Engine Cranks But Does Not Run. Buick LaCrosse 2005

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2005 🢒 LaCrosse 🢒 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 Engine Cranks Slowly .

•	There is adequate fuel in the fuel tank

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

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

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

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

Does the scan tool display DTC P0101, P0230, P0335, P0340, P0601, P0602, P0604, P0606, P0685, P1626, P1630, or P1631?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

Turn ON the ignition, with the engine OFF.
Probe both sides of the fuel INJ fuse and the ELEK IGN fuse with a test lamp connected to a good ground.

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

Go to Step 4

Go to Powertrain Relay Diagnosis

Attempt to start the engine.
Observe the engine speed parameter while the engine is cranking with a scan tool.

Does the engine speed parameter display cranking RPM?

Go to Step 5

Go to Electronic Ignition (EI) System Diagnosis

Command the fuel pump ON, with a scan tool.

Does the fuel pump turn ON?

Go to Step 6

Go to Fuel Pump Electrical Circuit Diagnosis

Turn OFF the ignition.
Disconnect a spark plug wire.
Install the J 26792 HEI Spark Tester to the spark plug wire.
Attempt to start the engine.

Does the spark tester spark?

Go to Step 7

Go to Electronic Ignition (EI) System Diagnosis

Turn OFF the ignition.
Disconnect an injector connector.
Install a J 34730-2C Injector Test Lamp to the fuel injector connector.
Attempt to start the engine.

Does the test lamp blink while the engine is cranking?

Go to Step 8

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

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

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

384-425 kPa (56-62 psi)

Go to Step 9

Go to Fuel System Diagnosis

Inspect for the following conditions:

•	A collapsed air intake duct

•	A restricted air filter element--Refer to Air Cleaner Element Replacement .

•	The spark plugs for being gas or coolant fouled--Refer to Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition.

•	An engine mechanical condition such as worn timing chain and gears, or low compression, etc.--Refer to Symptoms - Engine Mechanical and Engine Compression Test .

•	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 .

Did you complete the action?

Go to Step 10

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

Does the engine start and continue to operate?

Go to Step 11

Go to Step 2

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

Are any DTCs displayed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK