For 1990-2009 cars
Engine Controls Components
Cell 23: Engine Data Sensors
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views With EGR
Handling ESD Sensitive Parts Notice

### Circuit Description

The Powertrain Control Module (PCM) supplies a 5.0-volt reference signal and a ground 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, a DTC P0105 is set. During the DTC P0105 test, the actual MAP value is compared to a high limit threshold and low limit threshold for any speed and load in which the vehicle is operated. If the actual MAP value is more than the high limit, or less than the low limit, a malfunction is indicated.

### Conditions for Running the DTC

DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0131, P0132, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0341, P0342, P0440, P0442, P0502, P0506, P0507, P1441 not set.

• | Engine run time is greater than 40 seconds.

• | Engine speed is between 600 RPM and 6375 RPM.

• | Torque Converter Clutch (TCC) is stable to within 2.5 percent.

• | Engine speed is stable to within 50 RPM.

• | IAC valve is stable to within 5 counts.

• | The TP sensor is stable to within 2 percent

• | The above conditions are present for 1.5 seconds.

### Conditions for Setting the DTC

The MAP sensor is out of an expected range defined on the engine calibration. for 14 out of 16 seconds.

### Action Taken When the DTC Sets

• | The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the malfunction present.

• | The PCM will record the operating conditions at the time that the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers.

• | A history DTC stores.

### Conditions for Clearing the MIL/DTC

• | The MIL will turn OFF after three 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.

• | The MIL/DTCs can be cleared by using the scan tool.

### Diagnostic Aids

• | With the ignition turn 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 PCM as an indication of the vehicle barometric pressure. Comparison of this reading with a known good vehicle with the same sensor is a good way to check the accuracy of a suspect sensor. Readings should be the same +/-0.4 volt.

• | The MAP sensor vacuum source should be thoroughly checked for restrictions at the intake manifold.

• | A TP sensor that is stuck will attempt an auto zero every time the engine runs.

• | If a DTC P0105 cannot be duplicated, the information included in the Freeze Frame/Failure Records data can be useful. Use the scan tool DTC information data in order to determine the status of the DTC.

1. A DTC P0105 may set due to any condition that may cause an unreasonably high or low map value including the following engine conditions:

• | Incorrect cam timing

• | Restricted exhaust

• | Worn piston rings

• | Low fuel pressure

2. 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.
3. Using a DMM in order to check 5.0 volt reference circuits may not detect small amounts of resistance within the malfunctioning circuit. Connecting a jumper wire from the 5.0 volt reference circuit to the signal circuit detects the small amounts of resistance.
4. Certain conditions can produce normal results when probed, but can cause a bad reading when connected. Check for the following conditions on the TP and MAP sensor electrical connectors:

- | Spread terminals

- | Poor electrical terminal connections

5. The MAP sensor needs a dedicated vacuum source. Check the MAP sensor and the MAP sensor vacuum source for the following conditions:

- | Vacuum leak

- | Split vacuum hose

- | Shared vacuum source

### Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored in the scan tool for later reference.

2. The TP sensor may be able to auto zero itself after several engine starts if it is stuck but may not be able to reach its range near 100 percent. The TP angle should increase steadily. If the voltage value spikes high or low, consider the test failed.

3. The TP sensor has an auto zeroing feature. If the voltage reading is between 0.2 to 0.9 volts, the PCM will assume the TP sensor is at a closed throttle position (0%). If the reading is out of the auto zeroing range at closed throttle, look for a binding or damaged linkage.

4. A MAP sensor that displays a BARO value that does not appear normal for the altitude the vehicle is located, the MAP sensor is considered malfunctioning.

5. 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.

6. A normal MAP sensor will react as quickly to the throttle changes as they can be made. A MAP sensor should not appear to be lazy or catch up with the throttle movements.

7. The MAP sensor vacuum source should be thoroughly checked for restrictions. This step checks if the reason for no MAP change was due to a malfunctioning sensor or vacuum source problem to the sensor.

8. A short to voltage in the signal circuit would most likely be caused by the 5.0 volt reference circuit. Check for the 5.0 volt reference circuit for being pinched with the signal circuit.

9. Spread terminals or poor electrical connections can produce normal results when probed but cause incorrect readings when connected. Be sure to check all terminals for this condition.

10. A short to voltage in the signal circuit would most likely be caused by the 5.0 volt reference circuit. Check for the 5.0 volt reference circuit for being pinched with the signal circuit.

11. Spread terminals or poor electrical connections can produce normal results when probed but cause incorrect readings when connected. Be sure to check all terminals for this condition.

12. Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be preformed. Refer to the latest Techline information for programming procedures and also refer to the Crankshaft Position System Variation Learn .

13. If no malfunctions have been found at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.

#### DTC P0105 -- TP/MAP Sensor Performance

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Are any other MAP, TP, A/C or Fuel Tank Pressure Sensor DTCs set or last test failed? | -- | Diagnose the other DTCs first | Go to Step 3
3 |

1. Perform a visual/physical inspection of the MAP sensor and the TP sensor areas.
2. Repair if a malfunction is found.

Was a malfunction found?

--

Go to Step 28

Go to Step 4

4 | Does the scan tool display a TP voltage below the specified value when the throttle is fully closed? | 0.90 V | Go to Step 5 | Go to Step 6
5 |

1. Select the TP angle parameter on the scan tool.
2. Monitor the scan tool while slowly depressing the accelerator pedal to the floor and then slowly release the pedal (repeat the procedure several times).

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

98%

1%

Go to Step 7

Go to Step 19

6 |

1. Check the throttle body for the following conditions:

• | Binding linkage

• | damaged linkage

• | incorrect air rate adjustment

2. Repair if found malfunctioning

Was a repair necessary?

--

Go to Step 28

Go to Step 19

7 | Compare the BARO reading with a known good vehicle. The BARO value should be within the specified value of the other vehicle. Is the BARO reading normal for your altitude? | 3 kPa | Go to Step 8 | Go to Step 11
8 | Start the engine while watching the MAP sensor value with the scan tool. Does the MAP sensor value change while starting the engine? | -- | Go to Step 9 | Go to Step 10
9 | With the engine still running, snap the throttle while watching the MAP sensor display on the scan tool. Does the MAP sensor value change rapidly when the throttle position changes? | -- | Go to Step 28 | Go to Step 10
10 |

1. Turn OFF the engine leaving the ignition switch ON.
2. Remove the MAP sensor or hose (if applicable) from the manifold port.
3. Inspect the port and hose for the following conditions:

• | Vacuum restrictions

• | Vacuum leaks

4. Repair the condition as necessary.
5. Ensure that the vacuum source is used only for the MAP sensor.

Was a repair necessary?

--

Go to Step 28

Go to Step 11

11 |

1. Turn OFF the ignition switch.
2. Disconnect the MAP sensor electrical connector.
3. Turn ON the ignition switch.
4. Observe the MAP sensor value on the scan tool.

Does the scan tool read the specified value?

0.0 V

Go to Step 12

Go to Step 13

12 |

1. Connect a fused jumper to the MAP sensor 5.0 volt reference circuit.
2. Connect the other end of the fused jumper to the MAP sensor signal circuit.

Does the scan tool read the specified value?

5.0 V

Go to Step 14

Go to Step 15

13 |

1. Turn OFF the ignition switch.
2. Disconnect the PCM electrical connectors.
3. Turn ON the ignition switch leaving the engine OFF.
4. Check the MAP sensor signal for a short to voltage.
5. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 27

14 |

1. Connect a test light to B+.
2. Probe the MAP sensor ground circuit with the test light.

Does the test light illuminate?

--

Go to Step 16

Go to Step 18

15 |

1. Check the MAP sensor 5.0 reference circuit at the PCM electrical connector for the following conditions

• | Poor electrical terminal tension

• | Poor electrical connection

2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 27

16 |

1. Check the MAP sensor electrical connector for the following conditions:

• | Poor electrical terminal tension

• | Poor electrical connection

2. Repair the MAP sensor electrical connector as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 17

17 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Is the action complete? | -- | Go to Step 28 | --
18 |

1. Check the MAP ground circuit for the following conditions:

- | Poor electrical terminal tension

- | Poor electrical connection

2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 27

19 |

1. Turn OFF the ignition switch
2. Disconnect the TP sensor electrical connector.
3. Turn ON the ignition switch.
4. Observe the TP sensor value on the scan tool.

Does the scan tool read the specified value?

0.0 V

Go to Step 20

Go to Step 21

20 |

1. Connect a fused jumper to the TP sensor 5 volt reference circuit.
2. Connect the other end of the fused jumper to the TP sensor signal circuit.

Does the scan tool read the specified value?

5.0 V

Go to Step 22

Go to Step 23

21 |

1. Turn OFF the ignition switch.
2. Disconnect the PCM electrical connectors.
3. Turn ON the ignition switch leaving the engine OFF.
4. Check the TP signal circuit for a short to voltage
5. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 27

22 |

1. Connect a test light to B+.
2. Probe the TP sensor ground circuit at the TP sensor electrical connector with the test light.

Does the test light illuminate?

--

Go to Step 24

Go to Step 25

23 |

1. Check the TP sensor 5.0 volt or signal circuit for the following conditions:

• | Poor electrical terminal tension

• | Poor electrical connection

2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 27

24 |

1. Check the TP sensor electrical connector for the following conditions:

• | Poor electrical terminal tension

• | Poor electrical connection

2. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 25

25 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Is the action complete? | -- | Go to Step 28 | --
26 |

1. Check the TP sensor ground circuit for the following conditions:

• | Poor electrical connection

• | High resistance at the TP sensor electrical connector.

2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 28

Go to Step 27

27 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 28 | --
28 |

1. Clear DTCs with a scan tool.
2. Start the engine.
3. Idle at normal operating temperature.
4. Operate vehicle within the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic ran and passed?

Go to Step 29

Go to Step 2

29 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK, refer to Diagnostic Aids