GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The manifold absolute pressure (MAP) sensor that resides in the engine intake manifold is integrated with the intake air temperature (IAT) sensor 2. The purpose of this integrated sensor is to measure the following:

    • The atmospheric pressure and the vacuum or the reduced pressure that exists under different operating conditions in the engine intake manifold
    • The supercharged air pressure that exists under high load or wide open throttle conditions in the engine intake manifold
    • The IAT sensor 2 after the supercharger and the intercooler as it enters the engine intake manifold
    • The IAT sensor 2 after the supercharger bypass valve and the intercooler as it enters the engine intake manifold

The MAP/IAT sensor 2 has the following types of circuits:

    • A powertrain control module (PCM) supplied and regulated MAP 5-volt reference circuit
    • A PCM supplied ground for the low reference circuit that is shared by the MAP and the IAT sensor 2
    • A MAP sensor signal circuit that supplies a voltage input to the PCM
    • A PCM supplied 5-volt, IAT signal circuit

The diaphragm within the MAP sensor responds to all of the various pressure changes in the intake manifold and provides a signal voltage to the PCM on the signal circuit relative to those pressure changes.

The PCM monitors the MAP sensor signal for voltage that is outside of the normal range of a properly operating sensor. If the PCM detects a MAP sensor signal that is not within range of 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 P0107, P0108, P0120, P0121, P0220, P0506, P0507, P2135 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 IAT is between -7 to +125°C (+19 to +257°F).
    • The change in throttle position (TP) is less than 5 percent.
    • The above enabling criteria must be stable for more than 5 seconds.
    • DTC P0106 runs continuously when the above conditions are met.

Conditions for Setting the DTC

    • The PCM detects that the MAP sensor signal is 25 kPa more than the calibrated estimate for more than 90 seconds.
        OR
    • The PCM detects that the MAP sensor signal is 45 kPa less than the calibrated estimate for more than 90 seconds.

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.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Inspect for the following conditions:

    • Any disconnected, damaged, or incorrectly routed vacuum hoses
    • Any damage or fractures to the manifold absolute pressure (MAP) sensor housing
    • A missing or damaged MAP sensor seal
    • Restrictions or debris in the MAP sensor vacuum port
    • An Intake manifold vacuum leak

Did you find and correct the condition?

--

Go to Step 22

Go to Step 3

3

Important: The following sensors share a bused low reference circuit within the powertrain control module (PCM) and a common ground. A high resistance on that shared portion will shift both sensors.

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the MAP Sensor parameter with a scan tool.
  3. Observe the BARO parameter with a scan tool.
  4. Compare the values.

Is the difference between the MAP Sensor parameter and the BARO parameter more than the specified value?

5 kPa

Go to Step 10

Go to Step 4

4

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. Accurately determine the altitude for your location.
  2. Observe the MAP Sensor kPa parameter with a scan tool.
  3. The MAP Sensor parameter should be within the specified pressure range for your altitude. Refer to Altitude Versus Barometric Pressure .

Is the MAP Sensor parameter within the specified range as indicated on the Altitude vs. Barometric Pressure table?

--

Go to Step 5

Go to Step 10

5

  1. Observe the MAP Sensor kPa parameter with a scan tool.
  2. Start the engine.

Does the MAP Sensor kPa parameter decrease?

--

Go to Step 6

Go to Step 10

6

  1. Turn OFF the ignition.
  2. Remove the MAP sensor from the engine intake manifold. Leave the MAP sensor connected to the engine harness.
  3. Connect a vacuum pump to the MAP sensor.
  4. Turn ON the ignition, with the engine OFF.
  5. Observe the MAP Sensor parameter with a scan tool.
  6. Apply vacuum to the MAP sensor in 1 inch Hg increments until 15 inches Hg is reached. Each 1 inch Hg should decrease the MAP Sensor parameter by 3-4 kPa.

Is the decrease in the MAP Sensor parameter consistent?

--

Go to Step 7

Go to Step 10

7

Apply vacuum with the vacuum pump until 20 inches Hg is reached.

Is the MAP Sensor parameter less than the specified value?

34 kPa

Go to Step 8

Go to Step 10

8

Disconnect the vacuum pump from the MAP sensor.

Does the MAP Sensor parameter return to the value observed in Step 4?

--

Go to Step 9

Go to Step 20

9

An engine in poor mechanical condition can cause this DTC to set. Inspect for the following conditions:

    • A restricted exhaust system--Refer to Restricted Exhaust .
    • Worn piston rings or valves--Refer to Engine Compression Test .
    • Incorrect cam timing--Refer to Camshaft Timing Chain, Sprocket, and Tensioner Replacement .

Did you find and correct the condition?

--

Go to Step 22

Go to Testing for Intermittent Conditions and Poor Connections

10

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 22

Go to Step 11

11

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

Is the MAP Sensor parameter less than the specified value?

0.1 V

Go to Step 12

Go to Step 15

12

  1. Turn ON the ignition, with the engine OFF.
  2. Connect a test lamp between the 5-volt reference circuit of the MAP sensor at the harness connector and a good ground.
  3. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM.

Is the voltage within the specified range?

4.8-5.2 V

Go to Step 14

Go to Step 13

13

Is the voltage more than the specified value?

5.2 V

Go to Step 16

Go to Step 17

14

Important: All electrical components and accessories must be turned OFF.

  1. Turn OFF the ignition for 90 seconds to allow the control modules to power down.
  2. Measure the resistance from the low reference circuit of the MAP sensor to a good ground with a DMM.

Is the resistance more than the specified value?

5 ohms

Go to Step 18

Go to Step 20

15

Test the MAP sensor signal circuit between the 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 22

Go to Step 19

16

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 22

Go to Step 19

17

Test the 5-volt reference circuit between the PCM and the MAP sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

18

Test the low reference circuit between the PCM and the MAP sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

19

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 22

Go to Step 21

20

Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 22

--

21

Replace the PCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 22

--

22

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 90 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 23

23

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