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
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:
* 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.
* The engine control module (ECM) uses the camshaft position sensors to determine engine speed and position when there is a crankshaft position sensor condition.
* The engine will operate with a crankshaft position sensor condition only if the ECM has stored the learned reference position of the camshafts in memory. With a crankshaft position sensor condition in the signal circuit, the engine will go into a limp home mode after a hard restart. The ECM then calculates engine speed from one of the camshaft position sensors.
* The fuel pump flow control module controls and monitors the operation of the in-tank fuel pump. If the fuel pump flow control module detects a fault, a DTC sets in the fuel pump flow control module. The fuel pump flow control module will then send a serial data message to the engine control module (ECM) requesting the illumination of the malfunction indicator lamp (MIL).
* The fuel injectors are calibrated to begin operating when the fuel rail pressure reaches 2 MPa (290 psi) at 20-32°C (68-90°F). This specification will vary when the temperature is outside of this range.
* 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. Refer to Fuel Injector Solenoid Coil Test Fuel Injector Solenoid Coil Test.
* 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 good vehicle.
* Inspect the engine for good secure electrical grounds.
* 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 A/C Compressor Clutch
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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
CH-48027 - Digital Pressure Gauge
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. Refer to Battery Inspection/Test Battery Inspection/Test.
* The engine cranking speed is acceptable. Refer to Engine Cranks Slowly Testing and Inspection.
* There is adequate fuel in the fuel tank.
1. Engine cranking, observe the DTC information with a scan tool. Verify that DTC P0116, P0118, P0335, P0336, P0513, P0601, P0602, P0603-P0606, P062B, P0627, P0628, P0629, P0633, P069E, P1631, P1649, or U0109 does not set.
• If any of the listed DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
2. Ignition ON, observe the Security Indicator on the instrument cluster. The security indicator should illuminate momentarily and then go out.
• If the security indicator stays ON or is flashing, review the scan tool DTC information for Immobilizer system DTCs-Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle. For additional information, refer to Immobilizer Description and Operation Immobilizer.
3. Engine cranking, observe the scan tool Engine Speed parameter. The scan tool should indicate an engine speed greater than 0 RPM.
• If the engine speed is 0 RPM, refer to DTC P0335 (LF1, LFW, or LFX) P0335 and DTC P0336 (LF1, LFW or LFX) P0336.
Note: A MAF sensor circuit condition may cause an Engine Cranks But Does Not Run condition without setting a DTC.
4. Engine cranking, observe the scan tool Mass Airflow Sensor parameter. The parameter should display greater than 0 Hz.
• If the parameter is not the specified value, refer to DTC P0102 or P0103 P0102 for further diagnosis.
5. Test the ignition system for spark-Refer to Electronic Ignition System Diagnosis Electronic Ignition (EI) System Diagnosis.
6. Ignition OFF, all accessories OFF, install a CH-48027 - digital pressure gauge-Refer to Fuel Pressure Gauge Installation and Removal Fuel Pressure Gauge Installation and Removal.
7. Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool. Verify the fuel pressure is between 345-690 kPa (50-100 psi) while the fuel pump is running.
• If the fuel pump runs but the pressure is not the specified value, refer to Fuel System Diagnosis Fuel System Diagnosis.
• If the fuel pump does not run, refer to Fuel Pump Electrical Circuit Diagnosis Fuel Pump Electrical Circuit Diagnosis.
Note: Allow the vehicle to stabilize at an ambient temperature between 20-32° C (68-90° F) before performing the following step.
8. Engine cranking, observe the Fuel Rail Pressure Sensor parameter with a scan tool. The parameter should be between 1.9-2.1 MPa (279-305 psi).
• If not the specified value, refer to DTC P0090-P0092, P00C8, P00C9, or P00CA P0090.
9. Verify that the following conditions do not exist:
* Collapsed air intake duct to the throttle body
* Restricted air filter element
* Gas or coolant fouled spark plugs
* A skewed engine coolant temperature (ECT) sensor-Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor Temperature Versus Resistance - Engine Coolant Temperature Sensor.
* Restricted exhaust system-Refer to Restricted Exhaust Restricted Exhaust.
* Contaminated fuel-Refer to Alcohol/Contaminants-in-Fuel Diagnosis Testing and Inspection.
* An engine mechanical condition, for example, worn timing chain and gears, low compression-Refer to Symptoms - Engine Mechanical Symptoms - Engine Mechanical.
• If you find any of the above conditions, repair as necessary.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.