For 1990-2009 cars
Engine Controls Components
Cell 21: Engine Data Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The manifold absolute pressure (MAP) sensor measures changes in the intake manifold pressure. The powertrain control module (PCM) provides a 5 volt reference voltage to the MAP sensor. The MAP sensor changes the reference voltage in response to changes in the engine load and changes in the engine speed. The PCM monitors the MAP sensor voltage. A low voltage reading at the PCM indicates low manifold pressure. A high voltage reading at the PCM indicates high manifold pressure.

### Conditions for Running the DTC

• | The engine speed is steady.

• | The throttle position is steady.

### Conditions for Setting the DTC

• | The MAP sensor value that is indicated while cranking differs from the MAP value by less than 1.3 kPa after the engine is started .

• | Barometric pressure differs from MAP sensor pressure by less than 33 kPa, for at least 2 minutes.

### Action Taken When the DTC Sets

• | The PCM illuminates the malfunction indicator lamp (MIL).

• | The PCM records the operating conditions at the time that the diagnostic fails. This information is stored in the Freeze Frame buffer.

### Conditions for Clearing the DTC

• | The MIL turns OFF after 3 consecutive trips during which the diagnostic runs, and a fault is not detected.

• | A History DTC clears after 40 consecutive warm-up cycles without a fault.

• | Use the Clear DTC Information function of the scan tool, or disconnect the PCM battery feed in order to clear the DTC.

### Diagnostic Aids

Check for any of the following conditions:

• | Check for a blocked vacuum passage and for a leaking vacuum passage to the MAP sensor.

• | Check the engine for vacuum leaks.

• | A shifted MAP sensor may cause DTC P0106 to set. Compare the MAP sensor voltage readings on a scan tool with the readings of a known good sensor.

• | A faulty electrical connection to the PCM.

• | Check for an exhaust restriction. A restriction in the catalytic converter can cause the MAP sensor output to be skewed. Refer to Restricted Exhaust System Check .

An intermittent malfunction may be caused by a fault in the MAP sensor electrical circuit. Inspect the wiring harness and the components for any of the following conditions:

• | Backed out terminals.

• | Incorrect mating of terminals.

• | Broken electrical connector locks.

• | Incorrectly formed terminals or damaged terminals.

• | Faulty terminal-to-wire connections.

• | Physical damage to the wiring harness.

• | A broken wire inside the insulation.

• | Corrosion of electrical connections, of splices, or of terminals.

If DTC P0106 cannot be duplicated, the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

Use the following MAP Conversion table in order to view the relationship between manifold pressure (vacuum), MAP sensor kPa and MAP sensor circuit voltage as displayed on the scan tool.

Manifold Pressure | MAP kPa Display | MAP Volts Display
--- | --- | ---
Sea Level | 99 | 4.75
5 in Hg | 82 | 3.93
10 in Hg | 64 | 3.07
15 in Hg | 48 | 2.30
20 in Hg | 30 | 1.44

### Test Description

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

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

2. Checks the MAP sensor reading on the scan tool .

3. This step determines if the fault is still present.

4. Check for freezing of water vapor in the vacuum line in cold weather conditions.

5. This step checks for the correct input circuit voltage to the MAP sensor . The MAP sensor voltage display on the scan tool will indicate 6.99 volts with the MAP sensor disconnected. This is caused by the scan tool software and should be considered normal. Ignore the scan tool voltage, and use the DMM for all voltage checks when diagnosing DTC P0106.

6. This step checks the ground circuit of the MAP sensor.

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. Turn ON the ignition, leaving the engine OFF.
2. Select the MAP sensor parameter on the scan tool.
3. Record the MAP sensor value.
4. Start the engine.
5. Record the MAP sensor value.

Did the scan tool MAP sensor reading change more than the specified value?

33 kPa

Go to Step 3

Go to Step 4

3 |

1. Turn ON the ignition, leaving the engine OFF.
2. Perform the Clear DTC Information function with the scan tool .
3. Operate the vehicle within the Freeze Frame conditions as specified.

Did a DTC P0106 set?

--

Go to Step 4

Go to Diagnostic Aids

4 |

1. Check for any of the following conditions:

• | Disconnected vacuum hoses, damaged vacuum hoses, or incorrectly installed vacuum hoses

• | Intake manifold vacuum leaks

• | A leaking MAP sensor seal

• | Vacuum leaks at the throttle body.

• | A faulty PCV valve or an incorrectly installed PCV valve

• | An air intake restriction

• | An exhaust restriction Refer to Restricted Exhaust System Check .

2. Repair as necessary.

Was a repair necessary?

--

Go to Step 11

Go to Step 5

5 |

1. Turn OFF the ignition.
2. Disconnect the electrical connector from the MAP sensor .
3. Turn on the ignition, leaving the engine off.
4. Measure the voltage from the harness side of the MAP sensor input circuit to ground with a DMM.

Is the voltage within the specified value?

4.9-5.0 V

Go to Step 6

Go to Step 7

6 | Measure the voltage from the MAP sensor signal circuit to the harness side of the MAP sensor ground circuit with the DMM. Is the voltage between the specified value? | 4.9-5.0 V | Go to Step 8 | Go to Step 9
7 |

1. Check the MAP sensor input circuit for any of the following conditions:

• | An open circuit

• | A short to ground

• | A short to B+

• | A MAP sensor input circuit that is shorted to the MAP sensor ground circuit

2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 11

Go to Step 10

8 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Is the action complete? | -- | Go to Step 11 | --
9 | Repair the open or the cause of electrical resistance in the MAP sensor ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 11 | --
10 | Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 11 | --
11 |

1. Perform the Clear DTC Information function with the scan tool, and road-test the vehicle within the Freeze Frame conditions.
2. Review the scan tool data, and inspect for any DTCs. The repair is complete if there are not stored DTCs.

Are any DTCs displayed on the scan tool?

--

Go to the applicable DTC table

System OK