LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Buick >> 2004 >> Century Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (DTC P0140 To P0496) >> Engine Controls Diagnosis >> DTC P0201-P0206 >> Test Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Description

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

  1. 4:  This step isolates the condition. If the test lamp blinks, the PCM is providing ground to the fuel injector.
  2. 5:  This step tests if a ground is constantly being applied to the fuel injector.
  3. 6:  This step isolates the circuit between the multi-way connector and the PCM. An open or short to voltage on the fuel injector control circuit will not allow the test lamp to blink.
  4. 8:  This step inspects for fuel injector harness damage between the multi-way connector and the upper intake manifold. Careful inspection may isolate the condition before removal of the upper intake manifold.
  5. 13:  This step isolates the circuit between the multi-way connector and the fuel injector. A short to voltage on the fuel injector control circuit will set this DTC.
DTC P0201-P0206

Step Action Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  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
  1. Clear the DTCs with a scan tool.
  2. Idle the engine at the normal operating temperature.
  3. Monitor the misfire current counters with a scan tool.
Are any of the misfire current counters incrementing?		 Go to Step 4  Go to Step 3 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close as possible to the Freeze Frame/Failure Records that you observed.
Does the DTC fail this ignition?		 Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn OFF the ignition.
  2. Disconnect the fuel injector harness multi-way connector.
  3. Probe the appropriate fuel injector control circuit, at the powertrain control module (PCM) side, of the fuel injector harness multi-way connector with a test lamp connected to B+.
  4. Crank the engine.
Does the test lamp blink when cranking the engine?		 Go to Step 8  Go to Step 5 
5  Does the test lamp remain illuminated at all times? Go to Step 7  Go to Step 6 
6  Test the control circuit of the fuel injector for a short to voltage or an open between the multi-way connector and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 18  Go to Step 14 
7 Test the control circuit of the fuel injector for a short to ground between the multi-way connector and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 18  Go to Step 17 
8  Inspect the accessible fuel injector jumper harness between the multi-way connector and the plenum for the following conditions:
  • Poor connections at the multi-way connector
  • Damaged or pinched wiring
  • Broken wires inside the insulation

Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 18  Go to Step 9 
9
  1. Remove the upper intake manifold. Refer to Intake Manifold Replacement - Upper in Engine Mechanical.
  2. Probe the appropriate fuel injector control circuit, fuel injector side, at the multi-way connector, with a test lamp connected to B+.
Does the test lamp illuminate?		 Go to Step 15  Go to Step 10 
10 With a DMM, test for continuity between the ignition voltage terminal and the appropriate fuel injector control circuit terminal, at the multi-way connector. Refer to Testing for Continuity in Wiring Systems.
Does the DMM indicate OL?		 Go to Step 11  Go to Step 13 
11 Test the control circuit of the fuel injector for an open, or poor connections at the fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 18  Go to Step 12 
12 Test the ignition voltage circuit of the fuel injector for an open between the fuel injector and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 18  Go to Step 16 
13  Test the control circuit of the fuel injector for a short to voltage, or a short to another circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 18  Go to Step 16 
14 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 18  Go to Step 17 
15 Repair the short to ground in the fuel injector control circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 18  -
16 Replace the appropriate fuel injector. Refer to Fuel Injector Replacement .
Did you complete the replacement?		 Go to Step 18  -
17 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 Go to Step 18  -
18
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC run and pass?		 Go to Step 19  Go to Step 2 
19 With a scan tool, observe the stored information, Capture Info.
Does the scan tool display any DTCs that you have not diagnosed?		 Go to Diagnostic Trouble Code (DTC) List System OK
scientia non olet · About LEMON Manuals