GM Service Manual Online
For 1990-2009 cars only

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 in Engine Electrical.
    • There is adequate fuel in the tank.
    • There is proper compression.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

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Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

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

Is DTC P0230, P0336, P0341, P0601, or P0602 set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Test both sides of each of the following fuses with a test lamp connected to ground.
  3. • Fuel Injectors
    • ABS/PCM
    • Fuel pump relay fuse
    • DFI Module

Does the test lamp illuminate on both sides of each fuse?

--

Go to Step 5

Go to Step 4

4

Visually inspect the fuses for which the test lamp did not illuminate on both sides.

Is any fuse open?

--

Go to Step 14

Go to Ignition Relay Diagnosis

5

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the MIL.

Is the MIL illuminated?

--

Go to Step 6

Go to Step 13

6

  1. Monitor the Engine RPM parameter while the engine is cranking, with a scan tool.
  2. Attempt to start the engine.

Does the Engine RPM parameter display cranking RPM?

--

Go to Step 7

Go to Electronic Ignition (EI) System Diagnosis

7

Command the fuel pump relay ON with a scan tool.

Does the fuel pump run?

--

Go to Step 8

Go to Fuel Pump Electrical Circuit Diagnosis

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 relay ON with a scan tool.

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

364-405 kPa (53-59 psi)

Go to Step 9

Go to Fuel System Diagnosis

9

  1. Turn OFF the ignition.
  2. Disconnect a fuel injector connector.
  3. Install the J 34730-405 Fuel Injector Test Lamp to the fuel injector connector.
  4. Attempt to start the engine.

Does the test lamp blink while the engine is cranking?

--

Go to Step 11

Go to Step 10

10

  1. Remove the J 34730-405 from the fuel injector connector.
  2. Turn ON the ignition, with the engine OFF.
  3. Probe the ignition 1 voltage supply circuit of the fuel injector with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to DTC P0341

Go to Fuel Injector Circuit Diagnosis

11

  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.

Does the spark tester spark?

--

Go to Step 12

Go to Electronic Ignition (EI) System Diagnosis

12

Inspect for the following conditions:

    • A collapsed air intake duct
    • A restricted air filter element--Refer to Air Cleaner Element Replacement .
    • Fouled spark plugs--Refer to Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition.
    • Engine mechanical condition such as a worn timing chain and gears, low compression, etc.--Refer to Engine Compression Test in Engine Mechanical.
    • Restricted exhaust system--Refer to Restricted Exhaust in Engine Exhaust.
    • Faulty engine coolant temperature (ECT) sensor
    • Faulty MAP sensor--Refer to Manifold Absolute Pressure Sensor Diagnosis .
    • Stuck throttle position (TP) sensor

Did you complete the action?

--

Go to Step 17

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13

Test the ignition 1 voltage circuit between the ABS/PCM fuse in the junction block-left I/P and the powertrain control module (PCM) for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

14

  1. Isolate the excessive current draw in the circuit or the component supplied by the open fuse. Refer to Circuit Testing in Wiring Systems.
  2. Repair the short to ground in the circuit or replace the component as necessary.
  3. Refer to Wiring Repairs in Wiring Systems.

  4. Replace the open fuse.

Did you complete the repair or replacement?

--

Go to Step 17

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15

Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 16

16

Replace the PCM. Refer to Powertrain Control Module Replacement

Did you complete the replacement?

--

Go to Step 17

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17

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

Does the engine start and continue to operate?

--

Go to Step 18

Go to Step 2

18

  1. Allow the engine to idle until normal operating temperature is reached.
  2. Observe the DTC Information with a scan tool.

Are any DTCs displayed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK