Page 881 of 5267

*CHECKING THE ACCELERATOR PEDAL SENSOR CALIBRATION
Possible Causes
MIS-WIRED APPS
VOLTAGE NOT CHANGING DURING SWEEP
THROTTLE PEDAL NOT MOVING FREELY
APPS
Diagnostic Test
1.MIS-WIRED APPS
Turn the ignition off.
Remove the APPS cover.
Inspect both APPS connector and ECM for proper wiring.
Are both connectors wired correctly?
Ye s>>
Go To 2
No>>
Repair mis-wired APPS connector at APPS or ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.THROTTLE PEDAL NOT MOVING FREELY
Ignition on, engine not running.
Look for proper Throttle operation.
Does the Throttle Pedal move freely between the upper and lower stops?
Ye s>>
Replace the APPS.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 882 of 5267

*CHECKING THE ECM POWER AND GROUNDS
For a complete wiring diagramRefer to Section 8W.
Possible Causes
ECM GROUND CIRCUIT(S) OPEN
FUSED B+ CIRCUIT OPEN
FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
Diagnostic Test
1.ECM GROUND CIRCUIT(S) OPEN
Turn the ignition off.
Disconnect the ECM harness connectors.
Using a 12-volt test light connected to 12-volts, check each of the ECM ground circuits in ECM harness connector.
Did the test light illuminate for each cavity?
Ye s>>
Go To 2
No>>
Repair the ECM Ground circuit(s) for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Fused Ignition Switch Output circuit in ECM harness con-
nector.
Is the test light on?
Ye s>>
Go To 3
No>>
Repair the Fused Ignition Switch Output circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
3.FUSED B+ CIRCUIT OPEN
Turn the ignition off.
Disconnect the ECM harness connectors.
Using a 12-volt test light connected to ground, check each Fused B+ circuitin the ECM harness connector.
Does the test light illuminatebrightly for each circuit?
Ye s>>
Te s t C o m p l e t e .
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Repair the Fused B+ Output circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 883 of 5267

* PRESSURE LIMITING VALVE TEST
Possible Causes
PRESSURE LIMITING VALVE DIAGNOSTICS
Diagnostic Test
1.PRESSURE LIMITING VALVE
Using the scan tool, measure the rail pressure and determine if the rail pressure is excessive (above 185,000 kpa/
26,831 psi), if it is, troubleshoot for excessive rail pressure first.
Remove the banjo bolt from the pressure-limiting valve on the fuel rail.
Install fuel system test fitting (9013) into the pressure-limiting valve.
Attach one end of a fuel hose to the fuel fitting and put the other end of the fuel hose into a container.
Perform the tests listed below to determine if the pressure-limiting valve is leaking.
a. Operate the engine at idle and watch for fuel flow into the fuel container.
b. Operate the engine at idle and actuate the high pressure safety valve test with the scan tool. Watch for fuel flow
into the fuel container.
If fuel flows into the fuel container, replace the pressure-limiting valve. If fuel does not leak from the pressure-limiting
valve, the test is complete.
NOTE: do not drive the vehicle with any portion of this test kit installed.
view repair
Ye s>>
Repair complete
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 884 of 5267

*ENGINE SURGES
Possible Causes
DTC/PRODUCT IMPROVEMENT
FUEL SUPPLY SYSTEM
INJECTION SYSTEM
FUEL RETURN
INTAKE SYSTEM
OTHER VEHICLE SYSTEMS
BASE ENGINE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.DTC/PRODUCT IMPROVEMENT
Check for any TSB’s related to customer’s complaint or DTC’s present.
Follow appropriate guidelines in DTC troubleshooting tree or instructions in TSB.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.FUEL SUPPLY SYSTEM
Verify proper fuel quality, grade and level in vehicle.
Use scan tool to monitor fuel rail pressure. If pressure does not fluctuatemore then +/- 500 psi of setpoint than the
fuel system is not the cause of the complaint. Proceed to step3. If condition exist continue.
Verify proper low pressure supply to the Injection Pump by performing the “*IN-TANK FUEL LIFT PUMP FLOW
TEST - DIESEL” Procedure.
Use the “*HIGH PRESSURE FUEL PUMP PERFORMANCE TEST - DIESEL” to check for failed fuel pump.
Perform “*CHECKING PRESSURE LIMITING VALVE ON THE FUEL - DIESEL”.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 3
Page 885 of 5267

