TEST ACTION APPLICABILITY
4NOTE: If DTC P1611 or P2306 is present with this DTC, diagnose DTCs P1611
and P2306 before diagnosing this DTC.
Turn the ignition off.
Disconnect the EGR Valve 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 the EGR Valve Control circuit.
Is the voltage below 0.5 volt?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the EGR Valve Control circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
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 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.
226
DRIVEABILITY - DIESEL
P2527-EGR VALVE SIGNAL CIRCUIT SHORTED TO VOLTAGE ÐContinued
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: This DTC indicates an internal ECM problem except in the case of
DTC P0606 where it may indicate a fuel injector problem. Using the Service
Information, check the fuel injectors for leakage before replacing the ECM.
Turn the ignition on.
With the DRBIIIt, erase ECM DTCs.
Perform several engine run cycles, turning the ignition off for at least 20 seconds
between each engine run cycle.
With the DRBIIIt, read the ECM DTCs.
Did this DTC set again?All
Ye s!Replace the Fuel Injector identified in the DTC in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 2
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.
228
DRIVEABILITY - DIESEL
P2531-FUEL INJECTOR 1 READ TOO LARGE ÐContinued
Symptom:
P2606-CMP/CKP SYNCHRONIZATION ERROR
POSSIBLE CAUSES
CAMSHAFT POSITION SENSOR SIGNAL PROBLEM
CRANKSHAFT POSITION SENSOR SIGNAL PROBLEM
DAMAGED CKP SENSOR
DAMAGED CMP SENSOR OR CAMSHAFT
ENGINE CONTROL MODULE
GEAR ALIGNMENT PROBLEM
INTERMITTENT CONDITION
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.
Attempt to start the engine.
With the DRBIIIt, read the ECM DTCs.
Does the DRB III display this DTC?All
Ye s!Go To 3
No!Go To 2
2 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 this DTC?All
Ye s!Go To 3
No!Go To 8
3 Refer to the Service Information to ensure the Engine Drive Gears/Sprocket are
installed correctly and the camshaft and crankshaft gears are timed correctly.
Turn the ignition off.
Remove the CMP Sensor.
Inspect the CMP Sensor for conditions such as loose mounting screws, damage or
debris, also check the camshaft for cracked teeth.
Is there any evidence of these conditions?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
229
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
4 Turn the ignition off.
Remove the CKP Sensor.
Inspect the CKP Sensor for conditions such as loose mounting screws, damage or
debris.
Is there any evidence of these conditions?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 5
5 Turn the ignition off.
Using the DRB lab scope, backprobe the CMP Sensor Signal circuit at the CMP
Sensor harness connector.
Start the engine, if the engine will not start, crank the engine for several seconds
while monitoring the DRB.
NOTE: Refer to Charts and Graphs to view a correct CMP Sensor signal.
Does the DRB display a steady clean CMP Signal pattern?All
Ye s!Go To 6
No!Perform Test for DTC P2043-Camshaft Position Sensor Circuit
Static Plausibility.
Perform ROAD TEST VERIFICATION - VER-2.
6 Turn the ignition off.
Using the DRB lab scope, backprobe both of the CKP Sensor Signal circuits at the
CKP Sensor 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 each circuit?All
Ye s!Go To 7
No!Perform Test for DTC P2045-Crankshaft Position Sensor Circuit
Dynamic Plausibility.
Perform ROAD TEST VERIFICATION - VER-2.
7 Refer to the Service Information and check alignment of the camshaft sprocket,
crankshaft sprocket and injection pump sprocket.
Are all of the sprockets aligned correctly?All
Ye s!Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair or adjust as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
230
DRIVEABILITY - DIESEL
P2606-CMP/CKP SYNCHRONIZATION ERROR ÐContinued
TEST ACTION APPLICABILITY
8WARNING: 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.
231
DRIVEABILITY - DIESEL
P2606-CMP/CKP SYNCHRONIZATION ERROR ÐContinued
Symptom:
*ENGINE CRANKS BUT WILL NOT START
POSSIBLE CAUSES
CAMSHAFT POSITION SENSOR SIGNAL PROBLEM
CRANKSHAFT POSITION SENSOR SIGNAL PROBLEM
ECM CODES PRESENT
ECT SENSOR
ENGINE CONTROL MODULE
ENGINE DRIVE GEAR/SPROCKET
FUEL SUPPLY CONTAMINATION
FUEL SYSTEM PRESSURE MECHANICAL
FUEL SYSTEM RESTRICTION
GLOW PLUGS
SKIM CODES PRESENT
TEST ACTION APPLICABILITY
1NOTE: The ECM must have proper power and ground connections for the
following tests to be valid. Refer to Checking the ECM Power and Grounds
in the symptom list.
NOTE: A no-start condition may occur if the Fuel Temperature Sensor is
shorted or if the Fuel Temperature Sensor Signal circuit is shorted to
ground or shorted to Sensor Ground.
Turn the ignition on.
With the DRBIIIt, read the ECM DTCs.
Does the DRBIIItdisplay any ECM DTCs?All
Ye s!Refer to symptom list for problems related to ECM DTC.
Perform NO START VERIFICATION - VER-1.
No!Go To 2
2 Turn the ignition on.
With the DRBIIIt, read the SKREEM DTCs.
Does the DRBIIItdisplay any SKREEM DTCs?All
Ye s!Refer to symptom list for problems related to SKIM DTC.
Perform NO START VERIFICATION - VER-1.
No!Go To 3
3 Using a temperature probe, check the vehicle temperature near the ECT Sensor.
Turn the ignition on.
With the DRBIIItin Sensors, read the ECT Sensor temperature.
Compare the temperature probe reading with the DRBIIItreading.
Are the two readings within 10ÉC of each other?All
Ye s!Go To 4
No!Repair as necessary.
Perform NO START VERIFICATION - VER-1.
239
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
4NOTE: Prior to performing this test, be sure to check the Glow Plug Relay
operation. Refer to CHECKING GLOW PLUG OPERATION for the related
symptom(s).
Refer to the Service Information and check the Glow Plugs for proper operation.
Are the Glow Plugs operating properly?All
Ye s!Go To 5
No!Repair as necessary.
Perform NO START VERIFICATION - VER-1.
5 Inspect the fuel system lines for restrictions, leaks or other problems.
NOTE: Refer to the Service Information to ensure that the fuel system is
properly primed. An unprimed system or excessive air in the supply system
will cause a no-start condition.
Is there any evidence of problems?All
Ye s!Repair as necessary.
Perform NO START VERIFICATION - VER-1.
No!Go To 6
6 Refer to the Service Information and perform the fuel pressure test.
Is the fuel pressure within specification?All
Ye s!Go To 7
No!Repair as necessary.
Perform NO START VERIFICATION - VER-1.
7 Inspect the fuel supply for contamination.
Is the fuel contaminated?All
Ye s!Refer to the Service Information to remove and replace fuel
throughout the fuel system.
Perform NO START VERIFICATION - VER-1.
No!Go To 8
8 Turn the ignition off.
Using the DRBIIItlab scope, backprobe the CMP Sensor Signal circuit at the ECM
harness connector.
Start the engine, if the engine will not start, crank the engine for several seconds
while monitoring the DRBIIIt.
NOTE: Refer to Charts and Graphs to view a correct CMP Sensor signal.
Does the DRBIIItdisplay a steady clean CMP Signal pattern?All
Ye s!Go To 9
No!Perform Test for DTC P2043-Camshaft Position Sensor Circuit
Static Plausibility.
Perform NO START VERIFICATION - VER-1.
240
DRIVEABILITY - DIESEL
*ENGINE CRANKS BUT WILL NOT START ÐContinued
Symptom:
*ENGINE WILL NOT CRANK
POSSIBLE CAUSES
BATTERY CABLE HIGH RESISTANCE
BATTERY CABLES
CHECKING ECM POWER AND GROUNDS
CHECKING FOR TCM CODES
ECM
ECM CODES PRESENT
IGNITION SWITCH OUTPUT (START) CIRCUIT OPEN
MECHANICAL PROBLEM
SKREEM CODES PRESENT
STARTER MOTOR
STARTER MOTOR RELAY
STARTER MOTOR RELAY CIRCUIT(S) OPEN
STARTER MOTOR RELAY CIRCUIT(S) SHORTED TO GROUND
STARTER RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE
STARTER RELAY OUTPUT CIRCUIT OPEN
TEST ACTION APPLICABILITY
1 Turn the ignition off.
NOTE: The battery must be fully charged before diagnosing a no crank
condition.
Inspect the battery cables for corrosion, looseness or other problems.
Is there evidence of problems?All
Ye s!Repair as necessary.
Perform NO START VERIFICATION - VER-1.
No!Go To 2
2 Turn the ignition off.
Remove the Starter Motor Relay from the Fuse/Relay Block.
Connect a test light between cavities 85 and 86 of the Starter Motor Relay connector
in the Fuse/Relay Block connector.
While observing the test light, attempt to start the engine.
Did the test light illuminate when turning the ignition switch to the Crank position?All
Ye s!Go To 3
No!Go To 8
242
DRIVEABILITY - DIESEL