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Makes 🢒 GMC_Truck 🢒 2005 🢒 TopKick C-Series (Conventional) C6/C7/C8 🢒 Engine 🢒 Engine Controls - 7.8L 🢒 DTC P2012

Circuit Description

The fuel 2 injector drive circuit is a high voltage supply and drives injectors installed to cylinders 4, 5, and 6. The engine control module (ECM) steps up the battery voltage and supplies the resulted high voltage to the related injectors continuity. If the fuel 2 injector drive circuit supply to cylinders 4, 5, or 6 is an open circuit, this DTC will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2012 Injector Positive Voltage Control Circuit Group 2 Open

Conditions for Running the DTC
    • The ignition switch is ON.
    • The battery voltage is between 10-16 volts.
    • The engine is running.
    • The crankshaft position (CKP) sensor is not failed.

Conditions for Setting the DTC

The ECM detects that the common 2 injector power supply circuit is an open circuit.

Action Taken When the DTC Sets
    • The ECM illuminates the malfunction indicator lamp (MIL) and reduced engine power indicator lamp, if fitted, when the diagnostic runs and fails.
    • The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.
    • The ECM disables cylinders 4, 5, and 6 injector operation.
    • The ECM limits fuel injection quantity for fail-safe operation.
    • The ECM closes the exhaust gas recirculation (EGR) valve and holds the EGR control.
    • The ECM inhibits cruise control.

Conditions for Clearing the DTC
    • The MIL resets when the ignition is turned OFF.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • Clear the MIL and the DTC with a scan tool.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Observe the 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. 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 3

Go to Intermittent Conditions

3

Is DTC P0204, P0205, or P0206 also set?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect the injector harness in-line connector from the cylinder head cover case.
  3. Measure the resistance through the intermediate connector between the injector power supply circuits and the injector control circuits 4, 5, and 6.

Are all of the resistance measures less than specified value?

1 ohms

Go to Step 5

Go to Step 7

5
  1. Test the injector power circuits between the engine control module (ECM) and the in-line connector for the following conditions:
    2. • An open circuit
    • High resistance
  2. Repair the circuits, as necessary.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 6

6
  1. Remove the cylinder head cover.
  2. Inspect the upper portion of the appropriate injector and the injector harness.
  3. Repair the condition, as necessary. Refer to Cylinder Head Replacement .

Did you find and correct the condition?

--

Go to Step 11

Go to Step 8

7
  1. Test the injector power supply circuits between the injector terminals and the intermediate connector for the following conditions:
    2. • An open circuit
    • High resistance
  2. Repair the circuits, as necessary.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

8
  1. Turn OFF the ignition.
  2. Inspect for connections at the intermediate connector.
  3. Repair the connections, as necessary.

Did you find and correct the condition?

--

Go to Step 11

Go to Intermittent Conditions

9
  1. Turn OFF the ignition.
  2. Disconnect the ECM.
  3. Inspect for poor connections at the harness connector of the ECM.
  4. Repair the connections, as necessary.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 10

10

Important: The new ECM must be programmed.

Replace the ECM. Refer to Engine Control Module Programming and Setup in Programming and Setup, Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming .

Did you complete the replacement?

--

Go to Step 11

--

11
  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 12

12

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK