Engine Cranks But Does Not Run. Buick LeSabre 2005

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2005 🢒 LeSabre 🢒 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 in Engine Electrical.

•	The engine cranking speed is acceptable. Refer to Engine Cranks Slowly in Engine Electrical.

•	There is adequate fuel in the fuel tank.

Step

Action

Values

Yes

Schematic Reference: Starting and Charging Schematics in Engine Electrical and Engine Controls Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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

Does the scan tool display DTC P0101, P0123, P0230, P0335, P0341, P0601, P0602 P1626, P1630, or P1631?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Go to Step 3

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 4

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 5

Go to Fuel Pump Electrical Circuit Diagnosis

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

Does the spark tester spark?

Go to Step 6

Go to Electronic Ignition (EI) System Diagnosis

Turn OFF the ignition.
Disconnect an injector connector.
Install the J 34730-405 TBI Harness Test Lamp (L36) or the J 34730-2C Injector Test Lamp (L67) to the injector connector.
Attempt to start the engine.

Does the test lamp blink while the engine is cranking?

Go to Step 7

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?

364-405 kPa (53-59 psi) VIN K

336-375 kPa (48-54 psi) VIN 1

Go to Step 8

Inspect for the following conditions:

•	Collapsed air intake duct

•	Restricted air filter element

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

•	Engine mechanical condition, worn timing chain and gears, low compression, etc.--Refer to Symptoms - Engine Mechanical in Engine Mechanical - 3.8L.

•	Restricted exhaust system--Refer to Restricted Exhaust in Engine Exhaust.

•	Stuck in range engine coolant temperature (ECT) sensor

•	Stuck manifold absolute pressure (MAP) sensor--Refer to Manifold Absolute Pressure Sensor Diagnosis .

•	Stuck throttle position (TP) sensor--Refer to DTC P0121 .

•	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 in Engine Electrical.

Also reference the Inducing Intermittent Fault Conditions and Testing for Electrical Intermittents procedures in Engine Electrical.

Did you complete the action?

Go to Step 9

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

Does the engine start and continue to operate?

Go to Step 10

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 System Check - Vehicle in Vehicle DTC Information

System OK