Driveability - Diesel - Non-Dtc Based Diagnostics Jeep Grand Cherokee WK2

CHECKING THE ENGINE MECHANICAL SYSTEMS

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .

POSSIBLE CAUSES

DIAGNOSTIC TEST

1. CHECKING ENGINE MECHANICAL NOTE: The following items should be checked as a possible cause of a Driveability or No-Start problem. WARNING: Do not attempt to remove or separate high pressure fuel lines. Failure to follow these instructions may result in possible serious or fatal injury. Engine Valve Timing - must be within specification. Engine Compression - must be within specifications. Camshaft Lobes - check for abnormal wear. Camshaft Position Sensor - check the camshaft position sensor tooth for debris and deterioration. Crankshaft Position Sensor - check the crankshaft tone wheel for debris and deterioration. Engine Exhaust System - must be free of any restriction. Engine Drive Chains and Sprockets - must be properly positioned. Vacuum System - must operate properly and be free of any vacuum leaks. Fuel - must have adequate supply and must be free of contamination (ie. debris, water and gasoline). Fuel Injectors - must not be plugged or restricted. Fuel Lift Pump - must operate properly (where applicable). Fuel Injection Pump - must be producing the correct output volume and pressure. Inspect the Fuel Lines, Fuel Filter and Fuel Pressure Relief Valve for signs of restriction and leaks. NOTE: Check for any Technical Service Bulletins that may relate to the problem. Are there any problems evident? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Test Complete.

CHECKING THE FUEL DELIVERY SYSTEM

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .

