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 each TP sensor with a 5-volt reference circuit, a low reference circuit, and a signal circuit.

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 low or too high, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0220 Throttle Position (TP) Sensor 2 Circuit

Conditions for Running the DTC

    • DTCs P0341, P0351, P0601, P0602, P0603, P0604, P0606, P0607 are not set.
    • The ignition is ON, with the engine OFF, or the engine is operating.
    • The ignition 1 voltage is more than 5.23 volts.
    • DTC P0220 runs continuously when the above conditions are met.

Conditions for Setting the DTC

    • The ECM detects the TP sensor 2 signal voltage is less than 0.275 volt for less than one second.
    • The ECM detects the TP sensor 2 signal voltage is more than 4.73 volts for less than one 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 Intermittent Conditions.

Test Description

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

  1. This step verifies that other DTCs are set.

Step

Action

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

Are any other DTCs set?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to DTC P0121