GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 CTS - RHD 🢒 Engine 🢒 Engine Controls - 2.6L and 3.2L 🢒 DTC P0261, P0264, P0267, P0270, P0273, or P0276

Circuit Description

The engine control module (ECM) enables the appropriate fuel injector on the intake stroke 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. The ECM monitors the status of each driver. If the ECM detects a short to ground for the commanded state of the driver, a fuel injector control DTC sets.

Conditions for Running the DTC
    • The engine speed is more than 40 RPM.
    • The system voltage is between 8-18 volts.

Conditions for Setting the DTC
    • The ECM detects low voltage condition on the fuel injector control circuit.
    • The condition exists for 30 seconds.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
    • Performing the Fuel Injector Coil Test may help isolate an intermittent condition. Refer to Fuel Injector Solenoid Coil Test .
    • If the condition is intermittent, refer to Intermittent Conditions .

Test Description

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

  1. This step verifies that the condition is present.

    2.

  2. This step isolates the condition. If the test lamp is illuminated the fuel injector control circuit is shorted to ground between the multi-way connector and the ECM.

    3.

  3. This step tests for a short to ground in the fuel injector control circuit between the multi-way connector and the affected fuel injector.

    4.

  4. This step isolates the circuit between the multi-way connector and the ECM.

  5. This step inspects for fuel injector harness damage between the multi-way connector and the intake plenum. Careful inspection may isolate the condition before removal of the intake plenum.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls 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

Important: If DTCs P0261, P0264, P0267, P0270, P0273 and P0276 are all set, inspect ignition 1 voltage supply circuit for a short to ground.

  1. Clear the DTCs with a scan tool.
  2. Attempt to start the engine.

Does a fuel injector DTC set?

Go to Step 4

Go to Step 3

3

  1. Observe the Freeze Frame/Failure records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Attempt to start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did 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 affected fuel injector control circuit, engine control module (ECM) side, with a test lamp connected to B+.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 6

Go to Step 5

5

With the test lamp still connected to B+, probe the affected fuel injector control circuit, fuel injector harness side.

Does the test lamp illuminate?

Go to Step 7

Go to Intermittent Conditions

6

Test the control circuit of the affected fuel injector for a short to ground between the multi-way connector and the ECM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 10

7

  1. Inspect the accessible fuel injector jumper harness between the multi-way connector and the intake plenum for the following:
    2. • Damaged or pinched wiring
    • Broken wires inside the insulation
  2. Repair as necessary. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 8

8
  1. Remove the upper intake. Refer to Intake Plenum Replacement in Engine Mechanical.
  2. Test the control circuit of the fuel injector for a short to ground between the multi-way connector and the affected fuel injector connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

9

Test for an intermittent and for a poor connections at the harness connector of the appropriate 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 13

Go to Step 11

10

Test for an intermittent and for a poor connections at the harness connector of the ECM. 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 13

Go to Step 12

11

Replace the affected fuel injector. Refer to Fuel Injector and Fuel Rail Replacement .

Did you complete the replacement?

Go to Step 13

--

12

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 13

--

13
  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. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 14

14

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK