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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2006 🢒 Vibe - FWD 🢒 Restraints 🢒 SIR 🢒 DTC P2645

Circuit Description

The DTC P2645 Rocker Arm Actuator Solenoid Control Circuit diagnostic monitors the electrical circuit of the rocker arm oil control solenoid. The rocker arm oil control solenoid enables the powertrain control module (PCM) to operate the high speed cam system. The high speed cam system significantly increases valve lift at engine speeds above 6,000 RPM. A second camshaft lobe with a high lift profile is cast into each camshaft, alongside the low/medium speed lobes. Unique rocker arms follow both the high speed and low/medium speed cam lobes. At engine speeds below 6,000 RPM, the low/medium speed cam lobes operate the rocker arms. When the rocker arm oil control solenoid is turned ON between 6,000-8,200 RPM, the rocker arms are operated by the high speed cam lobes. The rocker arm oil control solenoid is controlled by a pulse width modulated (PWM) signal from the PCM. A fault in the solenoid control circuit will set a DTC P2645. For additional information on the operation of the rocker arm oil control system, refer to Rocker Arm Oil Control System Description .

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2645 Rocker Arm Actuator Solenoid Control Circuit

Conditions for Running the DTC
    • DTCs P0100, P0101, P0102, P0103, P0115, P0117, P0118, P0125, P0335, P0340, P0341, P0385 are not set.
    • The battery voltage is at least 11 volts.
    • The ignition is ON.
    • DTC P2645 runs continuously once the above condition is met.

Conditions for Setting the DTC

The PCM detects an open or a short in the control circuit of the rocker arm oil control solenoid.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL).
    • The PCM stores the conditions that were present when the DTC set as Freeze Frame data.

Conditions for Clearing the MIL/DTC
    • The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
    • A DTC clears after 40 consecutive warm-up cycles have occurred without a fault.
    • A DTC can be cleared by using the scan tool Clear DTC Information function.

Test Description

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

  1. The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool, if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

    2.

  2. This step checks the operation of the rocker arm oil control solenoid. This inspection is to be performed when the vehicle is at normal operating temperature with the engine speed at 1,500-2,500 RPM. Turning ON the rocker arm oil control solenoid will increase valve lift enough to cause a significant drop in engine speed.

    3.

  3. This step checks for electrical resistance in the wiring and connections of the rocker arm oil control solenoid circuit. Circuit resistance as small as 45 ohms can cause a DTC P2645 to set.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  1. Perform the scan tool Clear DTC Information function.
  2. Start the engine.
  3. Operate the engine for 1 minute.
  4. Review the scan tool data and check for DTC P2645.

Is DTC P2645 set?

Go to Step 4

Go to Step 3

3
  1. Start the engine.
  2. Allow the engine to reach normal operating temperature.
  3. With the transmission in Neutral, increase the engine speed to 1,500-2,500 RPM.
  4. Command the rocker arm oil control solenoid ON with the scan tool. Refer to Scan Tool Output Controls .

Does the engine idle very rough or stall when the rocker arm oil control solenoid is commanded ON?

Go to Intermittent Conditions

Go to Step 4

4

  1. Start the engine.
  2. Ensure that the engine has reached operating temperature.
  3. Turn OFF the engine.
  4. Disconnect the electrical connector to the rocker arm oil control solenoid valve.
  5. Start the engine.
  6. With the transmission in Neutral, increase the engine speed to 1,500-2,500 RPM.
  7. Connect the rocker arm oil control solenoid to B+ and ground with a pair of fused jumper wires.

Does the engine idle very rough or stall when the rocker arm oil control solenoid is connected to B+?

Go to Step 5

Go to Step 8

5
  1. Turn ON the ignition, with the engine OFF.
  2. Connect a test lamp to B+ and the Solenoid Low Control circuit of the rocker arm oil control solenoid.

Does the test lamp illuminate?

Go to Step 6

Go to Step 7

6
  1. Inspect the Rocker Arm Solenoid High Control circuit of the Rocker Arm Oil Control Solenoid for an open or a short.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 11

Go to Step 9

7
  1. Inspect the Rocker Arm Solenoid Low Control circuit of the Rocker Arm Oil Control Solenoid for an open.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 11

Go to Step 9

8

Replace the rocker arm oil control solenoid. Refer to Rocker Arm Oil Control Solenoid Valve Replacement .

Is the action complete?

Go to Step 11

--

9

  1. Inspect the electrical circuits and connections of the rocker arm oil control solenoid for high electrical resistance.
  2. Inspect for poor connections at the harness connectors of the powertrain control module (PCM) and the rocker arm oil control solenoid.
  3. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

Go to Step 11

Go to Step 10

10

Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Is the action complete?

Go to Step 11

--

11
  1. Use the scan tool in order to clear the DTCs.
  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 12

Go to Step 2

12

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 - Vehicle in Vehicle DTC Information

System OK