Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2002EXPRESS 1/2 TON VAN V6-4.3L VIN WREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSTESTING AND INSPECTIONCOMPONENT TESTS AND GENERAL DIAGNOSTICSDISTRIBUTOR IGNITION (DI) SYSTEM DIAGNOSIS
2002 Chevrolet Express 1/2 Ton Van V6-4.3L VIN W
Distributor Ignition (DI) System Diagnosis
2002 Chevrolet Express 1/2 Ton Van V6-4.3L VIN WSECTION Distributor Ignition (DI) System Diagnosis
SYSTEM DESCRIPTION
This system includes the distributor, the camshaft position (CMP) sensor, the ignition coil with the ignition control (IC) module, the secondary wires, the spark plugs, the knock sensors (KS), and the crankshaft position (CKP) sensor. The ignition system is controlled by the powertrain control module (PCM). The PCM monitors the information from various engine sensors, computes the desired spark timing, and controls the dwell and firing of the ignition coil via an IC line to the IC module.
DIAGNOSTIC AIDS
Check the following when the distributor rotor does not rotate, while the engine is cranking:
^ A broken distributor drive shaft
^ A worn distributor drive gear or camshaft timing chain and gears
An intermittent may be caused by any of the following conditions:
^ A poor connection
^ Rubbed through wire insulation
^ A broken wire inside the insulation
Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs.
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
IMPORTANT: The battery should be fully charged prior to any tests.
3. This step checks for proper spark output. The spark test requires a minimum of 25,000 volts to operate. This check can be used in case of an ignition miss, because the system may provide enough voltage to run the engine but not enough to operate a spark plug under heavy load.
4. This test separates the distributor cap, rotor, and ignition wires from the ignition coil in order to help identify a secondary ignition system problem.
6. This test checks the ignition control module, connections, and wiring.
12. This test begins to determine if the PCM is providing a signal to the ignition control module. If the PCM is not providing a signal to the ignition control module, the problem exists between the ignition control module and the PCM.
14. This test checks for a basic engine mechanical problem.
This system includes the distributor, the camshaft position (CMP) sensor, the ignition coil with the ignition control (IC) module, the secondary wires, the spark plugs, the knock sensors (KS), and the crankshaft position (CKP) sensor. The ignition system is controlled by the powertrain control module (PCM). The PCM monitors the information from various engine sensors, computes the desired spark timing, and controls the dwell and firing of the ignition coil via an IC line to the IC module.
DIAGNOSTIC AIDS
Check the following when the distributor rotor does not rotate, while the engine is cranking:
^ A broken distributor drive shaft
^ A worn distributor drive gear or camshaft timing chain and gears
An intermittent may be caused by any of the following conditions:
^ A poor connection
^ Rubbed through wire insulation
^ A broken wire inside the insulation
Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs.
TEST DESCRIPTION
Steps 1-11:
Steps 12-23:
Steps 24-37:
The numbers below refer to the step numbers on the diagnostic table.
IMPORTANT: The battery should be fully charged prior to any tests.
3. This step checks for proper spark output. The spark test requires a minimum of 25,000 volts to operate. This check can be used in case of an ignition miss, because the system may provide enough voltage to run the engine but not enough to operate a spark plug under heavy load.
4. This test separates the distributor cap, rotor, and ignition wires from the ignition coil in order to help identify a secondary ignition system problem.
6. This test checks the ignition control module, connections, and wiring.
12. This test begins to determine if the PCM is providing a signal to the ignition control module. If the PCM is not providing a signal to the ignition control module, the problem exists between the ignition control module and the PCM.
14. This test checks for a basic engine mechanical problem.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.