Service Information

Orlando

Fuel Injector Circuit Diagnosis

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Ignition voltage - fuse to splice	1	2	-	-
Ignition voltage - splice to injector	1	P0201 00, P0202 00, P0203 00, P0204 00	-	-
Control (fuel injector 1)	P0201 00	P0201 00	P0262 00	-
Control (fuel injector 2)	P0202 00	P0202 00	P0265 00	-
Control (fuel injector 3)	P0203 00	P0203 00	P0268 00	-
Control (fuel injector 4)	P0204 00	P0204 00	P0271 00	-
1. Open fuse, cranks no start 2. Cranks no start

The engine control module (ECM) enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The ECM controls each fuel injector by grounding the control circuit via a solid state device called a driver.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL 35616-E GM-Approved Terminal Test Kit Includes J 35616-200 Test Light Probe Kit

For equivalent regional tools, refer to Special Tools .

Circuit/System Testing

Ignition OFF, disconnect the harness connector at the appropriate fuel injector listed below:

•	Q17A Fuel Injector 1

•	Q17B Fuel Injector 2

•	Q17C Fuel Injector 3

•	Q17D Fuel Injector 4

Ignition ON, verify that a test lamp illuminates between the appropriate Q17 Fuel Injector ignition circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the Q17 Fuel Injector.

Ignition OFF, connect a J 35616-200 Test Light Probe Kit between the K20 Engine Control Module control circuit terminal B and the ignition circuit terminal A of each Q17 Fuel Injector one at a time.
Engine cranking, the test lamp should flash for each injector.

⇒	If the test lamp is always ON, test the appropriate K20 Engine Control Module control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

⇒	If the test lamp is always OFF, test the appropriate K20 Engine Control Module control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

If all circuits test normal, test or replace the appropriate Q17 Fuel Injector. Refer to Fuel Injector Diagnosis : Scan Tool → Special Tool .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Fuel Injector Replacement

•	Control Module References