1. VISUAL INSPECTION NOTE: For best results, perform Fuel Delivery System test with vehicle at room temperature. Extreme cold temperatures can cause inaccurate results. NOTE: Make sure that the vehicle has at least 1/8 of a tank of fuel before proceeding with this test. Perform a visual inspection of the fuel system for any signs of a fuel leak. Were any visual signs of a leak detected? Yes Repair as necessary Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 2 .
2. CHECKING SENSOR VALUES WITH THE SCAN TOOL Turn the ignition on, engine not running. With the scan tool, perform the following checks: Check and compare the values of the Ambient Air Temperature Sensor, Coolant Temperature Sensor and Fuel Temperature Sensor with the key on. The values should read approximately equal on a cold engine. Check and compare the values of the Air Inlet Pressure Sensor, Boost Pressure Sensor and Exhaust Differential Pressure Sensor. The sensors should read approximately the same. Check the plausibility of the Accelerator Pedal Position sensors. If possible, start the engine and check the following: Check the cam/crank synchronization during cranking. Partially open and close the throttle slowly a few times and check and compare the MAF Sensor actual reading against the MAF Sensor set point. Check the plausibility of the temperature and pressure sensors. NOTE: If the engine does not start, disregard these checks. Are the cam and crank synchronized and the sensors reading normal? Yes Go To 3 . No Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
3. SCAN TOOL TEST Perform the following tests with the scan tool: Injector Quantity Correction for each injector. Look for an injector that is reading noticeably different than the others indicating a faulty injector. Compression Test. The RPM drop in each cylinder should be approximately equal. Do any of the cylinders or injectors indicate a problem as compared to the others during the scan tool tests? Yes Evaluate the results of the scan tool tests. If any of the cylinders are found to be performing poorly as compared to the others, check for engine mechanical issues on the suspect cylinder and repair as necessary. If no mechanical issues are found with the engine, Go To 4 . No Go To 5 .
4. CHECK THE FUEL INJECTOR SUPPLY Turn the ignition off. Remove the High Pressure Supply Line to the Fuel Injector of the cylinder that indicated a problem and check the line for a restriction. NOTE: Do not crank the engine with the line off. Is the Fuel Injector supply line restricted? Yes Replace the Fuel Injector supply line and perform the scan tool test again. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Using the wiring diagram as a guide, check the resistance of the Fuel Injector circuits from the injector to the PCM. If the resistance is above 2.0 Ohms, repair the circuit for high resistance and perform the scan tool tests again. If the resistance was below 2.0 Ohms for both circuits, replace the Fuel Injector in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
5. COMPARE THE FUEL PRESSURE ACTUAL READING AGAINST FUEL PRESSURE SET POINT (TARGET) With the scan tool, select and add the fuel rail pressure actual to a graph. With the scan tool, select and add the fuel rail pressure set point (target) to a graph. Select merge graphs. NOTE: For best results when viewing the graphs, set the time increment on the graph to 2.0 seconds and the pressure range to 400 bar (5800 psi) for cranking and idle checks. Change the pressure range to 1600 bar (23, 200 psi) before performing the snap acceleration. The Fuel Pressure reading should closely mirror the Fuel Pressure Set point reading. While observing the Fuel Pressure Actual reading and the Fuel Pressure Set point on the graph, start the engine and then allow it to idle. After the idle RPM steadies, perform a snap acceleration. The minimum fuel rail pressure needed to start the engine is 120 bar (1740 psi) However, on a normally operating system, the fuel pressure will typically spike up instantly and peak at approximately 310 bar (4496 psi) during cranking. After starting the engine will typically settle to about 280 bar (4061 psi) at idle. The spec. for minimum fuel rail pressure at idle is 230 bar (3336 psi). During snap acceleration the pressure reading will typically spike up to between approximately 1500 bar - 1550 bar (21, 756 psi - 22, 481 psi). Select the conclusion that best matches the result of the test: The Fuel Pressure reading appears to mirror close to the Fuel Pressure Set point reading during cranking, idle, and snap acceleration: Go To 6 . The Fuel Pressure actual reading does not peak during cranking, pressure is too low (below set point) at idle: If the vehicle is a no start , Go To 10 . If the vehicle starts and runs , Go To 11 . The Fuel Pressure actual reading does not peak during cranking, pressure appears normal (mirrors set point) at idle: Go To 18 . The Fuel Pressure reading is too high: Go To 7 . The Fuel Pressure reading is oscillating excessively above and below the Fuel Pressure Set point reading: Install a clear tube in-line in the fuel supply side, as close to the High Pressure Delivery Pump as possible. Check for signs of air bubbles in the fuel supply system. If air bubbles are present, repair the leak causing the air bubbles getting into the supply side system. If no air bubbles are present, Go To 11 . Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
6. CHECKING FUEL QUALITY/CONTAMINATION Collect a fuel sample from the vehicle in a clean see through container. Collect a fuel sample of fresh clean fuel in a clean, transparent container for reference. Check the vehicle's fuel sample for the following: Check the color of the fuel. Diesel fuel will generally be a yellow color. Allow the fuel to settle and look for cloudiness indicating contamination. Check the volatility of the fuel. Look for a parting line in the fuel sample indicating another type of liquid mixed with the fuel. Look for any signs of debris in the fuel sample. Were any problems found? Yes Refer to the service information to replace the fuel in the entire fuel system. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No At this time, the fuel system appears to be operating normally. Check for any Service Bulletins that may apply. It may be necessary to test drive the vehicle under various load conditions while monitoring the fuel pressure actual and target graphs. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
7. CHECK THE SUPPLY SIDE FUEL SYSTEM PRESSURE Turn the ignition off. Disconnect the quick connect fitting at the Fuel Filter outlet line and connect (special tool #8978A, Decay Tool, Fuel) in-line. Crank the engine or start the engine and observe the reading on the fuel pressure gauge. Turn the ignition off. NOTE: The fuel pressure specification is between 4.0 bar (58.0 psi) and 5.9 bar (85.6 psi). Is the fuel pressure above the listed specifications? Yes If the pressure is reading 8 bar (116 psi) or below, check for a restriction in the line between the Fuel Filter and the HPDP. If no restriction is found, replace the High Pressure Delivery Pump and retest the system. If the pressure is reading above 8 bar (116 psi), replace the Fuel Lift Pump. Check for a restriction in the line between the quick connect fitting and the HPDP. If no restriction is found in the system, replace the High Pressure Delivery Pump. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 8 .
8. CHECKING FOR A RESTRICTION IN THE FUEL RETURN NOTE: A leak in the return system due to a hose being off or split could a good indication of a restriction in the fuel return system. Look downstream of the leak for the restriction. Remove the fuel pressure gauge. Reconnect the quick connect fitting at the Fuel Filter outlet line. Disconnect the fuel return hose at the High Pressure Delivery Pump (HPDP) or at the Fuel Rail. Connect a fuel pressure gauge in-line. While observing the fuel pressure gauge, start the engine and allow it to come to idle. NOTE: If there are no restrictions, the return pressure should be below 1.0 bar (14.5 psi). Is the return pressure above 3.5 bar (50.76 psi)? Yes Go To 9 . No Check for high pressure in the fuel supply side. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
9. CHECKING FUEL RETURN LINE FOR A RESTRICTION Remove the fuel pressure gauge. Disconnect the fuel return line at the Fuel Lift Pump. Blow regulated shop air through the return line and check for a restriction. Was the return line restricted? Yes Repair the restriction in the fuel return line. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Check for a Fuel Quantity Solenoid that may be sticking in the open position or Fuel Pressure Regulator that may be sticking in the closed position and repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
10. CHECK THE FUEL RAIL PRESSURE SENSOR Disconnect the Fuel Rail Pressure Sensor harness connector. Attempt to start the engine. Does the engine start and run? Yes Using the wiring diagram as a guide, check the resistance of the Fuel Rail Pressure Sensor circuits between the Fuel Rail Pressure Sensor and the PCM. If the resistance is above 2.0 Ohms on any circuit, repair the circuit for high resistance. If the circuits measure below 2.0 Ohms, replace the Fuel Rail Pressure Sensor in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 11 .
11. CHECK THE SUPPLY SIDE FUEL SYSTEM PRESSURE AND VOLUME Turn the ignition off. Disconnect the quick connect fitting at the Fuel Filter outlet line and connect (special tool #8978A, Decay Tool, Fuel) in-line. With the scan tool, actuate the Fuel Lift pump and observe the reading on the fuel pressure gauge. Open the valve to the measuring bottle and collect fuel for 15 seconds. Close the valve to the measuring bottle. Turn the ignition off. NOTE: The fuel pressure specification is between 4.0 bar (58.0 psi) and 5.9 bar (85.6 psi). NOTE: The fuel volume specifications is a minimum of 0.75 liters for 15 seconds. Is the fuel pressure and volume within the listed specifications? Yes, and vehicle is a no start: Go To 16 . Yes, and vehicle starts and runs: Go To 18 . No, pressure and/or volume reading is below specification: Go To 12 . No, pressure reading is above specification: If the pressure is reading 8 bar (116 psi) or below, check for a restriction in the line between the Fuel Filter and the HPDP. If no restriction is found, replace the High Pressure Delivery Pump and retest the system. If the pressure is reading above 8 bar (116 psi), replace the Fuel Lift Pump and repair the restriction in the line between the quick connect fitting and the HPDP or replace the High Pressure Delivery Pump if no restriction is found and retest the system. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
12. CHECK THE SUPPLY PRESSURE AND VOLUME AT FUEL FILTER HOUSING INLET Turn the ignition off. Remove the (special tool #8978A, Decay Tool, Fuel) from the Fuel Filter outlet line. Reconnect the fuel line. Disconnect the quick connect fitting at the Fuel Filter inlet line. Connect the (special tool #8978A, Decay Tool, Fuel) and check the fuel supply pressure and volume at the inlet side of the Fuel Filter housing using the same method. Is the fuel pressure and volume within the listed specifications? Yes Replace the Fuel Filter in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 13 .
13. CHECK THE FUEL LIFT PUMP MAXIMUM OUTPUT With the scan tool, actuate the Fuel Lift pump and temporarily close the valve blocking fuel flow. Observe the pressure gauge reading. CAUTION: Do not block the line for more than a few seconds or damage to the Fuel Lift Pump can occur. The pressure should spike up and then stabilize at approximately 116 psi (8 bar) in two or three seconds. Does the fuel pressure spike up and stabilize at approximately 8 bar (116 psi) when the valve is closed? Yes Replace the High Pressure Delivery Pump in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 14 .
