For 1990-2009 cars
Engine Controls Component Views
Engine Data Sensors (1 of 2)
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Powertrain Control Module Connector End Views
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice

### Circuit Description

The throttle position (TP) sensor is a potentiometer whose resistance value changes along with the throttle valve position. The powertrain control module (PCM) provides a 5 volt reference voltage to the TP sensor. The PCM reads the voltage across the TP sensor and uses the voltage to calculate the percentage of throttle valve opening. The TP sensor resistance decreases as the throttle valve opening increases. When the TP sensor resistance decreases the voltage being monitored by the PCM increases. The TP sensor resistance increases when the throttle valve opening decreases, therefore the voltage being monitored by the PCM will decrease.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

The TP sensor input to the PCM is less than 0.1 volts.

OR:

The TP sensor input to the PCM is more than 4.9 volts.

### Action Taken When the DTC Sets

• | The PCM illuminates the malfunction indicator lamp (MIL).

• | The PCM stores the conditions that were present when the DTC set as Freeze Frame data.

• | The TP sensor angle will default to 0 percent.

### Conditions for Clearing the MIL/DTC

• | The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run, and the fault condition is no longer present.

• | A DTC clears after 40 consecutive warm-up cycles have occurred without a fault.

• | A DTC can be cleared by using the scan tool Clear DTC Information function.

### Diagnostic Aids

If DTCs P0110, P0115, and P0120 are also set, the malfunction may be in the sensor ground circuit.

The scan tool will typically display a TP angle of 8-10 percent at idle, and 76-77 percent at wide open throttle (WOT).

An intermittent malfunction may be caused by fault in the TP sensor electrical circuit. Inspect the wiring harness and components for any of the following conditions:

• | Any backed-out terminals

• | Any improper mating of terminals

• | Any broken electrical connector locks

• | Any improperly formed or damaged terminals

• | Any faulty terminal-to-wire connections

• | Any physical damage to the wiring harness

• | A broken wire inside the insulation

• | Any corrosion of the electrical connections, the splices, or the terminals

Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Wiring Systems.

The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

### Test Description

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

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

2. This step checks whether the malfunction is a high input condition.

3. This step checks whether the malfunction is a low input condition.

4. This step determines if DTC P0120 is the result of a hard failure or an intermittent condition.

5. The scan tool should read 0 percent , if the reading is more check for a short to battery voltage in the TP sensor input circuit.

6. When the 5 volt reference is jumpered to the TP input circuit, the scan tool parameter should read 100 percent.

7. When the TP sensor input circuit is jumpered to battery voltage , the scan tool parameter should read 100 percent.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | With the throttle closed, select the TP sensor parameter on the scan tool. Is the TP sensor percentage more than the specified value? | 25% | Go to Step 5 | Go to Step 3
3 | Monitor the TP sensor with the throttle closed. Is the TP sensor percentage less than the specified value? | 6% | Go to Step 12 | Go to Step 4
4 |

1. Perform the scan tool Clear DTC Information function.
2. Place the vehicle into Check Mode, using the scan tool.
3. Operate the vehicle within the Freeze Frame conditions as specified.

Does DTC P0120 set?

--

Go to Step 2

Go to Diagnostic Aids

5 |

1. Turn OFF the ignition.
2. Disconnect the TP sensor electrical connector.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the TP sensor on the scan tool.

Is the TP sensor percentage more than the specified value?

0%

Go to Step 7

Go to Step 6

6 | Probe the TP sensor ground circuit on the harness side, using a test lamp connected to battery voltage. Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 10
7 |

1. Turn OFF the ignition, disconnect the PCM connector at the PCM.
2. Turn ON the ignition, with the engine OFF.
3. Check for a short to voltage in the TP sensor input circuit.
4. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 20

8 |

1. Turn ON the ignition, with the engine OFF.
2. Use a DMM in order to measure the voltage at the reference voltage circuit on the harness side.

Does the voltage equal the specified value?

5.0 V

Go to Step 9

Go to Step 11

9 | Check for a faulty electrical connection at the TP sensor and the PCM. Replace the terminals if necessary. Was a repair necessary? | -- | Go to Step 21 | Go to Step 18
10 |

1. Turn OFF the ignition.
2. Disconnect the PCM connector at the PCM.
3. Check for an open in the TP sensor ground circuit.
4. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 20

11 |

1. Turn OFF the ignition.
2. Disconnect the PCM electrical connector at the PCM.
3. Check the reference voltage circuit for an open or a short.
4. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 20

12 |

1. Disconnect the TP sensor electrical connector.
2. Jump the 5 volt reference circuit and the TP sensor input circuit together at the TP sensor harness connector
3. Select the TP sensor on the scan tool.

Is the TP sensor percentage more than the specified value?

90%

Go to Step 18

Go to Step 13

13 |

1. Connect a test lamp between battery voltage and the TP sensor input circuit at the TP sensor harness connector.
2. Monitor the TP sensor on the scan tool.

Is the TP sensor percentage more than the specified value?

90%

Go to Step 14

Go to Step 16

14 |

1. Turn OFF the ignition.
2. Disconnect the PCM electrical connector at the PCM.
3. Check the 5 volt reference circuit for an open or a short.
4. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 15

15 |

1. Check the 5 volt reference circuit for a faulty electrical connection at the TP sensor and the PCM.
2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 20

16 |

1. Turn OFF the ignition.
2. Disconnect the PCM connector at the PCM and check the TP input circuit for an open or a short to ground. Ensure that the input circuit is not shorted to the sensor ground circuit.
3. Repair the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 17

17 |

1. Check the TP sensor input circuit for a faulty connection at the PCM.
2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 20

18 |

1. Check the TP sensor terminals and the terminal connections.
2. Repair as necessary. Refer to Connector Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 21

Go to Step 19

19 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Is the action complete? | -- | Go to Step 21 | --
20 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 21 | --
21 |

1. Perform the scan tool Clear DTC Information function and road the vehicle within the Freeze Frame conditions that set the DTC.
2. Review the scan tool data and check for DTCs. The repair is complete if no DTCs are stored.

Are any DTCs displayed on scan tool?

--

Go to Diagnostic Trouble Code (DTC) List

System OK