Engine Cranks But Does Not Run. Cadillac STS 2005

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 Engine 🢒 Engine Electrical 🢒 Engine Cranks But Does Not Run

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 within specifications. Refer to Engine Cranks Slowly in Engine Electrical.

•	There is adequate fuel in the fuel tank.

Diagnostic Aids

•	The engine control module (ECM) uses the camshaft position (CMP) sensors to determine engine speed and position when there is a crankshaft position (CKP) sensor condition.

•

The engine will operate with a CKP sensor condition only if the ECM has stored the learned reference position of the camshafts in memory. With a CKP sensor condition other than a short to voltage 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 CMP sensors. During a limp home mode, the following additional DTCs may set and should be ignored:

-	DTC P0324 Knock Sensor (KS) Module Performance

-	DTC P1011 Intake Camshaft Position Actuator Park Position Bank 1

•	A short to voltage in the signal circuit of the CKP sensor will cause the engine to stall or not start and a DTC will not set.

•	Refer to Symptoms - Engine Controls and Hard Start for further diagnosis.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This step determines if there is a DTC causing the no start condition.

This step determines if the fuel pump is turning ON. An audible sound can be heard at the fuel injector rail when the fuel pump is turned ON.

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

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

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Crank the engine over for 15 seconds.
Turn ON the ignition, with the engine OFF.
Observe the Engine DTC information with a scan tool.

Does the scan tool display DTC P0118, P0201-P0206, P0335, P0336, P0337, P0338, P0351-P0356, P0601, P0602, P0604, P0606, P0627, P0628, P0629, P1629, P1630, P1631, or P2105?

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

Go to Step 3

Observe the Theft Deterrent DTC Information with a scan tool.

Does the scan tool display any Theft Deterrent DTCs?

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

Go to Step 4

Important: Additional DTCs may set when using the fuel pump output control.

With a scan tool, command the fuel pump ON.

Does the fuel pump turn ON?

Go to Step 5

Go to Fuel Pump Electrical Circuit Diagnosis

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?

380-410 kPa (55-60 psi)

Go to Step 6

Go to Fuel System Diagnosis

Inspect for the following conditions:

•	A short to voltage in the signal circuit of the crankshaft position (CKP) sensor will cause the engine to stall or not start and a DTC will not set. Refer to DTC P0335 .

•	Collapsed air intake duct between the mass air flow (MAF) sensor and the throttle body

•	Restricted air filter element

•	Test for water or alcohol contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

•	Spark plugs for being gas or coolant fouled--If the spark plugs are fouled, determine what caused the condition, refer to the following procedures:

-	Spark Plug Replacement

-	Spark Plug Inspection

•	Inspect for a malfunctioning MAF sensor causing a no start or a stall after a start. If this condition is suspected, use the following procedure:

-	Disconnect the MAF sensor. The engine control module (ECM) will ignore the MAF sensor and default to the calculated air flow.

-	If disconnecting the MAF sensor corrects the condition and the connections are OK, replace the MAF sensor. Refer to Mass Airflow Sensor/Intake Air Temperature Sensor Replacement .

•	Engine mechanical condition, for example, worn timing chain and gears, low compression--Refer to Symptoms - Engine Mechanical in Engine Mechanical - 3.6L (LY7).

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

•	The engine coolant temperature (ECT) sensor is NOT close to the actual engine temperature. Refer to DTC P0125 .

Did you complete the action?

Go to Step 7

With a scan tool, clear the DTCs.
Attempt to start the engine.

Does the engine start and continue to operate?

Go to Step 8

Go to Step 2

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

Are there any DTCs that have not been diagnosed?

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

System OK