14. CHECK THE VOLTAGE DROP OF THE FUEL PUMP MOTOR CIRCUITS Turn the engine off. Reconnect the fuel lines. NOTE: The Fuel Lift Pump Module harness connector should remain connected to the pump during this test step in order to accurately measure the voltage drop. Using a voltmeter, back probe the Fuel Pump Motor Feed circuit with the positive lead of the meter at the Fuel Lift Pump Module harness connector. Back probe the Fuel Lift Pump Ground circuit with the negative lead of the meter at the Fuel Lift Pump Module harness connector. CAUTION: Use only approved back probe tools when back probing a connector so as not to cause damage to the terminals or insulation of the connector. Damage to the terminals can cause poor terminal contact or retention. Damage to the insulation can introduce corrosion due to water infiltration. Turn the ignition on. With a scan tool, actuate the Fuel Lift Pump control to ON (100%). NOTE: The voltage should read the same as battery voltage if there is no resistance in the circuit. Is the voltage reading the same as battery voltage +/- 0.2 volt? Yes Check the supply line between the Fuel Lift Pump and the Fuel Filter inlet for a restriction. If the line is not restricted, replace the Fuel Lift Pump in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 15 .
15. CHECK THE VOLTAGE DROP IN THE FUEL PUMP MOTOR FEED CIRCUIT Turn the engine off. Remove the negative lead of the meter from the Fuel Lift Pump harness connector and connect the lead to a good battery ground. NOTE: The Fuel Lift Pump Module harness connector should remain connected. Turn the ignition on. With a scan tool, actuate the Fuel Lift Pump control to ON (100%). Measure the voltage of the Fuel Pump Motor Feed circuit at the Fuel Lift Pump harness connector. Is the voltage reading the same as battery voltage +/- 0.2 volt? Yes Repair the Fuel Lift Pump Ground circuit for an open circuit or high resistance. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Repair the Fuel Pump Motor Feed circuit for an open circuit or high resistance. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
16. STATIC FUEL INJECTOR LEAK BACK CHECK Turn the ignition off. Pull up on the center locking tab and disconnect the fuel return hoses at the Fuel Injectors. Connect the Bosch Injector Return Flow Meter or equivalent to all of the Fuel Injectors. Crank the engine for 15 seconds. Turn the ignition off. Evaluate the individual return quantities. NOTE: For an accurate test result, all of the injectors must be measured at the same time for comparison. The maximum allowable injector leak back from any injector is three times the amount collected for the injector with the lowest measured amount (E.G. If the injector with the smallest amount collected is 10 ml, then any injector with more than 30 ml is considered faulty and should be replaced). Is the return quantity collected from any of the Fuel Injectors more than three times the Fuel Injector with lowest return quantity collected? Yes Replace the Fuel Injector or Fuel Injectors that were over specification. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 17 .
17. STATIC PRESSURE REGULATOR LEAK BACK CHECK Disconnect the fuel return line at the Fuel Rail return fitting (next to the Fuel Pressure Regulator). Cap the end of the fuel return line to keep debris from entering the system and fuel from leaking out. Connect a hose to the end of the Fuel Rail. Place the end of the hose into a measurement bottle. Crank the engine for 10 seconds. Turn the ignition off. Measure the quantity of fuel that was collected from the Fuel Rail. NOTE: The Fuel Pressure Regulator should be closed during cranking and very little or no fuel should be present. Is the quantity of fuel collected from the Fuel Pressure Regulator below 10.0 ml? Yes Replace the High Pressure Delivery Pump in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Using the wiring diagram as a guide, check the resistance of the Fuel Pressure Regulator circuits. If the resistance is above 2.0 Ohms, repair the high resistance in the wiring. If the resistance is below 2.0 Ohms, replace the Fuel Rail Assembly in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
18. DYNAMIC FUEL INJECTOR LEAK BACK CHECK Turn the ignition off. Pull up on the center locking tab and disconnect the fuel return hoses at the Fuel Injectors. Install the Bosch Injector Return Flow Meter or equivalent to the Fuel Injectors. Start the engine and allow it to idle for 30 seconds or until one of the measuring containers is full. Turn the ignition off. Evaluate the individual return quantities. NOTE: For an accurate test result, all of the injectors must be measured at the same time for comparison. The maximum allowable injector leak back from any injector is three times the amount collected for the injector with the lowest measured amount (E.G. If the injector with the smallest amount collected is 10 ml, then any injector with more than 30 ml is considered faulty and should be replaced). Is the return quantity collected from any of the Fuel Injectors more than three times the Fuel Injector with lowest return quantity collected? Yes Replace the Fuel Injector that was over specification. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 19 .
19. DYNAMIC PRESSURE REGULATOR LEAK BACK CHECK Turn the ignition off. Disconnect the fuel return line at the Fuel Pressure Regulator. Cap the end of the fuel return line to keep debris from entering the system and fuel from leaking out. Connect a hose to the end of the Fuel Rail return fitting (next to the Fuel Pressure Regulator). Place the hose into a measurement bottle. Start the engine and allow it to idle for 10 seconds. Turn the ignition off. Measure the quantity of fuel collected in the bottle. Is the quantity of fuel collected below 30.0 ml? Yes Replace the High Pressure Delivery Pump in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Using the wiring diagram as a guide, check the resistance of the Fuel Pressure Regulator circuits. If the resistance is above 2.0 Ohms, repair the high resistance in the wiring. If the resistance is below 2.0 Ohms, replace the Fuel Rail Assembly in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .

