For 1990-2009 cars
Engine Controls Components
Engine Data Sensors
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The Powertrain Control Module (PCM) uses the manifold absolute pressure (MAP) sensor to control the fuel delivery and the ignition timing. The MAP sensor measures the changes in the intake manifold pressure which result from the engine load (intake manifold vacuum) and the RPM changes and converts the measurements into a voltage output. The PCM sends a 5 volt reference voltage to the MAP sensor. As the manifold pressure changes, the output voltage of the MAP sensor also changes. By monitoring the MAP sensor output voltage, the PCM determines the manifold pressure. A lower pressure (low voltage) output voltage will be about 1.0 to 1.5 volts at idle. A higher pressure (high voltage) output voltage will be about 4.5 to 4.8 volts at wide open throttle (WOT). The MAP sensor is also used under certain conditions to measure the barometric pressure, allowing the PCM to make adjustments for different altitudes.

### Conditions for Running the DTC

• | A DTC P0122 or a DTC P0123 is not set.

• | The engine speed is less than 1000 RPM.

| OR

• | The engine speed is more than 1000 RPM and the throttle position (TP) is more than 15 percent.

### Conditions for Setting the DTC

• | The MAP is less than 11.8 kPa.

• | The above conditions are met for at least 6.25 seconds.

### Action Taken When the DTC Sets

• | The Malfunction Indicator Lamp (MIL) will illuminate after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.

• | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.

• | A history DTC is stored.

• | The coolant fan turns on.

• | The PCM will substitute a fixed MAP value and use the throttle position to control the fuel delivery. The scan tool will not show the defaulted value.

• | The vehicle will operate in Open Loop when the vehicle speed is under 8 km/h (5 mph). The vehicle will operate in Closed Loop when the vehicle speed is over 8 km/h (5 mph).

### Conditions for Clearing the MIL/DTC

• | The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs without a fault.

• | A history DTC will clear after 40 consecutive warm up cycles without a fault.

• | Use a scan tool to clear the DTCs.

### Diagnostic Aids

Important: After repairs use the scan tool Fuel Trim Reset function to reset the long term fuel trim to 128 (0 percent).

With the ignition switch on and the engine off, the manifold pressure is equal to the atmospheric pressure and the signal voltage will be high. This information is used by the PCM as an indication of vehicle altitude. Comparison of this reading with a known good vehicle with the same sensor is a good way to check the accuracy of a suspect sensor. Readings should be the same within 0.4 volt.

If a DTC P0107 is intermittent, refer to Symptoms or Manifold Absolute Pressure Sensor Output Diagnosis for further diagnosis.

### Test Description

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

1. This step determines if DTC P0107 is the result of a hard malfunction or an intermittent condition.

2. Connecting a jumper wire between the connector terminals B and C (signal circuit to the 5.0 volts circuit) will determine if the MAP sensor is malfunctioning or if there is a problem with the PCM or the wiring.

3. The scan tool may not display 5.0 volts. The important thing is that the PCM recognizes the voltage as more than 4.0 volts, indicating that the PCM and the MAP sensor signal circuit are OK. A test lamp that illuminates indicates a short to ground in the signal circuit.

4. Important: The PCM uses a single internal 5.0 volt power supply to supply power to all of the engine control components. If one component shorts a 5.0 volt reference circuit to ground or battery voltage, the other 5.0 volt reference circuits will also have a low or high voltage.

   An open or a short to ground in the 5.0 volt reference circuit could also set additional DTCs.

5. The MAP sensor vacuum source should be thoroughly checked for restrictions. A drill bit can be used to clean out any casting flash that may exist in the manifold vacuum port.

6. The replacement PCM must be reprogrammed and the Crankshaft Position System Variation Learn procedure must be preformed.

#### DTC P0107 Manifold Absolute Pressure (MAP) Circuit - Low Voltage

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Connect a scan tool.
2. Start and idle the engine.
3. Monitor the manifold absolute pressure (MAP) sensor voltage on the scan tool.

Is the MAP voltage less than the specified value?

0.25 V

Go to Step 3

Go to Step 4

3 |

1. Turn off the ignition.
2. Disconnect the MAP sensor connector.
3. Connect a fused jumper wire between the MAP signal circuit terminal and the 5.0 volt reference circuit terminal.
4. Turn on the ignition, leaving the engine off.

Is the voltage more than the specified value?

4.7 V

Go to Step 5

Go to Step 6

4 |

1. Turn on the ignition, leaving the engine off.
2. Review and record the Freeze Frame data.
3. Start the engine.
4. Operate the vehicle within the Freeze Frame conditions and the Conditions for Running the DTC, as specified in the supporting text.

Is the voltage less than the specified value?

0.25 V

Go to Step 3

Go to Diagnostic Aids

5 |

1. Turn off the ignition.
2. Inspect the MAP sensor connector for the following conditions:

• | A poor terminal connection

• | The correct terminal tension

• | A poor terminal-to-wire connection

Did you find a problem?

--

Go to Step 8

Go to Step 11

6 |

1. Turn off the ignition.
2. Remove the fused jumper.
3. Connect a test lamp to B+.
4. Probe the signal circuit terminal of the MAP sensor .
5. Turn the ignition on, leaving the engine off.

Is the voltage more than the specified value?

4.0 V

Go to Step 7

Go to Step 13

7 | Important:: The PCM uses a single internal 5.0 volt power supply to supply power to all the engine control components. If one component shorts the 5.0 volt reference circuit to ground or battery voltage, the other 5.0 volt reference circuits will also have a low or high voltage.

1. Turn off the ignition.
2. Test the 5.0 volt reference circuit of the MAP sensor for the following conditions:

• | An open circuit

• | A short to ground

Did you find a problem?

--

Go to Step 10

Go to Step 12

8 | Repair the connection as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 15 | --
9 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the repair? | -- | Go to Step 15 | --
10 | Repair the 5.0 volt reference circuit of the MAP sensor. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 15 | --
11 |

1. Remove the MAP sensor hose from the manifold port.
2. Inspect the vacuum port hose and the MAP sensor for the following conditions:

• | A plugged MAP sensor nipple

• | A plugged intake manifold port to the MAP sensor

• | A plugged vacuum source

3. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 9

12 |

1. Inspect for a poor connection at the PCM.

Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

2. Replace the PCM. Powertrain Control Module Replacement .

Did you complete the repair?

--

Go to Step 15

--

13 |

1. Turn off the ignition.
2. Test the MAP sensor signal circuit for the following conditions:

• | An open circuit

• | A short to ground

• | A short to the sensor ground

Did you find a problem?

--

Go to Step 14

Go to Step 12

14 | Repair the MAP sensor signal circuit. Refer to Wiring Repairs In Wiring Systems. Did you complete the repair? | -- | Go to Step 15 | --
15 |

1. Use a scan tool to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK