Engine Cranks But Does Not Run

Engine Cranks But Does Not Run

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provide an overview of each diagnostic category.

Circuit/System Description

This Engine Cranks but Does Not Run diagnostic is an organized approach to identify a condition which causes the engine to crank but does not continue to run. This diagnostic directs the service technician to the appropriate system diagnosis. This diagnostic assumes the vehicle system voltage levels are adequate for starter motor operation. Refer to Battery Inspection/Test (Component Tests and General Diagnostics) and Engine Cranks Slowly (Engine Cranks Slowly). The fuel level supply must be adequate, and the fuel quality must be able to sustain the combustion process.

Diagnostic Aids

* When disconnecting electrical connectors or removing fuses and relays from a fuse block, always inspect both mating electrical terminals for corrosion and terminal tightness.
* Use the J 35616 for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness terminals.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

* Component Connector End Views (Connector Views)
* Electrical Center Identification Views (Application and ID)

Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information
Special Tools

* J 35616 Connector Test Adapter Kit
* J 34730-1A Fuel Pressure Gauge

Circuit/System Verification

Attempt to start the engine. The engine should start and run.

If the vehicle passes the Circuit/System Verification test, then refer to Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections).

Circuit/System Testing

1. Crank the engine while observing the scan tool Vehicle DTC Information.

• If any of the following DTCs are set, diagnose these first: DTC P0117, P0118, P0122, P0123, P0201-P0208, P0222, P0223, P0335, P0336, P0351-P0358, P0513, P0562, P0563, P0601-P0604, P0606, P0607, P062F, P0633, P0685, P0690, P1516, P1631, P1682, or P2610. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

2. With the ignition ON and the engine OFF, test the fuses that are supplied ignition 1 voltage by the powertrain relay. The test lamp should illuminate ON for each test point of the fuses.

• If the test lamp does not illuminate on, for at least one test point of each fuse, refer to DTC P0685, P0689, or P0690 (P0685).

3. Crank the engine while observing the scan tool engine speed parameter.

• If engine RPM is not indicated, refer to DTC P0335 (P0335) or DTC P0336 (P0336).

4. Install a spark plug tester onto one ignition module/coil assembly, on each bank of the engine.

Note: An erratic or weak spark is considered a no spark condition.

5. Crank the engine while observing both spark plug testers. Both spark plug testers should spark.

• If spark is not observed, is inconsistent, or weak on either spark plug tester, refer to Electronic Ignition System Diagnosis (Electronic Ignition System Diagnosis).

6. With the ignition ON and the engine OFF, command the fuel pump ON and OFF with the scan tool. The fuel pump should energize when commanded ON, and de-energize when commanded OFF.

• If the fuel pump does not turn ON and OFF, refer to Fuel System Diagnosis (Without FPCM) (Testing and Inspection)Fuel System Diagnosis (FPCM) (Component Tests and General Diagnostics).

7. Turn OFF the ignition.
8. Install the J 34730-1A Fuel Pressure Gauge. With the ignition ON and the engine OFF, command the fuel pump ON several times with the scan tool. Refer to Fuel System Diagnosis (Fuel System Diagnosis) for the fuel pressure specification.
9. Inspect for the following conditions:

* Compare the actual engine coolant temperature to the ECT parameter
* Filter and air intake system for restrictions and obstructions
* Test the fuel for contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool) (Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool))Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool) (Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)).
* Inspect the spark plugs-Refer to Spark Plug Inspection (Testing and Inspection).
* Test the exhaust system for restrictions-Refer to Restricted Exhaust (Restricted Exhaust).
* Engine mechanical conditions, such as worn timing chain, sprocket gears, low compression, etc-Refer to Symptoms - Engine Mechanical (Symptoms - Engine Mechanical).

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.