3.INJECTION SYSTEM
Perform “*INJECTOR RETURN FLOW TEST”. If okay continue.
Check for correct injectors and injector shims.
Visuslly inspect injector wire nuts and pass through connectors for damageorcorrosion.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4
4.FUEL RETURN
Check for kinked or restricted fuel return lines.
Check fuel tank venting.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 5
5.INTAKE SYSTEM
Check for inlet restriction, inspect air filter for excessive dirt/debris. Verify air intake lines are not kinked or restricted.
Check for air system leaks. Perform “*INTAKE AIR SYSTEM PRESSURE TEST - DIESEL”.
Inspect Turbocharger for wheel clearance and proper wastegate operation.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 6
6.OTHER VEHICLE SYSTEMS
Verify proper operation of the Transmission Clutch.
Verify proper operation of the Transmission.
Verify proper operation of the Vehicle brakes (check for dragging).
Verify proper operation of the Cooling fan operation cycle time.
Verify proper operation of the Engine driven accessories.
Verify proper operation of the Accelerator pedal (restricted or out of calibration).
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 7
Page 886 of 5267
7.BASE ENGINE
Inspect speed indicator ring for damaged/missing teeth.
Check for internal engine damage.
Repair Complete.
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Page 887 of 5267

*ENGINE NO START/HARD START
Possible Causes
DTC/PRODUCT IMPROVEMENT
BATTERY VOLTAGE
STARTING ACCESSORIES
ENGINE TIMING
FUEL SUPPLY SYSTEM
INJECTION SYSTEM
FUEL RETURN
AIR SYSTEM
OTHER VEHICLE SYSTEMS
BASE ENGINE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.DTC/PRODUCT IMPROVEMENT
Check for any TSB’s related to customer’s complaint or DTC’s present.
Follow appropriate guidelines in DTC troubleshooting tree or instructions in TSB.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.BATTERY VOLTAGE
Check for low battery voltage.
Is battery voltage okay?
No>>
Repair low battery voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
Ye s>>
Go To 3
3.STARTING ACCESSORIES
Inspect the Ignition switch (check for proper output voltage and/or open circuit).
Inspect the Starter.
Inspect the Grid Heaters.
Inspect the Fuel Heater.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4
Page 888 of 5267

4.ENGINE TIMING
Inspect speed indicator ring for damaged/missing teeth.
Inspect for dirty or damaged pins at Crankshaft position sensor (CKP) or Camshaft position sensor (CMP).
Verify proper overhead adjustments.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 5
5.FUEL SUPPLY SYSTEM
Verify proper fuel quality, grade and level in vehicle.
Use scan tool to monitor fuel rail pressure. If pressure does not fluctuatemore then +/- 500 psi of setpoint than the
fuel system is not the cause of the complaint. Proceed to step 6. If condition exist continue.
Verify proper low pressure supply to the Injection Pump by performing the “*IN-TANK FUEL LIFT PUMP FLOW
TEST - DIESEL” Procedure.
Use the “*HIGH PRESSURE FUEL PUMP PERFORMANCE TEST - DIESEL” to check for failed fuel pump.
Perform “*CHECKING PRESSURE LIMITING VALVE ON THE FUEL - DIESEL”.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 6
6.INJECTION SYSTEM
Perform “*INJECTOR RETURN FLOW TEST”. If okay go next step.
Check for correct injectors and injector shims.
Visuslly inspect injector wire nuts and pass through connectors for damageorcorrosion.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 7
7.FUEL RETURN
Check for kinked or restricted fuel return lines.
Check fuel tank venting.
Is vehicle repaired?
Ye s>>
Repair complete.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 8