LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2004 >> Century Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls 3.1L (Troubleshooting & Diagnosis) >> Engine Controls >> Fuel Injector Circuit Diagnosis >> Test Description

Test Description

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

  1. 4:  This step tests for a short to ground on the ignition 1 voltage supply circuit of the fuel injector.
  2. 5:  This step tests for a short to a PCM ground on the ignition 1 voltage supply circuit of the fuel injector.
  3. 6:  This step tests for an open between the multi-way connector and the fuel injectors.
  4. 7:  This step tests for an open or high resistance between the multi-way connector and the fuel injectors.
Fuel Injector Circuit Diagnosis

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Inline Harness Connector End Views  in Wiring Systems,  Engine Controls Component Views  , or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 Are any fuel injector DTCs set? - Go to DTC P0201-P0206 Go to Step 3 
3 Inspect the fuel injector fuse.
Is the fuel injector fuse open?
- Go to Step 4  Go to Step 6 
  1. Turn OFF the ignition.
  2. Disconnect the multi-way harness connector of the fuel injectors.
  3. Probe the ignition 1 voltage circuit of the fuel injector, fuse side, with a test lamp connected to B+.
Does the test lamp illuminate?
- Go to Step 9  Go to Step 5 
Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
- Go to Step 13  Go to Step 8 
  1. Turn OFF the ignition.
  2. Disconnect the multi-way harness connector of the fuel injectors.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 1 voltage circuit of the fuel injector, fuse side, with a test lamp connected to a good ground.
Does the test lamp illuminate?
- Go to Step 7  Go to Step 10 
Test for continuity between the ignition 1 voltage circuit terminal and a fuel injector terminal, at the multi-way harness connector, fuel injector side. Refer to Testing for Continuity in Wiring Systems.
Does the DMM display a resistance above the specified value?
5 Ω Go to Step 11  Go to Step 12 
8 Test the ignition 1 voltage circuit of the fuel injector, between the multi-way harness connector and the fuel injectors for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
- Go to Step 14  Go to Diagnostic Aids
9 Repair the short to ground in the ignition 1 voltage circuit of the fuel injector. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?
- Go to Step 14  -
10 Repair the open in the ignition 1 voltage circuit between the UBEC and the multi-way connector. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?
- Go to Step 14  -
11 Repair the ignition 1 voltage circuit of the fuel injectors for an open/high resistance, between the multi-way connector and the splice. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?
- Go to Step 14  -
12 Repair the poor connection at the multi-way connector. Refer to Connector Repairs in Wiring Systems.
Did you complete the repair?
- Go to Step 14  -
13 Repair the short to a PCM ground in the ignition 1 voltage circuit of the fuel injector. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?
- Go to Step 14  -
14 Operate the system in order to verify the repair.
Did you correct the condition?
- System OK Go to Step 3