1. PCM GROUND CIRCUIT(S) OPEN Turn the ignition off. Disconnect the PCM C1 harness connector. Using a 12-volt test light connected to 12-volts, probe each of the PCM ground circuits in PCM C1 connector cavities 2, 4 and 6. Did the test light illuminate for each cavity? Yes Go To 2 . No Repair the PCM Ground circuit(s) for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
2. FUSED IGNITION SWITCH START/RUN OUTPUT CIRCUIT OPEN Turn the ignition off. Turn the ignition to the Start position. Using a 12-volt test light connected to ground, check the (F942) Fused Ignition Run/Switch Output circuit at the PCM C1 harness connector (cavity 54). Turn the ignition to the Run position. Using a 12-volt test light connected to ground, check the (F942) Fused Ignition Run/Switch Output circuit at the PCM C1 harness connector (cavity 54). Is the test light on for both ignition switch positions? Yes Go To 3 . No Repair the (F942) Fused Ignition Run/Switch Output circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
3. CHECKING THE ASD RELAY SYSTEM Turn the ignition off. Connect a jumper between ground and the (K51) ASD Relay Control circuit in PCM C1 harness connector (cavity 28) to close the relay. Turn the ignition on. Using a 12-volt test light connected to ground, probe the (F342) and (F344) ASD Relay Output circuits at the PCM C1 harness connector (cavities 1, 3 and 5). Does the test light illuminate brightly for each circuit? Yes Test Complete. No Go To 4 .
4. FUSED ASD RELAY BATTERY SUPPLY CIRCUIT OPEN Turn the ignition off. Remove the ASD Relay. Using a 12-volt test light connected to ground, probe the Fused ASD Relay Battery Supply circuit at ASD Relay connector (terminal 30). Does the test light illuminate brightly? Yes Go To 5 . No Repair the Fused ASD Relay Battery Supply circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
5. ASD RELAY OUTPUT CIRCUIT OPEN Connect a jumper between cavity 30 and cavity 87 at the ASD Relay connector. Using a 12-volt test light connected to ground, probe the (F342) and (F344) ASD Relay Output circuits at the PCM C1 harness connector (cavities 1, 3 and 5). Did the test light illuminate for each circuit? Yes Go To 6 . No Repair the (F342) or (F344) ASD Relay Output circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
6. ASD RELAY CONTROL CIRCUIT OPEN Turn the ignition off. Remove the ASD Relay. Measure the resistance of the (K51) ASD Relay Control circuit between the ASD Relay connector and the PCM C1 harness connector. Is the resistance below 5.0 Ohms? Yes Replace the ASD Relay. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Repair the ASD Relay Control circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .

ENGINE CRANKS BUT WILL NOT START

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .

1. PCM CODES PRESENT NOTE: The PCM must have proper power and ground connections for the following tests to be valid. Refer to «CHECKING THE PCM POWER AND GROUND CIRCUITS»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#driveability-diesel-non-dtc-based-diagnostics) . Turn the ignition on. Using the scan tool, read the PCM DTCs. Does the scan tool display any PCM DTCs? Yes Perform the appropriate diagnostic procedure. Refer to «DIAGNOSTIC CODE INDEX»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-diagnostic-code-index) . No Go To 2 .
2. VEHICLE SECURITY CODES PRESENT With the scan tool, read the WIN DTCs. Does the scan tool display any WIN DTCs? Yes Perform the appropriate diagnostic procedure. Refer to «DIAGNOSIS AND TESTING»(/jeep/grand-cherokee/wk2-2010-2013/remont/door-locks-anti-theft-systems/#wireless-ignition-node-win-electrical-diagnostics) . No Go To 3 .
3. CHECK FOR INTAKE SYSTEM LEAKS OR RESTRICTIONS Turn the ignition off. Make sure vehicle has adequate fuel supply in fuel tank. Carefully inspect all air intake and Turbocharger related hoses/tubes and connections for leaks. Inspect the air filter for excessive dirt, soiling or other problems that may cause restricted air flow. Were any problems found? Yes Repair or replace as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 4 .
4. ECT SENSOR Using a temperature probe, check the vehicle temperature near the ECT Sensor. Turn the ignition on. With the scan tool in Sensors, read the ECT Sensor temperature. Compare the temperature probe reading with the scan tool reading. Are the two readings within 10°C of each other? Yes Go To 5 . No Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
5. GLOW PLUGS NOTE: Prior to performing this test, be sure to check the Glow Plug Relay operation. Check the Glow Plugs for proper operation. Are the Glow Plugs operating properly? Yes Go To 6 . No Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
6. FUEL SYSTEM RESTRICTION Inspect the fuel system lines for restrictions, leaks or other problems. Is there any evidence of problems? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 7 .
7. FUEL CONTAMINATION Inspect the fuel supply for contamination. Is the fuel contaminated? Yes Drain and replace the contaminated fuel in the system. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 8 .
8. CHECK FUEL PRESSURE AT ENGINE CRANKING Using the scan tool, read the Fuel Pressure Sensor signal while cranking the engine. Does the Fuel Pressure Sensor signal increase to above 3500 psi (240 bar) within a few seconds after engine cranking begins? Yes Go To 9 . No Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. Refer to «CHECKING THE FUEL DELIVERY SYSTEM»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#driveability-diesel-non-dtc-based-diagnostics__checking-the-fuel-delivery-system) . Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
9. CRACKED OR BROKEN FLEX PLATE Use the service information to gain access to and inspect for a broken or cracked flex plate. Were any problems found? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 10 .
10. ENGINE DRIVE CHAINS Refer to the service information and make sure the Engine Drive Chain is installed correctly and the camshaft and crankshaft gears are timed correctly. Were any problems found? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Replace and program the Powertrain Control Module in accordance with the service information. Refer to «MODULE, POWERTRAIN CONTROL , REMOVAL»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) . Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .

ENGINE WILL NOT CRANK

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .

