GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The engine control module (ECM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The ECM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the ECM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The ECM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The ECM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the TP sensor is more than 28 percent. The MAP sensor contains the following circuits:

    • A 5-volt reference
    • A low reference
    • A MAP sensor signal

If the ECM detects the MAP sensor signal is not within the predicted range this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0106 Manifold Absolute Pressure (MAP) Sensor Performance

Condition for Running the DTC

    • The altitude compensated MAP reading is higher than high threshold or lower than low threshold table based on RPM and the TP signal.
    • DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0201, P0202, P0203, P0204, P0300, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0506, P0507, and P1404 are not set.
    • The engine is running.
    • Valid barometric pressure (BARO) update
    • The torque converter clutch (TCC) is at a steady state.
    • Air conditioning (A/C) steady state
    • The engine speed is between 1,300-4,500 RPM.
    • The change in engine speed is less than 200 RPM.
    • Change in the idle air control (IAC) is less than 5 percent.
    • The coolant temperature is greater than -10°C (+14°F).
    • The change in throttle position (TP) is less than 3 percent, or the change in MAP is less than 5 percent.
    • The change in the exhaust gas recirculation (EGR) value is less than 6 percent.
    • All of the above are stabilized for 1.5 seconds.
    • DTC P0106 runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the actual MAP signal is not within the predicted range for more than 25 seconds.

Action Taken When the DTC Sets

    • The malfunction indicator lamp (MIL) will illuminate after 3 consecutive ignition cycles with a fail.
    • The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame/Failure Records buffers.
    • A history DTC is stored.
    • The ECM will substitute a fixed MAP value and use the TP sensor to control the fuel delivery. The scan tool will not show defaulted value.

Conditions for Clearing the MIL/DTC

    • The MIL will turn OFF after 4 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.
    • DTCs can be cleared by using the scan tool.
    • Disconnect the ECM battery feed for more than 10 seconds.

Diagnostic Aids

With the ignition ON and the engine stopped, the manifold pressure is equal to atmospheric pressure and the signal voltage will be high. This information is used by the ECM 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 suspected sensor. Reading should be the same +0.4 volt.

The MAP sensor vacuum source should be thoroughly inspected for restrictions at the intake manifold.

Test Description

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

  1. While starting the engine, the MAP sensor should detect any changes in manifold pressure. This test is to determine if the sensor is stuck at a value.

  2. A normal MAP sensor will react as quickly to the throttle changes. A MAP sensor should not appear to be "lazy" or catch up with the throttle movements.

Step

Action

Value

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View References: Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the Throttle Position (TP) Sensor voltage parameter with a scan tool.

Is the voltage less than the specified value when the throttle is fully closed?

0.4 V

Go to Step 3

Go to Step 4

3

  1. Observe the TP sensor angle parameter with a scan tool.
  2. Monitor the scan tool while slowly depressing the accelerator pedal to wide open throttle (WOT), then slowly release the pedal. Repeat the procedure several times.

Does the TP angle increase steadily when the accelerator pedal is depressed to more than the first specified value, and decrease steadily, returning to less than the second specified value when the pedal is released?

85%

15%

Go to Step 5

Go to Step 18

4

Inspect the throttle body for the following conditions:

    • A binding or damaged linkage
    • A binding or damaged throttle cable
    • A binding or damaged cruise control cable

Did you find and correct the condition?

--

Go to Step 38

Go to Step 18

5

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 manifold absolute pressure (MAP) sensor pressure can be observed with a scan tool?

--

Go to Step 6

Go to Step 7

6

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the MAP sensor pressure parameter with a scan tool.
  3. Observe the MAP sensor pressure parameter 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 8

Go to Step 13

7

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 parameter with a scan tool.
  3. The MAP sensor pressure should be within the range specified for your altitude.

Does the MAP sensor indicate the correct barometric pressure?

--

Go to Step 8

Go to Step 13

8

Start the engine while observing the MAP sensor pressure parameter with the scan tool.

Does the MAP sensor pressure parameter change while starting the engine?

--

Go to Step 9

Go to Step 12

9

With the engine running, snap the throttle while observing the MAP sensor pressure parameter on the scan tool.

Does the MAP sensor pressure parameter change rapidly when the throttle position changes?

--

Go to Step 10

Go to Step 12

10

  1. Allow the engine to reach operating temperature.
  2. Ensure that the transaxle is in Park or Neutral.
  3. Turn OFF all of the accessories.
  4. Allow the engine to idle.
  5. Observe the MAP sensor pressure parameter with a scan tool.

Is the MAP sensor pressure within the specified range?

12-96 kPa

Go to Intermittent Conditions

Go to Step 11

11

Test for the following conditions:

    • Engine vacuum leaks
    • Restricted exhaust--Refer to in Engine Exhaust.
    • Worn piston rings--Refer to in Engine Mechanical.
    • Incorrect cam timing--Refer to in Engine Mechanical for the correct timing.

Did you find and correct the condition?

--

Go to Step 38

Go to Step 13

12

  1. Turn OFF the ignition.
  2. Remove the MAP sensor from the vacuum source.
  3. Inspect the port for the following conditions:
  4. • Vacuum restrictions
    • Vacuum leaks

Did you find and correct the condition?

--

Go to Step 38

Go to Step 13

13

  1. Turn OFF the ignition.
  2. Disconnect the MAP sensor electrical connector.
  3. Turn ON the ignition.
  4. Observe the MAP sensor pressure parameter with a scan tool.

Is the pressure less than the specified value?

12 kPa

Go to Step 14

Go to Step 23

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 in Wiring Systems.

Is the voltage more than the specified value?

5.2 V

Go to Step 24

Go to Step 15

15

Probe the 5-volt reference circuit of the MAP sensor with a test lamp that is connected to a good ground.

Is the test lamp OFF?

--

Go to Step 25

Go to Step 16

16

  1. Connect a 3-amp fused jumper wire between the MAP sensor 5-volt reference circuit and the MAP sensor signal circuit.
  2. Observe the MAP sensor pressure parameter with a scan tool.

Is the pressure more than the specified value?

12 kPa

Go to Step 17

Go to Step 26

17

  1. Remove the jumper wire.
  2. Connect a jumper wire between each of the terminals in the MAP sensor harness connector and the corresponding terminal at the MAP sensor. Refer to Using Connector Test Adapters in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the low reference circuit of the MAP sensor, at the jumper wire terminal, to a good ground with a DMM. Refer to Measuring Voltage Drop in Wiring Systems.

Is the voltage more than the specified value?

0.2 V

Go to Step 27

Go to Step 32

18

  1. Turn OFF the ignition.
  2. Disconnect the TP sensor.
  3. Turn ON the ignition.
  4. Observe the TP sensor voltage parameter with a scan tool.

Is the voltage less than the specified value?

0.2 V

Go to Step 19

Go to Step 28

19

Measure the voltage from the TP sensor 5-volt reference circuit to a good ground.

Is the voltage more than the specified value?

5.2 V

Go to Step 24

Go to Step 20

20

Probe the 5-volt reference circuit of the TP sensor with a test lamp that is connected to a good ground.

Is the test lamp OFF?

--

Go to Step 29

Go to Step 21

21

  1. Connect a 3-amp fused jumper between the TP sensor 5-volt reference circuit and the TP sensor signal circuit.
  2. Observe the TP sensor angle parameter with a scan tool.

Is the TP sensor angle more than the specified value?

0%

Go to Step 22

Go to Step 30

22

  1. Remove the jumper wire.
  2. Connect a jumper wire between each of the terminals in the TP sensor harness connector and the corresponding terminal at the TP sensor. Refer to Using Connector Test Adapters in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the low reference circuit of the TP sensor, at the jumper wire terminal, to a good ground with a DMM. Refer to Measuring Voltage Drop in Wiring Systems.

Is the voltage more than the specified value?

0.2 V

Go to Step 31

Go to Step 33

23

Test the MAP sensor signal circuit 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 38

Go to Step 37

24

Test all of the 5-volt reference circuits 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 38

Go to Step 37

25

Test the 5-volt reference circuit of the MAP sensor for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 38

Go to Step 34

26

Test the MAP sensor signal circuit for the following conditions:

    • An open
    • A short to ground
    • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 38

Go to Step 34

27

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

Did you find and correct the condition?

--

Go to Step 38

Go to Step 34

28

Test the TP sensor signal circuit 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 38

Go to Step 37

29

Test the 5-volt reference circuit of the TP sensor for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 38

Go to Step 34

30

Test the TP sensor signal circuit for the following conditions:

    • An open
    • A short to ground
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 38

Go to Step 34

31

Test the low reference circuit of the TP sensor for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 38

Go to Step 34

32

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 38

Go to Step 35

33

Test for an intermittent and for a poor connection at the TP 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 38

Go to Step 36

34

Test for an intermittent and for a poor connection at the engine control module (ECM). 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 38

Go to Step 37

35

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

Did you complete the replacement?

--

Go to Step 38

--

36

Replace the TP sensor. Refer to Throttle Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 38

--

37

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 38

--

38

  1. Clear the DTCs with a 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 39

39

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK