Engine Cranks But Does Not Run. GMC Truck GMC C Sierra

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 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 within specification. Refer to Engine Cranks Slowly in Engine Electrical.

•	There is adequate fuel in the fuel tank.

Diagnostic Aids

Check for the following conditions:

•

The mass air flow (MAF) is compared to a calculated mass air flow based upon the manifold absolute pressure (MAP), the throttle position (TP), and the engine RPM. A skewed or unresponsive MAP sensor at key ON will cause the predicted air flow value to be inaccurate. Compare the MAP and TP readings to that of a known good vehicle.

•	Check for a faulty engine coolant temperature (ECT) sensor. Use a scan tool in order to compare the ECT with the intake air temperature (IAT) on a completely cooled engine. The ECT should be within 3°C (5°F) of the IAT.

•	For an intermittent condition, refer to Intermittent Conditions .

Test Description

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

It may be necessary to connect a battery charger to the battery for this step. If the battery state of charge is low, the scan tool may reset during the cranking test.

This step tests the ignition relay for proper operation. The ignition relay supplies voltage to the injectors and the ignition coils. When the ignition relay is not operating properly, a no start condition occurs. If the test lamp does not illuminate, this indicates the ignition relay is not supplying a voltage to the fuses.

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

Crank the engine for the specified amount of time.

Does the scan tool display any DTCs that failed this ignition?

15 seconds

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

Check the body control module (BCM) for DTCs related to the vehicle theft deterrent (VTD) system.

Does the scan tool display any BCM VTD DTCs?

Go to Diagnostic System Check - Theft Deterrent in Theft Deterrent

Go to Step 4

Monitor the engine speed while cranking the engine.

Is engine RPM indicated on the scan tool?

Go to Step 5

Go to Electronic Ignition (EI) System Diagnosis

Turn ON the ignition, with the engine OFF.
Probe both sides of the fuses located in the underhood electrical center listed below using a test lamp connected to ground.

•

INJR A

•

INJR B

•

ECM I

Does the test lamp illuminate on both sides of the fuses?

Go to Step 6

Go to Ignition Relay Diagnosis

Monitor the engine coolant temperature (ECT) using the scan tool.

Is the ECT on the scan tool close to the actual engine temperature?

Go to Step 7

Go to DTC P0118

Enable the fuel pump using the scan tool.

Does the fuel pump operate?

Go to Step 8

Go to Fuel Pump Electrical Circuit Diagnosis

Turn OFF the ignition.
Install a fuel pressure gauge. Refer to Fuel Pressure Gage Installation and Removal .

Important: The fuel pump operates for about 2 seconds when the ignition is turned ON. The fuel pressure must be observed when the fuel pump is operating.

Turn ON the ignition, with the engine OFF.
Observe the fuel pressure while the fuel pump is operating.

Is the fuel pressure within the specified range?

379-427 kPa (55-62 psi)

Go to Step 9

Go to Fuel System Diagnosis

Perform the following additional inspections:

•	Inspect the duct work between the mass air flow (MAF) sensor and the throttle body for air leaks.

•	Inspect that the throttle angle is at 0 percent at a closed throttle. If the throttle angle is not at 0 percent , refer to DTC P0122 or DTC P0123 .

•

A malfunctioning MAF sensor may cause a no start or a stall after a start. If you suspect this, disconnect the MAF sensor. The PCM will default to the speed density in order to calculate the engine load and the intake 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 .

•	Inspect the spark plugs for being gas fouled. Refer to Spark Plug Inspection .

•	Inspect for an engine mechanical failure that causes an engine not to start such as timing chain, low compression. Refer to Engine Compression Test in Engine Mechanical 4.8L, 5.3L, 6.0L.

•	Compare the manifold absolute pressure (MAP)/barometric pressure (BARO) parameters to another vehicle. The parameter values should be close to each other.

Did you find and correct the condition?

Go to Step 10

Go to Hard Start

Select the Diagnostic Trouble Codes (DTC) option and the Clear DTC Information option using the scan tool.
Attempt to start the engine.

Does the engine start and continue to run?

Go to Step 11

Go to Step 2

Idle the engine at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option using the scan tool.

Are any DTCs displayed?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 12

Select the Capture Info option and the Review Info option using the scan tool.

Are any DTCs displayed that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK