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

The engine cranks but does not run is an organized approach to identify a condition which causes the engine to crank but not start. This diagnostic directs the technician to the appropriate system diagnosis.

Inspect for any of the conditions listed below:

• If equipped with a key type ignition system, a partially retracted or folded over ignition key. When attempting to start the engine, the mechanical portion of the vehicle key must be locked in the fully extended position with the fob parallel to the key. Leaving the key partially retracted or folded over when starting may interrupt transponder authentication and result in an intermittent no-start condition. In such instances, DTC B3055 may also be set. If an intermittent no-start complaint is received, it may be necessary to discuss with the customer their starting habits and verify they are locking the key in the fully extended position, fob parallel to the key, before starting.
• A crankshaft position sensor condition. Check the crankshaft position sensor engine reference signal with a scan tool. Observe the Engine Speed parameter while cranking the engine. The scan tool should indicate a steady 200–300 RPM while cranking. If erratic values, such as sudden spikes in the engine speed, are displayed, the engine reference signal is not stable enough for the engine to start and run properly.
• Insufficient fuel. Thoroughly inspect the fuel delivery system for sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.
• Fuel injectors with partially blocked and restricted nozzles, or a malfunctioning solenoid. Refer to Fuel Injector Diagnosis for diagnosis.
• Fuel injector ON time inadequate. When this condition is present, there may be fuel spray at the fuel injectors and the indicated fuel pressure may be correct, yet there may not be enough fuel to start the engine. If the engine control module (ECM) receives incorrect inputs from the various information sensors, the fuel delivered by the fuel injectors may be inadequate to start the engine. Check all the engine data parameters with a scan tool and compare the values indicated with the expected values or the values from a known good vehicle.
• Loose unsecured engine electrical grounds. Inspect the engine for good secure electrical grounds.
• Water or foreign material in the fuel, which can cause either a no start or a engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 min in a heated repair shop. The malfunction may not recur until parked overnight in freezing temperatures. Extreme weather conditions can cause contaminated fuel to prevent the vehicle from starting.
• An ignition system that is susceptible to moisture. If the engine starts and runs after being brought into a warm, dry repair shop, the ignition system may be susceptible to moisture. Spray water on the ignition system components and wiring while cranking the engine in order to check for an engine starting or will not stay running concern.
• If the engine almost starts and then stalls, check for an open in the ground circuits of the crankshaft position sensor and the camshaft position sensor – Intake or camshaft position sensor – Exhaust.

Engine Controls Schematics

Master Electrical Component List

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Control Module References for scan tool information

• EL 26792 HEI Spark Tester

For equivalent regional tools, refer to Special Tools.

1. Crank the engine for up to 15 s.
2. Verify that DTC P0117, P0118, P0122, P0123, P0222, P0223, P0335, P0336, P0513, P0562, P0563, P0601, P0602, P0603, P0604, P0606, P062F, P0633, P0641, P0651, P0685, P0689, P0690, P0697, P06A3, P06D2, P1516, P1631, P1682, P16F3, P2101, P2119, or P2610 is not set.
• If any of the DTCs are set

  Refer to Diagnostic Trouble Code (DTC) List - Vehicle.

• If none of the DTCs are set
3. Ignition ON.
4. Verify the security indicator on the instrument cluster illuminates momentarily.
• If the indicator stays ON or is flashing

  Review the Diagnostic Trouble Code (DTC) List - Vehicle for Immobilizer system DTCs. For additional information, refer to Immobilizer Description and Operation .

• If the indicator does not stay ON and is not flashing
5. Verify the scan tool Engine Speed parameter displays greater than 0 RPM while cranking the engine.
• If 0 RPM

  Refer to DTC P0335 or P0336.

• If greater than 0 RPM
6. Connect the EL 26792 HEI Spark Tester between the boot of a spark plug wire and ground.

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

7. Verify the spark tester sparks while cranking the engine.
• If the spark tester does not spark

  Refer to Electronic Ignition System Diagnosis.

• If the spark tester sparks
8. Ignition ON.

Note:

• If the engine is too hot, high fuel pressure readings may result due to hot soak fuel boiling. Allow the engine coolant temperature to cool to less than 60° C (150° F) before attempting to verify fuel pressure.
• The Fuel Pump Enable may need to be commanded On a few times in order to obtain the highest possible fuel pressure.
• Additional DTCs may set when using the fuel pump output control.

9. Command the Fuel Pump Enable On several times with a scan tool.
10. Verify the scan tool Fuel Pressure Sensor parameter is between 345–650 kPa (50–94 PSI) with the fuel pump running.
• If not within the specified range

  Refer to Fuel System Diagnosis.

• If within the specified range
11. Verify the scan tool Fuel Pressure Sensor parameter, after the fuel pump has turned OFF, decreases to less than 600 kPa (87 PSI) and does not decrease greater than 34 kPa (5 PSI) in 1 minute.
• If not within the specified range

  Refer to Fuel System Diagnosis.

• If within the specified range
12. Verify the conditions listed below do not exist:
• Collapsed air intake duct to the throttle body
• Air filter and air intake system for restrictions and obstructions
• Spark plugs for being gas or coolant fouled
• A skewed manifold absolute pressure (MAP) sensor
• A skewed engine coolant temperature (ECT) sensor
• Test the exhaust system for restrictions. Refer to Restricted Exhaust.
• Test the fuel for contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis.
• Engine mechanical condition, for example, worn timing belt or low compression. Refer to Symptoms - Engine Mechanical.
• If a condition exists

  Repair as necessary.

• If no conditions exist
13. All OK.

Perform the Diagnostic Repair Verification after completing the repair.