GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Generic 🢒 2005 🢒 Unit Repair 🢒 Engine 🢒 Engine Electrical 🢒 Engine Cranks But Does Not Run

Circuit Description

The Engine Cranks But Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks But Does Not Run diagnostic table directs the service technician to the appropriate system diagnosis.

The Engine Cranks But Does Not Run diagnostic table assumes the following:

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

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the DTC information with a scan tool.

Does the scan tool display DTCs P0201-P0206, P0230, P0335, P0340, P0601, P0602, P0604, P0606, P0685, P1518, P1626, P1630, or P1631?

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Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3
  1. Turn ON the ignition with the engine OFF.
  2. Probe both sides of the ETC fuse with a test lamp connected to a good ground.

Does the test lamp illuminate on at least one side of the fuse?

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Go to Step 4

Go to Powertrain Relay Diagnosis

4
  1. Attempt to start the engine.
  2. Observe the engine RPM parameter while the engine is cranking with a scan tool.

Does the engine RPM parameter display cranking RPM?

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Go to Step 5

Go to Crankshaft Position Sensor System Diagnosis

5

Command the fuel pump ON, with a scan tool.

Does the fuel pump turn ON?

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Go to Step 6

Go to Fuel Pump Electrical Circuit Diagnosis

6
  1. Turn OFF the ignition.
  2. Disconnect a spark plug wire.
  3. Install the J 26792 Spark Tester to the spark plug wire.
  4. Attempt to start the engine.
  5. Repeat this procedure for the remaining cylinders.

Does the spark tester spark for all cylinders?

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Go to Step 7

Go to Electronic Ignition (EI) System Diagnosis

7
  1. Turn OFF the ignition.
  2. Disconnect an injector connector.
  3. Install a J 44603 Injector Test Lamp to the fuel injector connector.
  4. Attempt to start the engine.

Does the test lamp blink while the engine is cranking?

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Go to Step 8

Go to DTC P0201, P0202, P0203, P0204, P0205, or P0206

8
  1. Turn OFF the ignition.
  2. Install the J 34730-1A Fuel Pressure Gage. Refer to Fuel Pressure Gage Installation and Removal .
  3. Turn ON the ignition, with the engine OFF.
  4. Command the fuel pump ON with a scan tool.

Is the fuel pressure within the specified range while the fuel pump is operating?

348-425 kPa (50.47-61.64 psi)

Go to Step 9

Go to Fuel System Diagnosis

9

Inspect for the following conditions:

    • A collapsed air intake duct
    • A restricted air filter element
    • The spark plugs for being gas or coolant fouled--Refer to Spark Plug Inspection .
    • An engine mechanical condition such as worn timing chain and gears, or low compression, etc.
    • A restricted exhaust system--Refer to Restricted Exhaust .
    • An engine coolant temperature (ECT) sensor that has shifted in value--Refer to Temperature Versus Resistance .
    • A faulty manifold absolute pressure (MAP) sensor--Refer to Manifold Absolute Pressure Sensor Diagnosis .
    • Loose or unseated mass air flow (MAF) sensor connector--Loose terminals or connector not fully seated may allow erratic MAF sensor signals. Refer to Testing for Proper Terminal Contact in Testing for Intermittent Conditions and Poor Connections .

Did you complete the action?

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Go to Step 10

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10
  1. Clear the DTCs with a scan tool.
  2. Attempt to start the engine.

Does the engine start and continue to operate?

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Go to Step 11

Go to Step 2

11
  1. Idle the engine.
  2. Allow the engine to reach operating temperature.
  3. Observe the DTC information with a scan tool.

Are any DTCs displayed?

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Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK