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 to not start. The diagnostic table directs the service technician to the appropriate system diagnosis. The diagnostic table assumes the following conditions are met:

•	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: 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

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

Does the scan tool display DTCs P0102, P0113, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0261, P0264, P0267, P0270, P0273, P0276, P0279, P0282, P0335, P0336, P0601, P0602, P0604, P0606, P0628, P0629, P0686, P0687, P0689, P0690, P1626, P1631, or P1636?

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

Go to Step 3

Does the scan tool display any body control module (BCM) vehicle theft deterrent (VTD) DTCs?

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

Go to Step 4

Turn ON the ignition, with the engine OFF.
Probe both test points of the V8 ECM fuse located in the underhood electrical center using a test lamp connected to a good ground.

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

Go to Step 5

Go to Powertrain Relay Diagnosis

Observe the engine speed parameter on the scan tool, while cranking the engine.

Does the scan tool display 0 RPM?

Go to Step 9

Go to Step 6

Turn OFF the ignition.
Remove the ignition coil assembly from either bank. DO NOT disconnect any electrical connectors from the ignition coil assembly. Refer to Ignition Coil Replacement - Bank 1 or Ignition Coil Replacement - Bank 2 .
Install the J 36012-A Ignition Diagnostic Harness.
Install the J 26792 Spark Tester on one of the spark plug jumper wires.
Attach the clamp end of the spark tester to a good ground.
Crank the engine with the remaining spark plug jumper wires connected.
Repeat steps 5-7 for each remaining cylinder on this bank.
Repeat the procedure for the opposite bank.
Reassemble the vehicle after performing the procedure.

Did the spark tester spark on all cylinders?

Go to Step 7

Go to Electronic Ignition (EI) System Diagnosis

Important: The engine coolant temperature (ECT) must be below the operating temperature in order to avoid irregular fuel pressure readings due to hot soak fuel boiling.

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

Important: The fuel pump may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.

Command the fuel pump ON with a scan tool.
Observe the fuel pressure while the fuel pump is operating.

Is the fuel pressure within the specified range?

380-410 kPa

(55-60 psi)

Go to Step 8

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 .

•	Fouled spark plugs--Refer to Spark Plug Replacement and Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition.

•	Contaminated fuel--Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

•	An engine mechanical condition, for example, broken timing chain, low compression--Refer to Setting Camshaft Timing and Engine Compression Test in Engine Mechanical.

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

•	An ECT sensor that has shifted in value--Refer to Temperature Versus Resistance .

•	Proper operation of the MAP sensor--Refer to DTC P0106 .

Did you complete the action?

Go to Step 15

Turn ON the ignition with the engine OFF.
Test for a short between the mass air flow (MAF) sensor 12-volt reference circuit and the following circuits:

•	The intake air temperature (IAT) 5-volt reference circuit

•	The IAT low reference circuit

•	Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition.

Go to Step 15

Go to Step 10

Disconnect a camshaft position sensor.
Install a DMM between the camshaft position sensor 12-volt reference circuit and a good ground.
Monitor the DMM while disconnecting the MAF/IAT sensor.
If the voltage changes while disconnecting the MAF/IAT sensor, replace the MAF/IAT sensor.

Did you replace the sensor?

Go to Step 15

Go to Step 11

Disconnect the MAF sensor.
Install a DMM between the MAF sensor 12-volt reference circuit and a good ground.
Monitor the DMM while disconnecting all other sensors connected to the 12-volt reference circuit, one at a time.
If the voltage changes when one of the sensors are disconnected, replace the sensor.

Did you replace a sensor?

Go to Step 15

Go to Step 12

Test the 12-volt reference circuits of the following components for a short to ground. Refer to Circuit Testing in Wiring Systems.

•	MAF/IAT airflow sensor

•	Crankshaft position (CKP) Sensor

•	CMP sensor bank 1 (right) exhaust

•	CMP sensor bank 2 (left) exhaust

•	CMP sensor bank 1 (right) Intake

•	CMP sensor bank 2 (left) Intake

Did you find and correct the condition?

Go to Step 15

Go to Step 13

Test for shorted terminals and poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 14

Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 15

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

Does the engine start and continue to operate?

Go to Step 16

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