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 provides an overview of each diagnostic category.

Circuit/System Description

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.

This diagnostic assumes the system voltage levels are adequate for the engine starting operation. Fuel level and fuel quality must be determined for correct diagnosis.

Diagnostic Aids

Inspect for any of the following conditions:

* Insufficient fuel can cause a no start condition. 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.
* 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 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 vehicle in good condition.
* Check the crankshaft position sensor engine reference signal with a scan tool. Observe the engine speed parameter while attempting to start the engine. The scan tool should indicate a steady 200-300 RPM during engine starting. 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.
* 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 crankshaft position sensor and the camshaft position sensor - Intake or camshaft position sensor - Exhaust.
* 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 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.
* 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 [1][2]Electrical Diagrams
Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1 A4
Description and Operation

Hybrid Modes of Operation Description Hybrid Modes of Operation Description
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 Control Module References for scan tool information
Special Tools

* CH 48027 - Digital Pressure Gauge
* EL 26792 - HEI Spark Tester
* EN 36012-A - Ignition System Diagnostic Harness
* J-34730-C - Injector Harness Tester

For equivalent regional tools, refer to Special Tools (Diagnostic Tools) Special Tools (Diagnostic Tools).

Circuit/System Verification

Note: This diagnostic assumes the following:

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

Circuit/System Testing

1. Attempt to start the engine while observing the DTC information with a scan tool. Verify that DTC P0117, P0118, P0122, P0123, P0222, P0223, P0335, P0336, P0513, P0562, P0563, P0601, P0602, P0603, P0604, P0606, P062F, P0633, P0685, P0689, P0690, P1516, P1631, P1682, P16F3, P2101, P2119, or P2610 are not set.

• If any of the DTCs listed above are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. Ignition ON, observe the Theft Deterrent LED located in the driver information center. The LED should be OFF.

• If the LED is ON, or blinking, refer to Symptoms - Theft Deterrent Symptoms - Theft Deterrent.

3. Attempt to start the engine while observing the scan tool Engine Speed parameter with a scan tool. The scan tool should indicate an engine speed greater than 0 RPM.

• If the engine speed is 0 RPM, refer to DTC P0335 or P0336 Powertrain Management.

4. Ignition ON, command the fuel pump ON with a scan tool. You should hear the fuel pump turn ON.

• If the fuel pump does not turn ON, refer to Fuel Pump Electrical Circuit Diagnosis.

5. Ignition OFF, install the CH 48027 - gauge. Refer to Fuel Pressure Gauge Installation and Removal Fuel Pressure Gauge Installation and Removal

Note:
* 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.

6. Ignition ON, command the fuel pump ON with a scan tool. The fuel pressure should be between 365-414 kPa (53-60 PSI).
7. Ignition OFF, disconnect the harness connector at a Q17 Fuel Injector.
8. Connect the J-34730-C - Injector Tester to the fuel injector harness connector
9. Ignition ON, attempt to start the engine while observing the injector tester. The injector tester should flash steadily.

• If the injector tester does not flash, refer to DTC P0201, P0202, P0203, or P0204 P0201.

• If not within the specified range, refer to Fuel System Description Fuel System Description.

Note: It may be necessary to secure the EN 36012-A - harness to the spark plug boots with electrical tape.

10. Install the EN 36012-A - harness to the spark plug boots.
11. Connect the EL 26792 - tester between the boot of a spark plug wire and ground.
12. Connect the remaining wires to the appropriate cylinders.

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

13. Attempt to start the engine while observing the spark tester. The spark tester should spark.

• If there is no spark, refer to Electronic Ignition System Diagnosis Electronic Ignition System Diagnosis.

14. Verify the following conditions do not exist:

* Air intake duct to the throttle body collapsed
* Air filter and air intake system restricted/obstructed
* Spark plugs gas or coolant fouled
* Skewed manifold absolute pressure (MAP) sensor
* Skewed engine coolant temperature (ECT) sensor
* Restricted exhaust system. Refer to Restricted Exhaust Restricted Exhaust.
* Fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis Alcohol/Contaminants-in-Fuel Diagnosis.
* Engine mechanical condition, for example, worn timing belt or low compression. Refer to Symptoms - Engine Mechanical Symptoms - Engine Mechanical.

• If you find any of the above conditions, repair as necessary.

Repair Verification

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

Spark Plug Replacement Service and Repair