For 1990-2009 cars

### Circuit Description

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature, and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The powertrain control module (PCM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The PCM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the PCM, relative to the pressure changes on the MAP sensor signal circuit. The PCM converts the signal voltage input to a pressure value.

Under normal operation, the highest pressure that can exist in the intake manifold is equal to the BARO. This occurs when the vehicle is operated at wide-open throttle (WOT), or when the ignition is ON while the engine is OFF. Under these conditions, the PCM uses the MAP sensor to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. The MAP can range from 10 kPa when pressures are low to as much as 104 kPa when pressures are high, depending on the BARO.

Within the PCM, the intake flow rationality diagnostic has the ability to determine an inaccurate input from the three systems it monitors. Calibrated within the diagnostic are estimates for the MAP, the mass air flow (MAF), and the throttle position (TP) for all engine operating conditions. The diagnostic compares the estimated values to the actual sensor inputs. If the PCM detects that the MAP sensor input is not within a calibrated limit of the estimated value, DTC P0106 sets.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0106 Manifold Absolute Pressure (MAP) Sensor Performance

### Conditions for Running the DTC

• | DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0335, P0336 are not set.

• | The engine speed is between 400-6,400 RPM.

• | The engine coolant temperature (ECT) is between 70-125°C (158-257°F).

• | The intake air temperature (IAT) is between -7 to +125°C (+19 to +257°F).

• | DTC P0106 runs continuously when the above conditions are met.

### Conditions for Setting the DTC

The PCM detects that the MAP sensor pressure is not within the calibrated limit of the estimated value for more than 1 second.

### Action Taken When the DTC Sets

• | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

• | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

### Conditions for Clearing the MIL/DTC

• | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

• | 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 emission related diagnostic.

• | Clear the MIL and the DTC with a scan tool.

### Test Description

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

1. This step tests the ability of the MAP sensor to correctly indicate BARO.

2. The measurement noted in this step will be used in subsequent steps if the measurement does not exceed the specified value.

3. This step calculates the resistance in the 5-volt reference circuit.

4. This step calculates the resistance in the low reference circuit.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn ON the ignition, with the engine OFF.
2. Monitor the DTC information with the scan tool.

Is DTC P0651 also set?

--

Go to DTC P0651

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Inspect for the following conditions:

• | Disconnected, damaged, or incorrectly routed vacuum hoses

• | Missing or damaged manifold absolute pressure (MAP) sensor seal

• | Restrictions in the MAP sensor vacuum source

• | Intake manifold vacuum leaks

Did you find and correct the condition?

--

Go to Step 26

Go to Step 4

4 | Important: The vehicle used for the comparison is not limited to the same type of vehicle as is being serviced. A vehicle known to provide an accurate reading is acceptable. Do you have access to another vehicle in which the MAP sensor pressure can be observed with a scan tool? | -- | Go to Step 5 | Go to Step 6
5 |

1. In both vehicles, turn ON the ignition, with the engine OFF.
2. Observe the MAP sensor pressure with a scan tool.
3. Observe the MAP sensor pressure in the known good vehicle with a scan tool.
4. Compare the values.

Is the difference between the values less than the specified value?

3 kPa

Go to Step 7

Go to Step 12

6 | Important: The Altitude vs. Barometric Pressure table indicates a pressure range for a given altitude under normal weather conditions. Weather conditions consisting of very low or very high pressure and/or very low or very high temperature may cause a reading to be slightly out of range.

1. Turn ON the ignition, with the engine OFF.
2. Observe the MAP sensor pressure with a scan tool.
3. The MAP sensor pressure should be within the range specified for your altitude. Refer to Altitude Versus Barometric Pressure .

Does the MAP sensor indicate the correct barometric pressure?

--

Go to Step 7

Go to Step 12

7 |

1. Observe the MAP sensor pressure with a scan tool.
2. Start the engine.

Does the MAP sensor pressure change?

--

Go to Step 8

Go to Step 12

8 |

1. Turn OFF the ignition.
2. Remove the MAP sensor from the engine vacuum source. Leave the MAP sensor connected to the engine harness.
3. Connect a J 23738-A Mityvac to the MAP sensor.
4. Turn ON the ignition, with the engine OFF.
5. Observe the MAP sensor pressure with the scan tool.
6. Apply vacuum to the MAP sensor with the J 23738-A in 1 inch Hg increments until 15 inches Hg is reached. Each 1 inch Hg should decrease MAP sensor pressure by 3-4 kPa on the scan tool.

Is the decrease in MAP sensor pressure consistent?

--

Go to Step 9

Go to Step 12

9 | Apply vacuum with the J 23738-A until 20 inches Hg is reached. Is the MAP sensor pressure less than the specified value? | 34 kPa | Go to Step 10 | Go to Step 12
10 | Disconnect the J 23738-A from the MAP sensor. Does the MAP sensor pressure return to the value observed in step 4 or 5? | -- | Go to Step 11 | Go to Step 24
11 | Inspect for the following conditions:

• | Incorrect cam timing--Refer to Timing Chain Alignment Diagram for the correct timing.

• | Restricted exhaust flow--Refer to Restricted Exhaust .

• | Worn piston rings--Refer to Engine Compression Test .

Did you find and correct the condition?

--

Go to Step 26

Go to Testing for Intermittent Conditions and Poor Connections

12 | Test for an intermittent and for a poor connection at the MAP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 13
13 |

1. Disconnect the MAP sensor electrical connector.
2. Observe the MAP sensor parameter with the scan tool.

Is the pressure less than the specified value?

12 kPa

Go to Step 14

Go to Step 18

14 | Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Refer to Circuit Testing . Note the measurement as "Supply voltage". Is the voltage more than the specified value? | 5.2 V | Go to Step 19 | Go to Step 15
15 |

1. Connect a test lamp and a DMM in series between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector.
2. Measure the amperage with the DMM. Note the measurement as "Amperage".

Is the amperage equal to the specified value?

0 mA

Go to Step 21

Go to Step 16

16 |

1. Remove the DMM from the circuit.
2. Connect the test lamp between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector.
3. Measure the voltage from the 5-volt reference circuit at the test lamp to a good ground with the DMM. Note the measurement as "Load voltage drop".

Important: Before any calculations are performed, ensure that all measurements are converted into like units, for example volts/amps or millivolts/milliamps.

4. Subtract the "Load voltage drop" from the "Supply voltage". Note the result as "Supply voltage drop".
5. Divide the "Supply voltage drop" by the "Amperage".

Is the result more than the specified value?

5 ohms

Go to Step 20

Go to Step 17

17 |

1. Measure the voltage from the low reference circuit of the MAP sensor at the test lamp to a good ground with the DMM. Note the result as "Low reference voltage drop".

Important: Before any calculations are performed, ensure that all measurements are converted into like units, for example volts/amps or millivolts/milliamps.

2. Divide the "Low reference voltage drop" by the "Amperage".

Is the result more than the specified value?

5 ohms

Go to Step 22

Go to Step 24

18 | Test the MAP sensor signal circuit between the powertrain control module (PCM) and the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 23
19 | Test all branches of the 5-volt reference circuit that is shared with the MAP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 23
20 | Test the 5-volt reference circuit between the PCM and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 23
21 | Test the low reference circuit between the PCM and the MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 23
22 | Test the low reference circuit between the PCM and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 23
23 | Test for shorted terminals and for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 25
24 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 26 | --
25 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 26 | --
26 |

1. Clear the DTCs with the scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the Conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

--

Go to Step 2

Go to Step 27

27 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK