For 1990-2009 cars

### Circuit Description

The intake plenum switchover solenoid is powered by switched battery voltage from the engine controls power relay. The solenoid is activated by a control circuit from the engine control module (ECM). The ECM controls the solenoid by grounding the control circuit with an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the ECM. When the ECM is commanding a component ON, the voltage of the control circuit should be low, near 0 volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near the battery voltage. If the fault detection circuit senses a voltage other than what is expected, a diagnostic trouble code (DTC) will set.

### Conditions for Running the DTC

• | The ignition voltage is 7.5-15 volts.

• | The engine speed is more than 40 RPM.

### Conditions for Setting the DTC

A short to ground, an open circuit, or a short to battery voltage is detected on the control circuit.

### Action Taken When the DTC Sets

• | The control module stores the DTC information into memory when the diagnostic runs and fails.

• | The malfunction indicator lamp (MIL) will not illuminate.

• | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.

• | The driver information center, if equipped, may display a message.

### Conditions for Clearing the DTC

• | 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 non-emission related diagnostic.

• | Clear the DTC with a scan tool.

### Diagnostic Aids

Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.

Check for the following conditions:

• | Poor connections at the ECM or at the component--Inspect the harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems for the proper procedure.

• | Damaged harness--Inspect the wiring harness for any damage. If the harness appears to be OK, observe the scan tool while moving the related connectors and the wiring harnesses. A change in the display may help in order to locate the fault.

Refer to Intermittent Conditions for the intermittents.

### Test Description

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

1. Listen for an audible click when the solenoid operates. Repeat the commands as necessary.

2. This test can detect a partially shorted coil which would cause an excessive current flow. Leaving the circuit energized for 2 minutes allows the coil to warm up. When the coil becomes warm the coil may open causing the amps to drop to 0, or short causing the amps to go above 0.75.

#### DTC P1112 Intake Plenum Switchover Solenoid Control Circuit

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Engine Controls Schematics
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. Command the solenoid ON and OFF with the scan tool.

Does the solenoid turn ON and OFF?

--

Go to Step 3

Go to Step 5

3 |

1. Turn OFF the ignition.
2. Disconnect the ECM.
3. Jumper the engine controls power relay control circuit to ground.
4. Use the DMM on a 10-amp scale in order to measure the current from the solenoid control circuit in the ECM harness connector to ground for 2 minutes.

Is the amperage within the specified range?

100-750 mA

Go to Diagnostic Aids

Go to Step 4

4 |

1. Turn OFF the ignition.
2. Disconnect the solenoid.
3. Measure the resistance from the solenoid control circuit in the ECM harness connector to ground with the DMM. The DMM should display an infinite resistance.

Does the DMM display an infinite resistance?

--

Go to Step 16

Go to Step 11

5 |

1. Turn OFF the ignition.
2. Disconnect the solenoid.
3. Turn ON the ignition, with the engine OFF.
4. Probe the Switched B+ circuit in the solenoid harness connector with the test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 13

6 |

1. Turn OFF the ignition.
2. Probe the control circuit of the solenoid with a test lamp connected to ground.
3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

--

Go to Step 12

Go to Step 7

7 |

1. Turn OFF the ignition.
2. Probe the control circuit of the solenoid with a test lamp connected to battery positive.
3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 8

8 |

1. Probe the control circuit of the solenoid with a test lamp connected to battery positive.
2. Command the solenoid ON and OFF with the scan tool.

Does the test lamp turn ON and OFF?

--

Go to Step 14

Go to Step 10

9 |

1. Turn OFF the ignition.
2. Disconnect the ECM connector C1.
3. Probe the control circuit of the solenoid with a test lamp connected to battery positive.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 15

10 |

1. Turn OFF the ignition.
2. Disconnect the ECM connector C1.
3. Test for an open or high resistance in the control circuit of the solenoid.
4. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 18

Go to Step 15

11 | Repair the short to ground in the control circuit of the solenoid. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 18 | --
12 | Repair the short to voltage in the control circuit of the solenoid. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 18 | --
13 | Repair the switched B+ circuit to the solenoid. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 18 | --
14 | Test for poor connections or poor terminal contact at the 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 18 | Go to Step 16
15 | Check for poor connections or poor terminal tension at the ECM harness connector. 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
16 | Replace the solenoid. Refer to Intake Plenum Switchover Solenoid Replacement . Did you complete the replacement? | -- | Go to Step 18 | --
17 | Important:

• | Perform the idle learn procedure when replacing the ECM or the throttle body.

• | This vehicle is equipped with a theft deterrent system which interfaces with the engine control module (ECM). Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle.

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the action?

--

Go to Step 18

--

18 |

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 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