Scheme 31

Scheme 32

1. BATTERY CABLES Turn the ignition off. NOTE: The battery must be fully charged before diagnosing a no crank condition. Turn the ignition off. Inspect the battery cables for corrosion, looseness or other problems. Is there evidence of problems? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 2 .
2. BATTERY CABLE HIGH RESISTANCE Using the service information, check the battery cables for high resistance. Did either battery cable have a voltage drop greater than 0.2 volt? Yes Replace the battery cable(s). Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 3 .
3. WIN CODES PRESENT Turn the ignition on. Using the scan tool, read the WIN DTCs. Does the scan tool display any WIN related DTCs? Yes Perform the appropriate diagnostic procedure. Refer to «DIAGNOSIS AND TESTING»(/jeep/grand-cherokee/wk2-2010-2013/remont/door-locks-anti-theft-systems/#wireless-ignition-node-win-electrical-diagnostics) . No Go To 4 .
4. CHECKING STARTER OPERATION Turn the ignition off. Remove the Starter Relay from the TIPM. WARNING: THE TRANSMISSION MUST BE IN NEUTRAL AND THE PARK BRAKE MUST BE SET FOR THIS TEST. WARNING: THE ENGINE MAY CRANK IN THE NEXT STEP. WHEN THE ENGINE IS CRANKING, 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. Momentarily jumper Starter Relay connector cavities 30 and 87 in the TIPM connector. Did the engine crank? Yes Go To 5 . No Go To 10 .
5. STARTER RELAY Install a substitute relay in place of the Starter Relay. Attempt to start the engine. Does the engine crank? Yes Replace the Starter Relay. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 6 .
6. CHECK POWER AND GROUNDS Perform the CHECKING THE PCM POWER AND GROUND test procedure. Refer to «CHECKING THE PCM POWER AND GROUND CIRCUITS»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#driveability-diesel-non-dtc-based-diagnostics) . Were any problem found with the PCM powers and grounds? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 7 .
7. (F942) OPEN IGNITION SW START/RUN CIRCUIT Turn the ignition off. Disconnect the PCM C1 harness connector. Remove the Starter Relay. Using a 12-volt test light connected to ground, probe the Ignition (F942) Switch Start/Run Output circuit at the PCM C1 harness connector while turning the ignition switch to the START position. Does the test light illuminate with the ignition switch in the START position? Yes Go To 8 . No Repair the (F942) Ignition Switch Output circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
8. (T752) STARTER RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE Turn the ignition off. Disconnect the PCM C1 harness connector. Remove the ASD Relay. Using a jumper wire, connect ASD Relay connector cavities 30 and 87. Turn the ignition on. Measure the voltage of the (T752) Starter Relay Control circuit at the Starter Motor Relay connector. Is the voltage above 1.0 Volt? Yes Repair the (T752) Starter Relay Control circuit for a short to voltage. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 9 .
9. (T752) STARTER RELAY CONTROL CIRCUIT OPEN Turn the ignition off. Remove the jumper wire and install the ASD relay. Measure the resistance of the (T752) Starter Relay Control circuit between the PCM harness connector and the Starter Relay connector in the PDC. Is the resistance below 5.0 Ohms? Yes Replace the Powertrain Control Module in accordance with the service information. Refer to «MODULE, POWERTRAIN CONTROL , REMOVAL»(/jeep/grand-cherokee/wk2-2010-2013/remont/communication-devices/#electronic-control-modules-service-information) . Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Repair the (T752) Starter Relay Control circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
10. OPEN FUSED BATTERY (+) CIRCUIT Using a 12-volt test light connected to ground, check the Fused B+ circuit in the Starter Relay connector. Is the test light on? Yes Go To 11 . No Repair the Fused B(+) circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
11. (T750) STARTER RELAY OUTPUT CIRCUIT OPEN Disconnect the (T750) Starter Relay Output wire from the Starter Solenoid. Connect the (T750) Starter Relay Output wire (at the Starter) to ground. Using a 12-volt test light connected to 12-volts, check the (T750) Starter Relay Output circuit at the Starter Relay connector. Does the test light illuminate brightly? Yes Go To 12 . No Repair the (T750) Starter Relay Output circuit for an open. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
12. MECHANICAL PROBLEM Turn the ignition off. Attempt to manually rotate the crankshaft 360°. Is the crankshaft able to rotate 360°? Yes Replace the Starter Motor in accordance with the service information. Refer to «STARTER , REMOVAL»(/jeep/grand-cherokee/wk2-2010-2013/remont/starter/#starting-service-information) . Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Repair the engine mechanical problem. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .

LACK OF ENGINE POWER

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article .

1. CHECKING FOR PCM DTCS Turn the ignition on. With the scan tool, read the PCM DTCs. Are there any DTCs present? Yes Perform the appropriate diagnostic procedure. Refer to «DIAGNOSTIC CODE INDEX»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-diagnostic-code-index) . No Go To 2 .
2. FUEL SYSTEM LEAK Turn the ignition off. WARNING: High Pressure fuel lines deliver diesel fuel under extreme pressure from the injection pump to the fuel injectors. This may be as high as 23, 200 PSI (1600 BAR). Use extreme caution when inspecting for high pressure fuel leaks. Failure to follow these instructions may result in possible serious or fatal injury. WARNING: Fuel under this amount of pressure can penetrate skin causing possible serious or fatal injury. Inspect for high pressure fuel leaks with a sheet of cardboard. Wear safety goggles and adequate protective clothing when servicing fuel system. Failure to follow these instructions may result in possible serious or fatal injury. Inspect the entire fuel system for leakage. Is there any evidence of leakage? Yes Repair as necessary in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 3 .
3. FUEL SYSTEM CONTAMINATION NOTE: Mixing any other fuels such as gasoline or kerosine can cause this symptom to occur. Turn the ignition off. Inspect the fuel system for contamination. Is the fuel contaminated? Yes Repair as necessary in accordance with the service information. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 4 .
4. CHECKING BOOST PRESSURE Turn the ignition on. NOTE: This test requires two people. One person to test drive the vehicle while a technician observes the scan tool readings. With the scan tool in Sensors, read and compare the Boost Pressure (PSI) with the Boost Pressure Desired/Setpoint (PSI) while test driving the vehicle under various load conditions such as idle, hard acceleration, and cruise. NOTE: The Boost Pressure reading should directionally follow (trail) the Boost Pressure Desired/Setpoint reading. Does the Boost Pressure reading follow the Boost Pressure Desired/Setpoint reading? Yes Go To 5 . No Go To 11 .
5. CHECKING FUEL PRESSURE Turn the ignition on. NOTE: This test requires two people. One person to test drive the vehicle while a technician observes the scan tool readings. With the scan tool in Sensors, read and compare the Fuel Pressure (PSI) with the Fuel Pressure Desired/Setpoint (PSI) while test driving the vehicle under various load conditions such as idle, hard acceleration, cruise and deceleration. NOTE: The Fuel Pressure reading should directionally follow (trail) the Fuel Pressure Desired/Setpoint reading. Does the Fuel Pressure reading directionally follow the Fuel Pressure Desired/Setpoint reading? Yes Go To 6 . No Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. Refer to «CHECKING THE FUEL DELIVERY SYSTEM»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#driveability-diesel-non-dtc-based-diagnostics__checking-the-fuel-delivery-system) . Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
6. INJECTOR QUANTITY ADJUSTMENT NOTE: Each Fuel Injector is labeled with a code. This code determines the injector quantity adjustment. Each Injector code must be programmed into the PCM using the scan tool. Turn the ignition off. Refer to the service information to locate each fuel injector label and check for the correct code for each fuel injector in the PCM. Are all of the injector codes correct? Yes Go To 7 . No Using the scan tool, program the correct Fuel Injector code into the PCM. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .
7. ENGINE COMPRESSION Start and idle the engine. With the scan tool, perform the Cylinder Compression Test. Does the Cylinder Compression Test indicate low compression in any of the cylinders? Yes Using the service information, repair the engine as necessary to regain proper cylinder compression. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 8 .
8. FUEL INJECTOR NOTE: An injector that sticks open can cause this symptom. A sticking injector will cause the engine to miss fire and emit excessive black smoke from the exhaust system. Start and idle the engine. With the scan tool, perform the Cylinder Fuel Quantity Correction Test. NOTE: A problem injector will be indicated by a significant change in correction quantity as compared to the rest of the injectors. Are any of the injectors displaying a significant amount of injection quantity correction? Yes 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 the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 9 .
9. CRACKED OR BROKEN FLEX PLATE Use the service information to gain access to and inspect for a broken or cracked flex plate. Were any problems found? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 10 .
10. ENGINE DRIVE BELT/CHAIN Refer to the service information to ensure the Engine Drive Belt/Chain is installed correctly and the camshaft and crankshaft gears are timed correctly. Were any problems found? Yes Repair as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Test Complete.
11. CHECK FOR INTAKE AND EXHAUST SYSTEM RESTRICTIONS Turn the ignition off. Inspect the exhaust system for damaged components that could cause exhaust flow blockage. Inspect all air intake, crankcase vent and turbocharger related hoses/tubes and connections for damage, air leaks or blockage. Inspect the air filter for excessive dirt, soiling or other problems that may cause restricted air flow. Were any problems found? Yes Repair or replace as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Go To 12 .
12. CHECKING FOR AIR LEAKS NOTE: Inspect all air intake and turbocharger related tubes for damage, restriction or poor connection. Any of these conditions can cause a poor performance/lack of power symptom. Turn the ignition off. Connect the (special tool #8404B, Kit, EELD And Accessory) to the intake system where possible and begin injecting smoke into the system. Observe all intake system components for evidence of smoke leakage. Is there evidence of smoke leakage? Yes Repair or replace as necessary. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) . No Check for proper linkage connection between the Boost Pressure Servo Motor and the Turbocharger assembly. Repair or replace as necessary. If OK, refer to the service information and replace the Turbocharger assembly. Perform the PCM VERIFICATION TEST. Refer to «PCM VERIFICATION TEST»(/jeep/grand-cherokee/wk2-2010-2013/remont/testing-diagnostics/#30l-diesel-intermittent-dtc-pcm-verification-test-pcmecmtcm-programming-pre-diagnostic-troubleshooting-procedure) .

See also:
• PCM VERIFICATION TEST
• DIAGNOSTIC CODE INDEX
• DIAGNOSIS AND TESTING
• MODULE, POWERTRAIN CONTROL , REMOVAL
• STARTER , REMOVAL
• CHECKING THE PCM POWER AND GROUND CIRCUITS
• CHECKING THE FUEL DELIVERY SYSTEM