Engine Cranks But Does Not Run: Description

The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine to not start. The diagnostic table directs the service technician to the appropriate system diagnosis. The diagnostic table assumes the following conditions are met:

The battery is completely charged. Refer to Battery Inspection/Test (Non-HP2) in Engine Electrical.
The engine cranking speed is acceptable. Refer to Engine Cranks Slowly in Engine Electrical.
There is adequate fuel in the fuel tank.

Engine Cranks but Does Not Run

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Turn ON the ignition, with the engine OFF. Observe the DTC information with a scan tool. Does the scan tool display DTCs P0101, P0108, P0230, P0335, P0336, P0601, P0602, P0604, P0606, P0607, P0641, P0651, P0685, P0689, P0690, P1621, P1630, P1631, P1682, or P2610?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	Go to Step 3
3	Does the scan tool display any body control module (BCM) or vehicle theft deterrent (VTD) DTCs?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	Go to Step 4
4	Turn ON the ignition, with the engine OFF. Probe both sides of the fuses located in the underhood electrical center listed below using a test lamp connected to ground. ENG 1 fuse O2A fuse O2B fuse TAC fuse INJ A INJ B Does the test lamp illuminate on at least one side of each fuse?	-	Go to Step 5	Go to Powertrain Relay Diagnosis
5	Command the fuel pump ON with a scan tool. Does the fuel pump operate?	-	Go to Step 6	Go to Fuel Pump Electrical Circuit Diagnosis
6	Turn OFF the ignition. Disconnect a spark plug wire. Install J 26792 Spark Tester. Attempt to start the engine. Does the spark tester spark?	-	Go to Step 7	Go to Electronic Ignition (EI) System Diagnosis
7	Turn OFF the ignition. Install a fuel pressure gage. Refer to Fuel Pressure Gage Installation and Removal . IMPORTANT: You may need to command the fuel pump ON a few times to obtain the highest possible fuel pressure. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Observe the fuel pressure while the fuel pump is operating. Is the fuel pressure within the specified range?	379-427 kPa (55-62 psi)	Go to Step 8	Go to Fuel System Diagnosis
8	Inspect for the following conditions: Collapsed air intake duct Restricted air filter element-Refer to Air Cleaner Element Replacement . Spark plugs for being fouled-Refer to Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition, for example, broken timing chain, low compression-Refer to Engine Compression Test in Engine Mechanical - 5.3L. Restricted exhaust system-Refer to Restricted Exhaust in Engine Exhaust An Engine Coolant Temperature (ECT) sensor that has shifted in value-Refer to Temperature vs Resistance . Compare the MAP parameter to another vehicle. The parameters should be close in value. Refer to DTC P0106 . Did you complete the action?	-	Go to Step 9	Go to Hard Start
9	Clear the DTCs with a scan tool. Attempt to start the engine. Does the engine start and continue to operate?	-	Go to Step 10	Go to Step 2
10	Idle the engine. Allow the engine to reach operating temperature. Observe the DTC information with a scan tool. Are any DTCs displayed?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK