For 1990-2009 cars

Schematic Reference: Engine Controls Schematics

### Circuit Description

The Throttle Position (TP) sensor is a potentiometer. The TP sensor is mounted to the right side of the throttle body. The TP sensor provides a voltage signal that changes relative to throttle blade angle. This signal voltage is one of the most important inputs used by the PCM. The TP sensor has a 5.0 volt reference, a ground and a signal circuit.

TP sensor Signal voltage should be about 0.6 volt at idle. The TP sensor voltage should increase to above 4.0 volts at wide open throttle (WOT).

When the PCM senses a signal voltage lower than the normal operating range of the sensor, this DTC will set.

### Conditions for Setting the DTC

• | TP sensor signal voltage is less than 0.2 volts.

• | Condition present for 1 second.

### Action Taken When the DTC Sets

• | The PCM will illuminate the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.

• | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and/or Failure Records.

• | The PCM will use a default TP sensor value.

• | Transmission TCC will not apply.

• | High transmission line pressure.

• | Fixed transmission shift points, hard shifts and no fourth gear in hot mode.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

• | A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• | A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.

• | PCM battery voltage is interrupted.

• | Using a Scan tool.

### Diagnostic Aids

• | An intermittent may be caused by the following:

- | Mis-routed harness.

- | Rubbed through wire insulation.

- | Broken wire inside the insulation.

• | If other DTCs are set that share the same ground and/or 5.0 volt reference circuit, check for faulty connections and for faulty wiring.

• | The PCM 5 volt reference circuits are internally connected within the PCM. If all the TP sensor circuits check to be OK, inspect related 5.0 volt reference circuits.

• | If it is determined that the DTC occurs intermittently, performing the DTC P1122 diagnostic table may isolate the cause of the fault.

For intermittents, refer to Symptoms .

### Test Description

Number(s) below refer to step numbers on the diagnostic table.

1. Determines if the malfunction is present.

2. Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed.

3. Disconnect the EBTCM on vehicles equipped with traction control. This will determine if the short is caused from the EBTCM. After repairs are made, reconnect the EBTCM, clear any DTCs that may have been set when the EBTCM was disconnected.

4. If the scan tool indicates 5.0 volts, the TP sensor circuits and PCM are OK.

5. This step checks the integrity of the TP sensor signal circuit.

6. Disconnecting the PCM will allow using the DVM (J 39200) to check continuity of the circuits. This will aid in locating an open or shorted circuit.

   Refer to Electrical Diagnosis for repair procedures.

7. Disconnecting the PCM will allow using the DVM (J 39200) to check continuity of the circuits. This will aid in locating an open or shorted circuit.

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 |

1. Install the scan tool.
2. Turn the ignition ON, engine OFF.
3. With the throttle closed, monitor the TP sensor display on the Engine 1 Data List of the scan tool.

Is the TP sensor voltage below the specified value?

0.2V

Go to Step 4

Go to Step 3

3 |

1. Turn the ignition ON, engine OFF, review Freeze Frame and/or Failure Records data for this DTC and note parameters.
2. Turn the ignition OFF for 15 seconds.
3. Start the engine and operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in Freeze Frame/Failure Records as possible. Special operating conditions that need to be met before the PCM will run this diagnostic, where applicable, are listed in Conditions for Setting the DTC.
4. Using the scan tool, select DTC, Specific, then enter the DTC number which was set.

Does the scan tool indicate that this diagnostic failed this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4 | Important: This step is only for D and Y cars. Proceed to step 5 If the vehicle is not a D or Y car.

1. Turn the ignition OFF.
2. Disconnect the EBTCM.
3. Turn the ignition ON.

Is the TP sensor voltage still below the specified value?

0.2V

Go to Step 5

Go to Section 5E2 for further diagnosis of the EBTCM

5 |

1. Disconnect the TP sensor electrical connector.
2. Jumper the 5 volt reference circuit and the TP signal together at the TP sensor harness connector.
3. Observe the TP sensor voltage display on the scan tool.

Is the TP sensor voltage above the specified value?

4.7 V

Go to Step 11

Go to Step 6

6 |

1. Connect a test light between B+ and the TP sensor signal circuit at the TP sensor harness connector.
2. Observe the TP sensor voltage display on the scan tool.

Is the TP sensor voltage above the specified value?

4.7V

Go to Step 7

Go to Step 9

7 |

1. Turn the ignition OFF.
2. Disconnect the PCM and check the 5 volt reference circuit for an open or short to ground.
3. If the 5 volt reference circuit is open or shorted to ground, repair circuit as necessary.

Was the 5 volt reference circuit open or shorted to ground?

--

Go to Step 13

Go to Step 8

8 | Check the 5 volt reference circuit for a poor connection at the PCM and replace the terminal if necessary. Refer to Repair Procedures in Electrical Diagnosis (8A Cell 5). Did the terminal require replacement? | -- | Go to Step 13 | Go to Step 12
9 |

1. Turn the ignition OFF.
2. Disconnect the PCM, and check the TP signal circuit for an open, short to ground, or short to the sensor ground circuit.
3. If the TP sensor signal circuit is open or shorted to ground, repair it as necessary. Refer to Repair Procedures in Electrical Diagnosis (8A Cell 5).

Was the TP signal circuit open or shorted to ground?

--

Go to Step 13

Go to Step 10

10 | Check the TP sensor signal circuit for a poor connection at the PCM and replace terminal if necessary. Refer to Repair Procedures in Electrical Diagnosis (8A Cell 5). Did the terminal require replacement? | -- | Go to Step 13 | Go to Step 12
11 | Replace the TP sensor. Refer to Throttle Position Sensor Replacement . Is the action complete? | -- | Go to Step 13 | --
12 | Important:: Replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | Go to Step 13 | --
13 |

1. Using the scan tool, select DTC, Clear Info.
2. Start the engine and idle at normal operating temperature.
3. Select DTC, Specific, then enter the DTC number which was set.
4. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text, if applicable.

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

--

Go to Step 14

Go to Step 2

14 | Using the scan tool, select Capture Info, Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK