Engine Cranks But Does Not Run

Circuit Description
Battery voltage is applied to the ignition coils when the ignition switch is turned to the ON or START positions. The ignition control module circuitry within the coil assemblies toggles the primary windings of the ignition coil in order to induce a high voltage in the secondary windings of the ignition coil. The powertrain control module (PCM) controls the ignition event based on numerous inputs including the crankshaft position sensor. The high voltage induced in the secondary windings of the ignition coils is applied through the spark plug wires and coil boots to the spark plugs.

Diagnostic Aids
Check for any of the following conditions:
^ Check the battery condition and the engine cranking speed. The engine will not start and improper diagnosis may occur if the starting system is not operating to necessary levels.
^ Water or foreign material can cause a no start during freezing weather. The engine may start after 5 or 6 minutes in a heated shop. The malfunction may not recur until the vehicle is parked overnight in freezing temperatures.
^ Low fuel pressure can result in a very lean air/fuel mixture which may be difficult to ignite. Refer to Fuel System Diagnosis. Component Tests and General Diagnostics
^ Fouled or damaged spark plugs may cause an Engine Cranks But Will Not Run condition.
^ A vehicle that starts and runs after being brought to the shop for an Engine Cranks But Will Not Run complaint, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and wiring in order to check for an engine miss or stall.
^ Check for a malfunctioning main relay. A faulty main relay can cause no MIL and an engine that cranks but will not run. Refer to Main Relay Circuit Diagnosis. Component Tests and General Diagnostics
^ Check for a faulty IG-COIL fuse.

An intermittent malfunction may be caused by a problem in the ignition system electrical circuit. Inspect the wiring harness and components for any of the following conditions:
^ Backed out terminals.
^ Improper mating of terminals.
^ Broken electrical connector locks.
^ Improperly formed or damaged terminals.
^ Faulty terminal to wiring connections.
^ Physical damage to the wiring harness.
^ Broken conductor inside the wire insulation.
^ Corrosion of electrical connections, splices, or terminals.

Test Description
The numbers below refer to the step numbers in the Diagnostic Table.
1. The Powertrain OBD System Check prompts the technician to complete some basic checks and stores the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. The PCM relies on the CKP sensor for engine reference. Without engine reference signals there is no spark and no fuel injector pulse. A DTC P0335 sets after 3 seconds when cranking the engine if no CKP sensor signal is present.
3. The PCM relies on the CKP sensor for engine reference. Without continuous accurate reference signals, there is no reliable spark or fuel injector pulse. The scan tool engine speed display should be about 260 RPM while cranking. If erratic values, such as sudden spikes in engine speed are displayed, the engine reference signal is not stable enough for the engine to start and run properly.
4. The PCM relies on the CKP sensor for engine reference. Without continuous accurate reference signals, there is no reliable spark or fuel injector pulse. A CKP sensor Ignition Reference Low circuit that is shorted to ground will cause a faulty engine reference signal to be sent to the PCM, but will not set a CKP sensor DTC (P0335).
5. This step checks the TP sensor, the ECT sensor, and the MAP sensor for a faulty signal. A faulty sensor input to the PCM may cause a fueling condition that results in a no start.
This step checks to see if fuel system pressure is within specifications with the ignition ON and the fuel pump running. The fuel pump may be operated with the scan tool Output Control feature when the fuel level is greater than 20%.
6. This step checks for adequate secondary ignition voltage at the spark plugs.
7. This step checks to see if fuel system pressure is within specifications with the ignition ON and the fuel pump running. The fuel pump may be operated with the scan tool Output Control feature when the fuel level is greater than 20%.
13. This step checks for faulty secondary ignition wires.
15. This step checks for proper resistance of the Ignition coil secondary windings.
18. This step checks the ignition control circuit from the PCM.
19. This step checks for an ignition signal from the PCM while cranking the engine. The PCM sends a fluctuating voltage to the ignition coils after determining the engine speed from the CKP sensor.