GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit , a common low reference circuit, and 2 independent signal circuits.

The TP sensors have opposite functionality . TP sensor 1 signal voltage decreases from above 4 volts at idle to below 1 volt at wide open throttle (WOT). TP sensor 2 signal voltage increases from below 1 volt at idle to above 4 volts at WOT.

If the ECM detects TP sensor 2 signal voltage is too high, this DTC will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0223 Throttle Position (TP) Sensor 2 Circuit High Voltage

Conditions for Running the DTC

    • The ignition is ON, with the engine OFF, or the engine is operating.
    • The ignition 1 voltage is more than 5.23 volts.
    • DTC P0223 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects the TP sensor 2 signal voltage is more than 4.65 volts 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

    • Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
    • If there is a condition with the TP sensors, the ECM defaults to reduced power mode for the entire ignition cycle, even if the condition is corrected.
    • For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .

Step

Action

Values

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

2

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

Is the voltage more than the specified value?

4.65 V

Go to Step 4

Go to Step 3

3

  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 4

Go to Diagnostic Aids

4

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

Does the DMM indicate voltage within the specified range?

4.8-5.2 V

Go to Step 5

Go to Step 10

5

Probe the TP sensor signal circuit with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 6

6

Observe the TP Sensor 2 parameter with a test lamp still connected to the TP sensor signal circuit.

Does the scan tool indicate voltage at the specified value?

0 V

Go to Step 9

Go to Step 7

7

Test the TP sensor 2 signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

8

Test the signal 2 circuit of the TP sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 16

Go to Step 12

9

Test the TP sensor 2 low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 16

Go to Step 12

10

Test the TP sensor 2 5-volt reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 16

Go to Step 11

11

Test for shorted terminals and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

12

Test for an intermittent and for a poor connection at the throttle body harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

13

Test for an intermittent and for a poor connection at the ECM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

14

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

Did you complete the replacement?

--

Go to Step 16

--

15

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 16

--

16

  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 17

17

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

System OK