GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2009 🢒 Vibe - FWD 🢒 Engine 🢒 Engine Controls and Fuel - 2.4L (LAX) 🢒 Engine Cranks But Does Not Run

Diagnostic Instructions
    • 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.

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 not start. This diagnostic directs the technician to the appropriate system diagnosis.

Diagnostic Aids

Inspect for any of the following conditions:

    • Insufficient fuel can cause a no start condition. The fuel gage may be inaccurate. 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, can cause a no start condition. Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) and Fuel Injector Balance Test with Special Tool.
    • 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 fuel injectors and the injector circuit are OK, and fuel spray is detected, the fuel injector ON time may be inadequate. If the powertrain control module (PCM) 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.
    • Check the crankshaft position (CKP) 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.
    • An intermittent condition of cranks but will not start or the engine quits while running can be caused by a PCM shutdown. There will be no fuel, spark, or data communications during a PCM shutdown. A short to ground in the 5-volt reference circuit of the 3-wire engine data sensors will cause a PCM shutdown. When the short to ground is absent, the PCM will operate normally with no DTCs stored. Check for a shorted throttle position (TP) or fuel tank pressure (FTP) sensor, or shorted sensor wiring.
    • Inspect the engine for good secure electrical grounds.
    • If the engine almost starts and then stalls, check for an open in the ground circuits of the CKP sensor and the camshaft position (CMP) sensor.
    • Water or foreign material in the fuel can cause a no start or engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 minutes 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.
    • A vehicle that starts and runs after being brought to the repair shop for a no start condition, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and the wiring in order to check for an engine starting or will not stay running concern.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Fuel System Description
    •  Electronic Ignition (EI) System Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

    • J 26792 Spark Tester
    • J 34730-1A Fuel Pressure Gage
    • J 34730-2B Injector Test Lamp
    • J 42982 Fuel Pressure Gage Adapter

Circuit/System Verification

Important: This diagnostic assumes the following:

   • The battery is completely charged. Refer to Battery Inspection/Test.
   • The engine cranking speed is acceptable. Refer to Engine Cranks Slowly.
   • There is adequate fuel in the fuel tank.

  1. Engine cranking for 15 seconds, observe the DTC information with a scan tool. DTCs P0100, P0102, P0103, P0115, P0117, P0118, P0120, P0122, P0123, P0220, P0222, P0223, P0335, P0339, P0340, P0351, P0352, P0353, P0354, P0562, P0563, P0601, P0604, P0606, P0607, P2610, B2799, or B279A should not set.
    2. ⇒If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  2. Verify there is no active theft deterrent system or other device that is preventing the vehicle from starting.
  3. Crank the engine and observe the scan tool ECM/Immobilizer Status parameter. The reading should be Serial Comm.
    4. ⇒If the ECM/Immobilizer Status is No Comm., test for a short to ground or a short to voltage in the powertrain control module (PCM) Immobilizer Input circuit terminal X1-11.
  4. Engine cranking, observe the scan tool Engine Speed parameter. The scan tool should indicate an engine speed greater than 0 RPM.
    5. ⇒If the engine speed is 0 RPM, refer to DTC P0335 or P0339 for further diagnosis.
  5. Turn the ignition from OFF to ON. You should hear and feel an audible click from the EFI relay in the multifunction alarm module. Repeat as necessary in order to verify EFI relay operation.
    6. ⇒If the EFI ignition relay does not click, refer to Ignition Relay Diagnosis for further diagnosis.

    Important: Perform this test on greater than 2 ignition coils.

  6. Remove the ignition coil and connect the J 26792 to the spark plug boot of the ignition coil.
  7. Connect the ignition coil electrical connector and ground the J 26792 .

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

  8. Engine cranking, verify the spark tester sparks.
    9. ⇒If there is no spark, refer to Electronic Ignition (EI) System Diagnosis.
  9. Ignition ON, command the fuel pump ON with a scan tool. You should hear the fuel pump turn ON.
    10. ⇒If the fuel pump does not turn ON, refer to Fuel Pump Electrical Circuit Diagnosis.

    Important: Perform this test on greater than 2 fuel injectors.

  10. Ignition OFF, disconnect the harness connector at the fuel injector.
  11. Connect a J 34730-2B between the fuel injector control circuit terminal 2 and the ignition 1 voltage circuit terminal 1. Engine cranking, the injector test lamp should flash.
    12. ⇒If the injector test lamp does not flash, refer to Fuel Injector Circuit Diagnosis.
  12. Ignition OFF, install the J 34730-1A and J 42982 . Refer to Fuel Pressure Gage Installation and Removal.

    13. Important: 

       • The fuel pump may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure.
       • Do NOT start the engine for this test.

  13. Ignition ON, command the fuel pump relay ON with a scan tool. Verify the fuel pressure is between 301-347 kPa (44-50 psi).
    14. ⇒If not within the specified range, refer to Fuel System Diagnosis.
  14. Verify the following conditions do not exist:
    15. • Collapsed air intake duct to the throttle body
    • Restricted air filter element
    • Spark plugs for being gas or coolant fouled--Refer to Spark Plug Inspection.
    • A skewed mass air flow (MAF) sensor--Refer to DTC P0101.
    • A skewed engine coolant temperature (ECT) sensor--Refer to Temperature Versus Resistance.
    • Exhaust system restricted--Refer to Restricted Exhaust.
    • Fuel 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 you find any of the above conditions, repair as necessary.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Spark Plug Replacement
    •  Ignition Coil Replacement