For 1990-2009 cars

### Circuit Description

The manifold absolute pressure (MAP) sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference circuit, and a signal circuit. The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit, and provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the signal circuit which is relative to the pressure changes in the manifold. With low MAP such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP such as ignition ON, with the engine OFF or WOT, the PCM should detect a high MAP sensor signal voltage. Certain vehicle models will also use the MAP sensor in order to calculate the barometric pressure (BARO) when the ignition is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is intermittently high, DTC P1106 will set.

### Conditions for Running the DTC

• | DTCs P0121, P0122, or P0123 are not set.

• | The engine has been running for a period of time that is determined by the startup coolant temperature. The time ranges from 2 minutes at less than -30°C (-22°F) to 1 second at more than -30 (86°F).

• | The throttle angle is less than 2 percent when the engine speed is less than 3,000 RPM.

| OR

• | The throttle angle is less than 30 percent when the engine speed is more than 3,000 RPM.

### Conditions for Setting the DTC

The MAP sensor voltage is intermittently more than 4.2 volts.

### 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

• | Inspect the MAP sensor vacuum source for leaks, for restrictions, or for poor connections.

• | If an intermittent condition exists, refer to Intermittent Conditions .

### Test Description

The number below refers to the step number on the diagnostic table.

1. Many intermittent open or shorted circuits occur with harness/connector movement caused by vibration, by engine torque, and by bumps. This step attempts to recreate this condition.

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. Install a scan tool.
2. Start the engine.
3. Monitor the diagnostic trouble code (DTC) information using the scan tool.

Does the scan tool display DTC P1635 or P0108 set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3 | Does the scan tool indicate that the MAP sensor voltage is more than the specified value? | 4.2 V | Go to Step 5 | Go to Step 4
4 | With a scan tool, observe the MAP sensor voltage, while moving the following components:

• | The MAP sensor connector

• | The wiring harness related to the MAP sensor

• | The PCM connector

Does the scan tool indicate that the MAP sensor voltage is more than the specified value and holding?

4.2 V

Go to Step 5

Go to Step 11

5 |

1. Turn OFF the ignition.
2. Disconnect the MAP sensor electrical connector.
3. Turn ON the ignition, with the engine OFF.

Does the scan tool indicate that the MAP sensor voltage is less than the specified value?

0.1 V

Go to Step 6

Go to Step 7

6 |

1. Disconnect the electrical connector of the engine coolant temperature (ECT) sensor. Refer to Engine Coolant Temperature Sensor Replacement .
2. Connect a test lamp to B+.
3. Probe the low reference circuit of the MAP sensor with the test lamp.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 8

7 | Test the signal circuit of the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10
8 | Test the low reference circuit of the MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10
9 | Inspect for poor connections at the MAP sensor. 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 11 | Go to Diagnostic Aids
10 | Inspect for poor connections at the PCM. 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 11 | Go to Diagnostic Aids
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 | System OK