Engine Cranks But Does Not Run. Chevrolet C-Series Medium Duty Truck C6/7/8

For 1990-2009 cars

Makes 🢒 Chevrolet 🢒 2004 🢒 C-Series Medium Duty Truck C6/7/8 - Mexico 🢒 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 cranking speed is within specifications. Refer to Engine Cranks Slowly in Engine Electrical.

•	There is adequate fuel in the fuel tanks.

Diagnostic Aids

Inspect for the following conditions:

•

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

•	Faulty engine coolant temperature (ECT) sensor. Using a scan tool, compare engine coolant temperature with intake air temperature (IAT) on a completely cool engine. Engine coolant temperature should be within 3°C (5°F) of the intake air temperature.

For an intermittent condition, refer to Intermittent Conditions .

Test Description

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

This step determines if the ignition relay is providing the listed circuit breakers with voltage.

This step determines if the fuel pump is operating electrically.

Step

Action

Values

Yes

Did you perform A Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

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

Does the scan tool display DTCs P0230, P0335, P0336, P0601, P0602, P0604, P0606, P1626, P1631 or P1683?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

Turn on the ignition, with the engine off.
Probe both sides of the Eng 1 fuse with a test lamp connected to ground.

Does the test lamp illuminate on at least one side of the Eng 1 fuse?

Go to Step 4

Go to Ignition Relay Diagnosis

Turn ON the ignition, with the engine OFF.
Inspect the Eng 1 fuse for an open.

Is the fuse open?

Go to Step 11

Go to Step 5

Turn ON the ignition with the engine OFF.
Probe both sides of the following fuses with a test lamp connected to round:

•

Eng 2

•

Eng 3

Does the test lamp illuminate on at least one side of both fuses?

Go to Step 6

Go to Ignition Relay 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 7

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 8

Go to Fuel Pump Electrical Circuit Diagnosis

Turn OFF the ignition.
Install the J 34730-1A 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 (55-62 psi)

Go to Step 9

Go to Fuel System Diagnosis

Turn OFF the ignition.
Disconnect a fuel injector connector.
Install the J 34730-405 Injector Test Lamp to the injector connector.
Attempt to start the engine.

Does the test lamp flash while the engine is cranking?

Go to Step 10

Go to DTC P0200

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, low compression, etc.--Refer to Symptoms - Engine Mechanical in Engine Mechanical - 8.1L.

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

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

•	Compare MAP/BARO parameters to another vehicle. The parameters should be close in value.

Did you find and correct the condition?

Go to Step 12

Go to Diagnostic Aids

Repair the short to ground on the circuit supplied by the open fuse. Refer to Wiring Repairs in Wiring Systems.
Replace the fuse.

Did you complete the action?

Go to Step 12

Clear any DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Attempt to start the engine.

Does the engine start and continue to run?

Go to Step 13

Go to Step 2

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

System OK