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For 1990-2009 cars only

Refer to Engine Controls Schematics

PCM, TP Sensor, TAC Motor, TAC Module


Object Number: 449880  Size: FS
Engine Controls Components
Evaporative Emission Control System Operation Description
Control Module, Cruise Control Switch, APP Sensor
CPP, EBCM, Suspension Control Module, Stoplamp Switch
Handling ESD Sensitive Parts Notice
OBD II Symbol Description Notice
Ground Distribution Schematics
Power Distribution Schematics
.

Circuit Description

The throttle position (TP) sensor is mounted on the throttle body assembly. The sensor is actually 2 individual TP sensors within one housing. Two separate signal, ground, and 5 volt reference circuits are used to connect the TP sensor assembly and the throttle actuator control (TAC) module. The 2 sensors have opposite functionality. The TP sensor 1 signal voltage increases as the throttle opens, from below 1.0 volt at 0 percent throttle to above 3.5 volts at 100 percent throttle. The TP sensor 2 signal voltage decreases from around 3.8 volt at 0 percent throttle to below 1.0 volt at 100 percent throttle. Also, observe that the signal circuit for TP sensor 1 is pulled up to 5  volts and that the signal circuit for TP sensor 2 is referenced to ground within the TAC module.

Conditions for Running the DTC

    • No active TAC module DTCs
    • The ignition switch in the crank or run position.
    • The ignition voltage is more than 5.23 volts.

Conditions for Setting the DTC

    • The TP sensor 2 voltage is less than 0.13 volts or more than 4.87 volts.
    • All of the above conditions are met for less than 1 second.

Action Taken When the DTC Sets

    • The PCM stores the DTC information into memory when the diagnostic runs and fails.
    • The PCM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or Failure Records.
    • The TAC system operates in reduced engine power mode. If certain TAC system DTCs are set at the same time, the TAC system may command the engine to shut down.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Use a scan tool in order to clear the MIL and the DTC.

Diagnostic Aids

Important: 

   • Remove any debris from the powertrain control module (PCM) or TAC module connector surfaces before servicing the PCM or TAC module. Inspect the PCM or TAC module connector gaskets when diagnosing or replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM or TAC modules.
   • For any test that requires probing the PCM or a component harness connector, use the J 35616 connector test adapter kit . Using this kit prevents damage to the harness or component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

    • The following may cause an intermittent:
       - Poor connections--Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
       - Corrosion
       - Misrouted harness.
       - Rubbed through wire insulation.
       - Broken wire inside the insulation.
    • Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs should be set and no circuit or component conditions can be located.
    • The APP sensor 1 and the TP sensor 1 5  volt reference circuits are internally connected within the TAC module.
    •  The APP sensor 2 and the TP sensor 2 5 volt reference circuits are internally connected within the TAC module.
    • 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. Keep this in mind when reviewing captured DTC info.
    • For an intermittent, refer to Symptoms .

Test Description

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

  1. Disconnect the throttle actuator connector before inserting fingers into the throttle bore. Re-install the air inlet duct after repairs are completed.

  2. The sensor voltage should drop to zero when you disconnect the sensor.

  3. Using a test lamp reduces the amount of current fed into the signal circuit. The scan tool should display the maximum value for this parameter (5.0 volts) even though the actual voltage is higher.

  4. This step is testing for a short to voltage on the TP sensor 2 signal circuit.

  5. This step is testing for a short to voltage on the APP sensor 2 signal circuit.

    The TP sensor 2 and the APP sensor 2 share a common 5.0 volt reference. A short to voltage on the APP sensor 2 signal circuit will affect the 5.0 volt reference circuit.

  6. This step is testing for a short to voltage on the TP sensor 2 5.0 volt reference circuit.

    The TP sensor 2 and the APP sensor 2 share a common 5.0 volt reference. The 5.0 volt reference circuits are connected internally within the TAC module. Disconnecting the TAC module will isolate the 5.0 volt reference circuits.

  7. This step is testing for a short to voltage on the APP sensor 2 5.0 volt reference circuit.

    The TP sensor 2 and the APP sensor 2 share a common 5.0 volt reference. A short to voltage on the APP sensor 2 5.0 volt reference circuit will affect the TP sensor  2 5.0 volt reference circuit.

  8. This step is testing for an open TP sensor 2 5.0 volt reference circuit.

  9. The TP sensor 2 5.0 volt reference circuit is shorted to ground if the DMM indicates continuity.

  10. The APP sensor 2 5.0 volt reference circuit is shorted to ground if the DMM indicates continuity.

  11. When the TAC module detects a problem 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 problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info.

DTC P1220 - Throttle Position (TP) Sensor 2 Circuit

Step

Action

Value(s)

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

Is DTC P1515, P1516, or P1518 also set?

--

Go to the applicable DTC

Go to Step 3

3

  1. Remove the air inlet duct from the throttle body assembly.
  2. Important: Disconnecting the throttle actuator motor connector causes additional DTCs to set.

  3. Disconnect the throttle actuator harness connector.
  4. Close the throttle blade completely by hand while observing the TP sensor 2 voltage on the scan tool.

Is the voltage within the specified range?

4.3-4.8 V

Go to Step 4

Go to Step 7

4

Open the throttle blade to wide open throttle (WOT) by hand while observing the TP sensor 2 voltage on the scan tool.

Is the voltage within the specified range?

0.13-1 V

Go to Step 5

Go to Step 7

5

  1. Reconnect the throttle actuator harness connector.
  2. Turn OFF the ignition for 15 seconds.
  3. Turn ON the ignition, with the engine OFF.
  4. Select the Diagnostic Trouble Code (DTC) Information option using the scan tool.
  5. Move the harness and the related connectors while monitoring the DTC Information.

Does the harness movement cause this DTC to set?

--

Go to Step 24

Go to Step 6

6

  1. Continue to monitor DTC Information using the scan tool.
  2. Slowly depress the accelerator pedal to wide open throttle (WOT) and then slowly release the pedal to close the throttle.

Did this DTC set?

--

Go to Step 28

Go to Diagnostic Aids

7

Monitor the TP sensor 2 voltage using a scan tool.

Is the voltage near the specified value?

5.0 V

Go to Step 8

Go to Step 11

8

Disconnect the TP sensor harness connector.

Does the scan tool indicate the specified voltage for TP sensor  2?

0 V

Go to Step 9

Go to Step 12

9

  1. Turn OFF the ignition.
  2. Measure the resistance from the TP sensor  2 ground circuit in the TP sensor harness connector to the battery ground using the DMM .

Is the resistance within the specified range?

0-5 ohms

Go to Step 10

Go to Step 25

10

  1. Disconnect the APP sensor. Refer to Accelerator Pedal Position Sensor Replacement .
  2. Turn ON the ignition, with the engine OFF.
  3. Probe the TP sensor 2 5.0 volt reference circuit using the DMM connected to battery ground.

Is the voltage near the specified value?

5.0 V

Go to Step 13

Go to Step 17

11

  1. Disconnect the TP sensor harness connector.
  2. Probe the TP sensor  2 signal circuit using the test lamp connected to B+.

Does the scan tool indicate the specified voltage?

5.0 V

Go to Step 19

Go to Step 14

12

  1. Turn OFF the ignition.
  2. Leave the TP sensor disconnected.
  3. Disconnect the TAC module connector containing the TP sensor circuits.
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the voltage from the TP sensor  2 signal circuit in the TP sensor harness connector to the battery ground using the DMM .

Is any voltage present?

0 V

Go to Step 23

Go to Step 16

13

  1. Turn OFF the ignition.
  2. Disconnect the TAC module.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the APP sensor  2 signal circuit at the TAC module harness connector to the battery ground using the DMM .

Is any voltage present?

0 V

Go to Step 23

Go to Step 22

14

  1. Turn OFF the ignition.
  2. Leave the TP sensor disconnected.
  3. Disconnect the TAC module connector containing the TP sensor circuits.
  4. Test the harness for continuity of the TP sensor  2 signal circuit using the DMM .

Does the DMM indicate continuity?

0 ohms

Go to Step 15

Go to Step 25

15

Test the harness for continuity between the TP sensor 2 signal circuit and the battery ground using the DMM .

Does the DMM indicate continuity?

Go to Step 26

Go to Step 16

16

Test the TAC harness for continuity between the TP sensor  2 signal circuit and all other circuits in both TAC module connectors using the DMM .

Does the DMM indicate continuity?

Go to Step 27

Go to Step 30

17

  1. Turn OFF the ignition.
  2. Leave the TP and the APP sensors disconnected.
  3. Disconnect the TAC module connector containing the TP sensor circuits.
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the voltage from the TP sensor  2 5.0 volt reference circuit in the TP sensor harness connector to the battery ground using the DMM .

Is any voltage present?

0 V

Go to Step 23

Go to Step 18

18

  1. Turn OFF the ignition.
  2. Disconnect the other TAC module connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the APP sensor  2 5.0 volt reference circuit at the TAC module harness connector to the battery ground using the DMM .

Is any voltage present?

0 V

Go to Step 23

Go to Step 22

19

  1. Turn OFF the ignition.
  2. Disconnect the TAC module connector containing the TP sensor circuits.
  3. Turn OFF the ignition.
  4. Test the harness continuity for the TP sensor  2 5.0 volt reference circuit using the DMM .

Is the resistance within the specified range?

0-2 ohms

Go to Step 20

Go to Step 25

20

Test the harness for continuity between the TP sensor  2 5.0 volt reference circuit and the battery ground using the DMM .

Does the DMM indicate continuity?

Go to Step 26

Go to Step 21

21

  1. Turn OFF the ignition.
  2. Disconnect the other TAC module connector.
  3. Test the harness for continuity between the APP sensor  2 5.0 volt reference circuit and the battery ground using the DMM .

Does the DMM indicate continuity?

Go to Step 26

Go to Step 22

22

Test the TAC harness for continuity between the TP sensor 2 5.0 volt reference circuit and all other circuits in both TAC module connectors using the DMM .

Does the DMM indicate continuity?

Go to Step 27

Go to Step 28

23

Repair the short to voltage in the circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 32

--

24

Repair the harness and connections as necessary. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 32

--

25

Repair the open and high resistance in the circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 32

--

26

Repair the short to ground in the circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 32

--

27

Repair the circuits that are shorted together. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 32

--

28

  1. Inspect for poor connections and terminal tension at the TP sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. Repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 32

Go to Step 29

29

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

Is the action complete?

--

Go to Step 32

--

30

  1. Inspect for poor connections and terminal tension at the TAC module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. Repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 32

Go to Step 31

31

Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement .

Is the action complete?

--

Go to Step 32

--

32

  1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the scan tool.
  2. Idle the engine at the normal operating temperature.
  3. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

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

--

Go to Step 33

Go to Step 2

33

Select the Capture Info option and the Review Info option using the scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to the applicable DTC table

System OK