GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 L200/LW200 🢒 Engine 🢒 Engine Electrical 🢒 DTC P0105

Object Number: 1246134 Size: MF
Engine Controls Component Views
Engine Controls Schematics

Circuit Description

The powertrain control module (PCM) supplies a 5-volt reference circuit and a low reference circuit to both the throttle position (TP) sensor and the manifold absolute pressure (MAP) sensor. The TP sensor sends a voltage signal back to the PCM relative to the throttle plate opening, and the MAP sensor sends a voltage signal back to the PCM relative to the intake manifold pressure. The PCM can detect if the TP sensor or the MAP sensor are out of range by comparing the two values against the high and low limits and engine speed defined within the engine calibration. If the TP or the MAP are not within the expected limits of the engine calibration, DTC P0105 sets.

Conditions for Running the DTC
    • DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0340, P0341, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0507, P1133, P1134, P1441 are not set.
    • The engine speed is between 600-6,375 RPM.
    • The change in engine speed is less than 50 RPM.
    • The engine run time is more than 40 seconds.
    • The torque converter clutch (TCC) is stable to within 1.3 percent, if equipped.
    • The idle air control (IAC) valve is stable to within 5 counts.
    • The change in throttle position is less than 2 percent.

Conditions for Setting the DTC

The MAP sensor or the TP sensor is out of an expected range defined by the engine calibration for 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.

Diagnostic Aids
    • If a DTC P0105 cannot be duplicated, the information included in the Freeze Frame/Failure Records data can be useful in diagnosing an intermittent condition.
    • A TP sensor that is stuck may attempt to auto zero every time the engine runs. An indication if this happens is the TP percentage will be 0 percent and TP voltage will be high.
    • If the condition is intermittent, refer to Intermittent Conditions .

Test Description

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

  1. If any of these DTCs are set, this indicates a failed component or a shorted circuit affecting the 5-volt reference system voltage.

    2.

  2. 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.

    3.

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

    4.

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

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-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

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

Is DTC P0452, P0453, or P0530 also set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the throttle position (TP) sensor voltage with a scan tool.

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

0.85 V

Go to Step 4

Go to Step 5

4
  1. Observe the TP sensor angle with a scan tool.
  2. Monitor the scan tool while slowly depressing the accelerator pedal to the floor, slowly releasing 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?

98%

1%

Go to Step 6

Go to Step 18

5

Inspect the throttle body for the following conditions:

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

Did you find and correct the condition?

--

Go to Step 34

Go to Step 18

6

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 7

Go to Step 8

7
  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 9

Go to Step 14

8

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 9

Go to Step 14

9

Start the engine while observing the MAP sensor value with the scan tool.

Does the MAP sensor value change while starting the engine?

--

Go to Step 10

Go to Step 13

10

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

Does the MAP sensor value change rapidly when the throttle position changes?

--

Go to Step 11

Go to Step 13

11
  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 with a scan tool.

Is the MAP sensor pressure within the specified range?

19-42 kPa

Go to Diagnostic Aids

Go to Step 12

12

Test for the following conditions:

    • Engine vacuum leaks
    • Restricted exhaust--Refer to Restricted Exhaust in Engine Exhaust.
    • Worn piston rings--Refer to Engine Compression Test in Engine Mechanical.
    • Incorrect cam timing--Refer to Camshaft Timing Chain, Sprocket, and Tensioner Replacement in Engine Mechanical for the correct timing.

Did you find and correct the condition?

--

Go to Step 34

Go to Step 14

13
  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 34

Go to Step 14

14
  1. Turn OFF the ignition.
  2. Disconnect the MAP sensor electrical connector.
  3. Turn ON the ignition.
  4. Observe the MAP sensor voltage with a scan tool.

Is the voltage less than the specified value?

0.2 V

Go to Step 15

Go to Step 21

15
  1. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Note the measurement as Supply voltage.
  2. 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.
  3. Measure the amperage with the DMM. Note the measurement as Amperage.

Is the amperage at the specified value?

0 mA

Go to Step 23

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.
  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 22

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

Is the result more than the specified value?

5 ohms

Go to Step 24

Go to Step 28

18

  1. Disconnect the TP sensor.
  2. Measure the voltage from the 5-volt reference circuit of the TP sensor to a good ground with a DMM. Note the measurement as Supply voltage.

Is the voltage more than the specified value?

5.2 ohms

Go to Step 25

Go to Step 19

19

  1. Connect a test lamp and a DMM in series between the 5-volt reference circuit and the low reference circuit of the TP sensor at the harness connector.
  2. Measure the amperage with the DMM. Note the measurement as Amperage.
  3. Remove the DMM from the circuit.
  4. Connect the test lamp between the 5-volt reference circuit and the low reference circuit of the TP sensor at the harness connector.
  5. 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.
  6. Subtract the Load voltage drop from the Supply voltage. Note the result as Supply voltage drop.
  7. Divide the Supply voltage drop by the Amperage.

Is the result more than the specified value?

5 ohms

Go to Step 26

Go to Step 20

20
  1. Measure the voltage from the low reference circuit of the TP sensor at the test lamp to a good ground with the DMM. Note the result as Low reference voltage drop.
  2. Divide the Low reference voltage drop by the Amperage.

Is the result more than the specified value?

5 ohms

Go to Step 27

Go to Step 29

21

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 34

Go to Step 33

22

Test the 5-volt reference circuit of 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 34

Go to Step 30

23

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

Did you find and correct the condition?

--

Go to Step 34

Go to Step 30

24

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

Did you find and correct the condition?

--

Go to Step 34

Go to Step 30

25

Test the 5-volt reference circuit of the TP 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 34

Go to Step 33

26

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

Did you find and correct the condition?

--

Go to Step 34

Go to Step 30

27

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

Did you find and correct the condition?

--

Go to Step 34

Go to Step 30

28

Test for poor connections 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 34

Go to Step 31

29

Test for poor connections at the TP sensor electrical connector. 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 34

Go to Step 32

30

Test for poor connections 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 34

Go to Step 33

31

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

Did you complete the replacement?

--

Go to Step 34

--

32

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

Did you complete the replacement?

--

Go to Step 34

--

33

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 34

--

34
  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 35

35

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