GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The throttle body assembly contains the following components:

    • The throttle blade
    • The throttle actuator motor
    • The throttle position (TP) sensor 1 and TP sensor 2
    • The throttle actuator control (TAC) module

The TAC system monitors the throttle position with 2 sensors. If the powertrain control module (PCM) receives a message from the TAC module that the throttle position, as indicated from TP sensor 1, disagrees with the throttle position indicated from TP sensor 2, DTC P2135 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2135 Throttle Position (TP) Sensor 1-2 Correlation

Conditions for Running the DTC

    • DTC P0606, P2108, U0107 are not set.
    • The ignition switch is in the Crank or Run position.
    • The ignition voltage is more than 5.23 volts.
    • The communication between the TAC module and the PCM must be valid.

Conditions for Setting the DTC

    • The throttle position indicated by TP sensor 1 disagrees with the throttle position indicated by TP sensor 2 by more than 6 percent.
        OR
    • The PCM learned minimum throttle position of TP sensor 1 disagrees with the learned minimum throttle position of TP sensor 2.
        OR
    • The PCM detects that the TP sensor 1 signal circuit is shorted to the TP sensor 2 signal circuit.

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

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views and 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

Are any other DTCs set?

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

Go to Step 3

3

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

Did you complete the replacement?

Go to Step 4

--

4

  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 5

5

Important: Be aware that repairing 1 individual condition may correct more than 1 DTC.

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