTENT CONDITION
HIGH RESISTANCE IN THE INTAKE PRESSURE SENSOR SIGNAL CIRCUIT
HIGH RESISTANCE IN THE INTAKE PRESSURE SENSOR GROUND CIRCUIT
HIGH RESISTANCE IN THE INTAKE PRESSURE SENSOR 5-VOLT SUPPLY CIRCUIT
ENGINE CONTROL MODULE
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: 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.
Turn the ignition off, wait 30 seconds.
Test drive the vehicle.
With the DRB, read ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 7
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
125
DRIVEABILITY - DIESEL

Symptom:
P2062-ENGINE OIL SENSOR MONITORING ERROR
POSSIBLE CAUSES
ENGINE OIL SENSOR
VERIFY THE CURRENT DTC
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Check the engine oil level. Add or remove as necessary to obtain proper engine oil
level.
Start the engine and allow it to reach operating temperature.
Test drive the vehicle.
With the DRBIIIt, read the ECM DTCs.
Did this DTC set again?All
Ye s!Replace the Engine Oil Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test complete.
Perform ROAD TEST VERIFICATION - VER-2.
149
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:
P2332-SENSOR SUPPLY 3 VOLTAGE IS TOO LOW
POSSIBLE CAUSES
ENGINE OIL SENSOR
INTAKE AIR PRESSURE SENSOR
VISUAL WIRING AND CONNECTOR INSPECTION
INTERMITTENT CONDITION
SENSOR SUPPLY VOLTAGE 3 SHORTED TO GROUND
ENGINE CONTROL MODULE
ENGINE OIL SENSOR SIGNAL CIRCUIT SHORTED TO SENSOR GROUND CIRCUIT
INTAKE AIR PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO SENSOR GROUND CIRCUIT
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.
Turn the ignition off for 10 seconds.
Turn the ignition on.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 8
2 Turn the ignition off.
Visually inspect the wiring and connectors associated with the Intake Air Pressure
Sensor and Engine Oil Sensors for problems that may result in a short circuit.
Were any problems found?All
Ye s!Repair or replace wiring/connectors as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
3 Turn the ignition off.
Disconnect the Intake Air Pressure Sensor and Engine Oil Sensor harness connec-
tors.
Disconnect the ECM harness connectors.
Measure the resistance between ground and all of the EOS and Intake Air Pressure
Sensor harness connector cavities.
Is the voltage below 1000 ohms for any of the measurements?All
Ye s!Repair the circuit(s) that measured below 1000 ohms for a short to
ground.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
203
DRIVEABILITY - DIESEL

Symptom:
P2332-SENSOR SUPPLY 3 VOLTAGE IS TOO HIGH
POSSIBLE CAUSES
EO SENSOR
INTAKE AIR PRESSURE SENSOR
VISUAL WIRING AND CONNECTOR INSPECTION
INTERMITTENT CONDITION
SENSOR SUPPLY VOLTAGE 3 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, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Start the engine.
Monitor the DRB for ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 6
2 Turn the ignition off.
Visually inspect the wiring and connectors associated with the Intake Air Pressure
Sensor and Engine Oil Sensors for problems that may result in a short circuit.
Were any problems found?All
Ye s!Repair or replace wiring/connectors as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
206
DRIVEABILITY - DIESEL

Symptom List:
P2359-BOOST PRESSURE TOO HIGH
P2359-BOOST PRESSURE TOO LOW
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P2359-BOOST PRESSURE TOO
HIGH.
POSSIBLE CAUSES
AIR FILTER
AIR RESTRICTION
CHECKING FOR AIR LEAKS
INTERMITTENT CONDITION
BOOST PRESSURE SERVO MOTOR
TURBOCHARGER
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.
NOTE: Ensure all turbocharger inlet and outlet tubes are connected prop-
erly, without damage and restriction before continuing with this test. Also
ensure the Boost Pressure Servo Motor and Servo Motor rod are attached
and functioning properly.
Turn the ignition on.
With the DRBIIIt, erase ECM DTCs.
Test drive the vehicle.
Monitor the DRBIIItfor ECM DTCs.
Did this DTC set again?All
Ye s!Go To 2
No!Go To 6
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
216
DRIVEABILITY - DIESEL