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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 Accessories 🢒 Navigation Systems 🢒 DTC P0106

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 engine control module (ECM) supplies a regulated 5 volts to the sensor on the 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM 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 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 ECM uses the MAP sensor in order to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 19 kPa when pressures are low, to as much as 104 kPa when pressures are high, depending on the BARO.

Within the ECM, the diagnostic has the ability to determine an inaccurate input from the MAP sensor. Calibrated within the diagnostics are estimates for MAP based on throttle position and engine speed. The diagnostic compares the estimated value to the actual sensor input. If the ECM 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 Barometric Pressure (BARO) Sensor Performance

Conditions for Running the DTC
    • DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0122, P0123, P0222, P0223, P0506, P0507, P2101, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2138, or P2176 are not set.
    • The engine speed is between 600-6,300 RPM.
    • DTC P0106 runs on a 25 millisecond loop.
    • DTC P0106 runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the MAP sensor pressure is not within a calibrated limit of the estimated value for more than 3 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.

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.

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

    3.

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

    4.

  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 Engine Control Module Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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

Is DTC P2095 or P0335 also set?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Inspect for the following conditions:
    3. • 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 30

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. Refer to Altitude Versus Barometric Pressure .
  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 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.

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 28

11

Inspect for the following conditions:

    • High resistance on the crankshaft position (CKP) sensor low reference or 12-volt reference circuits
    • Poor connections at the CKP sensor
    • Incorrect cam timing--Refer to Camshaft Timing Drive Chain Alignment Diagram in Engine Mechanical for the correct timing.
    • Restricted exhaust flow--Refer to Restricted Exhaust in Engine Exhaust.
    • Worn piston rings--Refer to Engine Compression Test in Engine Mechanical.

Did you find and correct the condition?

--

Go to Step 30

Go to Intermittent Conditions

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

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?

20 kPa

Go to Step 14

Go to Step 20

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. Note the measurement as supply voltage.

Is the voltage more than the specified value?

5.2 V

Go to Step 21

Go to Step 15

15

Is the voltage more than the specified value?

4.8 V

Go to Step 16

Go to Step 22

16

  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 25

Go to Step 17

17

  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.

    4. 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 23

Go to Step 18

18

  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.

    2. 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 26

Go to Step 19

19
  1. Remove the test lamp.
  2. Connect a 3-amp fused jumper wire between the 5-volt reference circuit and the signal circuit of the MAP sensor, at the harness connector.
  3. Observe the MAP sensor parameter with the scan tool.

Is the pressure more than the specified value?

103 kPa

Go to Step 28

Go to Step 24

20

Test the MAP sensor signal circuit between the engine control module (ECM) and the MAP sensor 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 30

Go to Step 27

21

Test all branches of the 5-volt reference circuit that are shared with the MAP sensor 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 30

Go to Step 27

22

Test the 5-volt reference circuit between the ECM and the MAP sensor for an open or for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 27

23

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

Did you find and correct the condition?

--

Go to Step 30

Go to Step 27

24

Test the MAP sensor signal circuit between the ECM and the MAP sensor for the following:

    • 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 30

Go to Step 27

25

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

Did you find and correct the condition?

--

Go to Step 30

Go to Step 27

26

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

Did you find and correct the condition?

--

Go to Step 30

Go to Step 27

27

Test for shorted terminals and for poor connections at the 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 30

Go to Step 29

28

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

Did you complete the replacement?

--

Go to Step 30

--

29

Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 30

--

30
  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 31

31

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 in Vehicle DTC Information

System OK