For 1990-2009 cars

### Circuit Description

The throttle position (TP) sensor is mounted on the throttle body assembly. The sensor is actually 2 individual TP sensors within 1 housing. Two separate signal circuits , low reference circuits, and 5-volt reference circuits are used in order to connect the TP sensor assembly to the throttle actuator control (TAC) module. The 2 sensors have opposite functionality. The TP sensor 1 signal voltage is pulled up to reference voltage when the throttle opens, from below 1 volt at closed throttle to above 3.5 volts at wide open throttle (WOT). The TP sensor 2 signal voltage is pulled down to low reference from around 3.8 volts at closed throttle to below 1 volt at WOT. TP sensor 1 and APP sensor 1 share a 5-volt reference circuit that is connected within the TAC module. TP sensor 2 and APP sensor 2 share a 5-volt reference circuit that is connected within the TAC module. If an out of range condition is detected with the TP sensor 1, this diagnostic trouble code (DTC) will set and the Reduced Engine Power message will be displayed.

### Conditions for Running the DTC

• | DTCs P1517 and P1518 are not set.

• | The ignition switch is in the crank or the run position.

• | The ignition voltage is greater than 5.23 volts.

### Conditions for Setting the DTC

• | The TP sensor 1 signal voltage is less than 0.13 volts or greater than 4.87 volts.

• | All of the above conditions are present for less than 1 second.

### Action Taken When the DTC Sets

• | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

• | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.

• | The control module commands the TAC system to operate in the Reduced Engine Power mode.

• | A message center or an indicator displays Reduced Engine Power.

• | Under certain conditions the control module commands the engine OFF.

### 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

• | Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs could be set with no circuit or component conditions found during diagnostic testing.

• | When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture Info.

• | If this DTC is determined to be intermittent, refer to Intermittent Conditions .

### Test Description

The number below refers to the step number on the diagnostic table.

1. When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture Info.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic References: 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 | Is DTC P1515, P1516, or P1518 also set? | -- | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3
3 |

1. Turn OFF the ignition.
2. Remove the air inlet duct from the throttle body assembly.
3. Disconnect the throttle actuator motor harness connector.
4. Turn ON the ignition, with the engine OFF.
5. Close the throttle blade completely by hand while observing the TP sensor 1 voltage on the scan tool.

Does the scan tool indicate TP sensor 1 voltage within the specified values?

0.13-0.67 V

Go to Step 4

Go to Step 8

4 | Open the throttle blade to wide open throttle (WOT) by hand while observing the TP sensor 1 voltage parameter on the scan tool. Does the scan tool indicate TP sensor 1 voltage within the specified values? | 4.09-4.87 V | Go to Step 5 | Go to Step 8
5 |

1. Disconnect the TP sensor harness connector.
2. Disconnect the TAC module harness connector containing the TP sensor circuits.
3. Use a DMM in order to test the TP sensor low reference circuit 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 31

Go to Step 6

6 |

1. Turn OFF the ignition for 15 seconds.
2. Reconnect the TAC module harness connector.
3. Reconnect the throttle actuator motor harness connector.
4. Reinstall the air inlet duct.
5. Turn ON the ignition, with the engine OFF.
6. Select the DTC Info. option on the scan tool.
7. Lightly touch and move the related engine wiring harnesses and connectors for the TP sensor while observing the DTC Info. The DTC will set if an intermittent condition is present. Refer to Connector Repairs and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 31

Go to Step 7

7 |

1. Continue to observe DTC Info.
2. Slowly depress the accelerator pedal to WOT and then slowly return it to the released position 3 times.

Does the scan tool indicate this DTC failed this ignition?

--

Go to Step 26

Go to Diagnostic Aids

8 |

1. Disconnect the TP sensor harness connector.
2. Measure voltage at the TP sensor 1 signal circuit with a DMM connected to ground.

Does the DMM indicate voltage within the specified values?

3.94-6.06 V

Go to Step 13

Go to Step 9

9 |

1. Turn OFF the ignition.
2. Disconnect the TAC module harness connector containing the TP sensor circuits.
3. Turn ON the ignition with the engine OFF.
4. Use a DMM in order to test the TP sensor 1 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 31

Go to Step 10

10 | Use a DMM in order to test the TP sensor 1 signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 11
11 | Use a DMM in order to test the TP sensor 1 signal circuit 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 31 | Go to Step 12
12 |

1. Disconnect the other TAC module harness connector.
2. Use a DMM in order to test for a short between the TP sensor 1 signal circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 31

Go to Step 27

13 | Use a DMM in order to test the TP sensor 1 5-volt reference circuit for voltage. Does the DMM indicate voltage within the specified values? | 3.94-6.06 V | Go to Step 23 | Go to Step 14
14 | Does the DMM indicate voltage greater than the specified value? | 6.06 V | Go to Step 15 | Go to Step 17
15 |

1. Turn OFF the ignition.
2. Disconnect the TAC module harness connector containing the TP sensor circuits.
3. Turn ON the ignition with the engine OFF.
4. Use a DMM in order to test the TP sensor 1 5-volt reference 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 31

Go to Step 16

16 |

1. Turn OFF the ignition.
2. Disconnect the accelerator pedal position (APP) sensor harness connector.
3. Disconnect the other TAC module harness connector.
4. Turn ON the ignition, with the engine OFF.
5. Use a DMM in order to test the APP sensor 1 5-volt reference 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 31

Go to Step 21

17 | Disconnect the APP sensor. Does the DMM indicate voltage less than the specified value? | 3.94 V | Go to Step 18 | Go to Step 29
18 |

1. Disconnect the TAC module harness connector containing the TP sensor circuits.
2. Use a DMM in order to test the TP sensor 1 5-volt reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 31

Go to Step 19

19 | Use a DMM in order to test the TP sensor 1 5-volt reference circuit for a short to ground. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 20
20 | Use a DMM in order to test the APP sensor 1 5-volt reference circuit 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 31 | Go to Step 21
21 | Use a DMM in order to test for a short between the TP sensor 1 5-volt reference circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 22
22 | Use a DMM in order to test for a short between the APP sensor 1 5-volt reference circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 27
23 |

1. Connect a fused jumper between the TP sensor 1 low reference circuit and the TP sensor 1 signal circuit.
2. Use a scan tool in order to observe the TP sensor 1 voltage parameter.

Does the scan tool indicate voltage near the specified value?

0 V

Go to Step 25

Go to Step 24

24 |

1. Turn OFF the ignition.
2. Disconnect the TAC module harness connector containing the TP sensor circuits.
3. Use a DMM in order to test the TP sensor 1 low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 31

Go to Step 27

25 | Inspect for poor connections at the TP sensor harness 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 31 | Go to Step 28
26 | Inspect for poor connections at the APP module harness 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 31 | Go to Step 29
27 | Inspect for a poor connection at the TAC module harness 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 31 | Go to Step 30
28 | Important: The throttle body and the throttle position sensor assembly should be replaced as a unit. Driveability concerns may result if either is replaced individually. Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .

Did you complete the replacement?

--

Go to Step 31

--

29 | Replace the APP sensor. Refer to Accelerator Pedal Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 31 | --
30 | Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement . Did you complete the replacement? | -- | Go to Step 31 | --
31 |

1. Use the scan tool in order to clear the DTCs.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 32

Go to Step 2

32 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List | System OK