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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Epica 🢒 Engine 🢒 Engine Controls - 2.5L (LBK) 🢒 DTC P0661

Circuit Description

An ignition 1 voltage is supplied to the intake manifold tuning (IMT) valve solenoid through a main relay and a fuse when the ignition key is turned ON. The control module controls the IMT solenoid by grounding the control circuit via an internal driver switch. The primary function of the driver is to supply ground for the controlled component. The control module monitors the status of the driver. If the engine control module (ECM) detects an incorrect voltage for the commanded state of the driver, this DTC sets.

DTC Descriptors

This diagnostic procedure supports the following DTC:

DTC P0661 Intake Manifold Tuning (IMT) Valve Solenoid Control Circuit Low Voltage

Conditions for Running the DTC
    • The ignition is ON.
    • DTC P0661 runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for more than 25 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.

Test Description

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

  1. A click should be heard or felt when the valve operates. Ensure that both the ON and the OFF states are commanded. Repeat the commands as necessary.

    2.

  2. This step tests if the IMT solenoid ignition 1 voltage circuit has a fault. A fault in the main relay, fuse, or underhood bussed electrical center (UBEC) can cause multiply DTC's to set and a no start condition.

    3.

  3. This step verifies that the ECM is providing ground to the IMT solenoid.

    4.

  4. This step tests if the IMT solenoid control circuit is grounded.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Engine Control Module 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. Turn ON the ignition, with the engine OFF.
  2. With the scan tool, command the IMT solenoid ON and OFF.

Do you hear or feel a click from the IMT solenoid when the valve is commanded ON and OFF?

Go to Step 3

Go to Step 4

3
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. 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 Intermittent Conditions

4

  1. Disconnect the IMT solenoid electrical connector.
  2. Probe the ignition 1 voltage circuit of the IMT solenoid with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 11

5

  1. Connect a test lamp between the control circuit of the IMT solenoid and the ignition 1 voltage circuit of the IMT solenoid.
  2. With a scan tool, command the IMT solenoid ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 9

Go to Step 6

6

Does the test lamp remain illuminated with each command?

Go to Step 8

Go to Step 7

7

Test the control circuit of the IMT solenoid for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 10

8

Test the control circuit of the IMT solenoid for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 10

9

Test for an intermittent and for a poor connection at the IMT solenoid . 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 14

Go to Step 12

10

Test for an intermittent and for a poor connection at 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 14

Go to Step 13

11
  1. Repair the ignition 1 voltage circuit of the IMT solenoid for one of the following conditions:
    2. • An open
    • A short to ground
    • High resistance
  2. Replace the fuse as necessary. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

12

Replace the IMT solenoid. Refer to Intake Manifold Tuning Valve Actuator Solenoid Replacement

Did you complete the replacement?

Go to Step 14

--

13

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 14

--

14
  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 15

15

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