GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2003 🢒 Bravada 🢒 Engine 🢒 Engine Controls - 4.2L 🢒 DTC P0105

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 MAP sensor has the following circuits:

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

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM, also, provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM 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 in order 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 engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.

The PCM calculates a predicted value for the MAP sensor based on throttle position (TP) and engine speed. The PCM then compares the predicted value to the actual MAP sensor signal. If the PCM detects that the MAP sensor signal is not within the predicted range, DTC P0105 sets.

Conditions for Running the DTC
    • DTC P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0336, P0340, P0341, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0507, P0740, P0741, P0742, P1120, P1220, P1221, P1271, P1280, P1441, P1512, P1514, P1516, P1635, P1639, P1680, P1681, or P1860 are not set.
    • The engine run time is more than 40 seconds.
    • The change in engine speed is less than 50 RPM.
    • The engine speed is between 600-6,375 RPM.
    • The torque converter clutch (TCC) is stable to within 2.5 percent.
    • The above conditions are met for 1.5 seconds.

Conditions for Setting the DTC

The PCM detects that the MAP sensor voltage is not within the predicted range for more than 14 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. This step tests the ability of the MAP sensor to respond to an increase in engine vacuum.

    3.

  3. This step tests for a proper MAP sensor pressure with an applied vacuum.

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-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Inspect for the following conditions:

    • Vacuum hoses that are disconnected, damaged, or incorrectly routed
    • Manifold absolute pressure (MAP) sensor seal missing or damaged
    • Restrictions in the MAP sensor vacuum source
    • Intake manifold vacuum leaks

Did you find and correct the condition?

--

Go to Step 25

Go to Step 3

3

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 4

Go to Step 5

4

  1. 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 6

Go to Step 11

5

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 6

Go to Step 11

6

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

Does the MAP sensor pressure change?

--

Go to Step 7

Go to Step  11

7
  1. Turn OFF the ignition.
  2. Remove the MAP sensor from the intake manifold. Leave the MAP sensor connected to the electrical harness.
  3. Connect a hand vacuum pump to the MAP sensor port.
  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 hand vacuum pump in 1 in Hg increments until 15 in Hg is reached. Each 1 in Hg should decrease MAP sensor pressure by 3-4 kPa.

Is the decrease in MAP sensor pressure consistent?

--

Go to Step  8

Go to Step 11

8

  1. Observe the MAP sensor pressure with the scan tool.
  2. Apply vacuum with the hand vacuum pump until 20 in Hg is reached.

Is the MAP sensor pressure less than the specified value?

34 kPa

Go to Step 9

Go to Step 11

9
  1. Observe the MAP sensor pressure with the scan tool.
  2. Disconnect the hand vacuum pump from the MAP sensor.

Does the MAP sensor pressure return to the original reading observed in Step 4 or Step 5?

--

Go to Step 10

Go to Step 23

10

Inspect for the following conditions:

    • Incorrect cam timing--Refer to Camshaft Timing Chain, Sprocket, and Tensioner Replacement 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 25

Go to Intermittent Conditions

11
  1. Disconnect the MAP sensor electrical connector.
  2. Observe the MAP sensor voltage with the scan tool.

Is the voltage less than the specified value?

0.3 V

Go to Step 12

Go to Step 16

12

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 17

Go to Step 13

13

Probe the 5-volt reference circuit of the MAP sensor with a test lamp that is connected to a good ground. Refer to Circuit Testing and Probing Electrical Connectors in Wiring Systems.

Is the test lamp OFF?

--

Go to Step 18

Go to Step 14

14
  1. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the MAP sensor and the signal circuit of the MAP sensor.
  2. Observe the MAP sensor voltage with the scan tool.

Is the voltage more than the specified value?

4.9 V

Go to Step 15

Go to Step 19

15
  1. Turn OFF the ignition.
  2. Remove the jumper wire.
  3. 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.
  4. Turn ON the ignition, with the engine OFF.
  5. 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 20

Go to Step 21

16

Important: Disconnecting the PCM may eliminate the short during testing.

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 24

17

Important: Disconnecting the PCM may eliminate the short during testing.

Test all of the 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 25

Go to Step 24

18

Test the 5-volt reference circuit between the PCM and 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 25

Go to Step 22

19

Test the MAP sensor signal circuit between the PCM and the MAP sensor for the following conditions:

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

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 22

20

Test the low reference circuit between the PCM and 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 25

Go to Step 22

21

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 25

Go to Step 23

22

Test for an intermittent and for a poor connection at the PCM. 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 25

Go to Step 24

23

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

Did you complete the replacement?

--

Go to Step 25

--

24

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 25

--

25
  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 26

26

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