GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The throttle position (TP) sensors 1 and 2 are located within the throttle body assembly. The TP sensors share a common 5-volt reference circuit and a common low reference circuit. The 5-volt reference circuit is also shared with accelerator pedal position (APP) sensor 2. The 5-volt reference voltage is supplied on 2 separate engine control module (ECM) terminals, but the terminals are connected internally to the same voltage supply. Each TP sensor has an individual signal circuit, which provides the ECM with a signal voltage proportional to the throttle plate movement. When the throttle plate is in the closed position, the TP sensor 1 signal voltage is near the low reference and increases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. IF the ECM detects the TP sensor 1 signal voltage is more than 4.89 volts, DTC P0223 sets.

Conditions for Running the DTC

    • The battery voltage is more than 10 volts.
    • The ignition is ON.

Conditions for Setting the DTC

The TP sensor 1 voltage is more than 4.89 volts for more than 60 milliseconds.

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.

Step

Action

Value

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the throttle position (TP) sensor 1 parameter with a scan tool.

Is the TP sensor 1 voltage more than the specified value?

4.6 V

Go to Step 3

Go to Step 4

3

  1. Turn OFF the ignition.
  2. Disconnect the throttle body harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the TP sensor 1 parameter with a scan tool.

Is the TP sensor 1 voltage less than the specified value?

0.2 V

Go to Step 6

Go to Step 13

4

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze/Frame Failure Records.

Did the DTC fail this ignition?

--

Go to Step 6

Go to Step 5

5

  1. Observe the DTC Information with a scan tool.
  2. Slowly depress the accelerator pedal to wide-open throttle (WOT) and then slowly return it to the closed position.
  3. Repeat this action several times.

Did the DTC fail this ignition?

--

Go to Step 19

Go to Intermittent Conditions

6

  1. Turn OFF the ignition.
  2. Disconnect the throttle body harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the 5-volt reference circuit of the TP sensors to a good ground with a DMM.

Is the voltage within the specified range?

4.8-5.2 V

Go to Step 7

Go to Step 11

7

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the TP sensor and the signal circuit of the TP sensor 1.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the TP sensor 1 parameter with a scan tool.

Is the voltage within the specified range?

4.8-5.2 V

Go to Step 8

Go to Step 13

8

  1. Turn OFF the ignition for 30 seconds.
  2. Allow the engine control module (ECM) to completely power down. This can be verified by the loss of communication on the scan tool.
  3. Measure the resistance from the low reference circuit of the TP sensors to a good ground with the DMM.

Is the resistance less than the specified value?

5 ohms

Go to Step 15

Go to Step 9

9

  1. Disconnect the ECM.
  2. Test the low reference circuit of the TP sensors for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 10

10

Measure the resistance from the case of the ECM to battery ground.

Is the resistance less than the specified value?

5 ohms

Go to Step 17

Go to Step 18

11

  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal position (APP) sensor harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the 5-volt reference circuit of the TP sensors to a good ground with the DMM.

Is the voltage within the specified range?

4.8-5.2 V

Go to Step 16

Go to Step 12

12

Test the 5-volt reference circuit of the TP sensor 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 21

Go to Step 14

13

Test the signal circuit of the TP sensor 1 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 21

Go to Step 17

14

Test the 5-volt reference circuit of the APP sensor 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 21

Go to Step 17

15

Test for an intermittent and for a poor connection at the throttle body sensor. 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 21

Go to Step 19

16

Test the signal circuit of APP sensor 2 for short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 17

17

Test for shorted terminals and poor connections at the ECM. 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 21

Go to Step 20

18

Repair the open or high resistance in the ECM ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 21

--

19

Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .

Did you complete the replacement?

--

Go to Step 21

--

20

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 21

--

21

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze/Frame Failure Records.

Did the DTC fail this ignition?

--

Go to Step 2

Go to Step 22

22

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

System OK