GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2004 🢒 ION 🢒 DTC 🢒 DTC P0703

Circuit Description

Brake switch information is sent to the transmission control module (TCM) by the engine control module (ECM) through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the ECM and TCM. A fault in the CAN will not cause DTC P0703 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P0703.

When the ECM sends the TCM an invalid brake switch signal, then DTC P0703 will set. DTC P0703 is a type C DTC.

Conditions for Running the DTC
    • No CAN DTC U2105.
    • Trans. Protection Mode OFF.
    • The ignition has been ON for at least 3.0 seconds.

Conditions for Setting the DTC

The brake switch signal is invalid for 4.0 seconds.

Action Taken When the DTC Sets
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
    • The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame.
    • The TCM stores DTC P0703 in TCM history.

Conditions for Clearing the DIC/DTC
    • The TCM clears the SERVICE VEHICLE driver information center (DIC) message request, when the condition no longer exists.
    • A scan tool can clear the DIC/DTC.
    • The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
    • The TCM cancels the default actions when the ignition is OFF long enough in order to power down the TCM.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.2L (L61)

2
  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.

    3. Important: 

       • Before clearing the DTC, use the scan tool in order to record the ECM Freeze Frame and the TCM Failure Records. Using the Clear Eng./Trans. DTC Info function erases the Freeze Frame and Failure Records from the ECM and the TCM.
       • Using the Clear Eng./Trans. DTC Info function erases stored DTCs in both the ECM and TCM.

  3. Record the DTC Failure Records.

Did you record any ECM Failure Records?

Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 2.2L (L61)

Go to Step 3

3
  1. Clear the DTC.
  2. Turn the ignition OFF for at least 30 seconds.
  3. Start, and allow the engine to idle.

Did DTC P0703 reset?

Go to Step 4

Go to Intermittent Conditions in Engine Controls - 2.2L (L61)

4

Did any other DTCs set?

Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 2.2L (L61)

Go to Step 5

5

Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls - 2.2L (L61).

Is the action complete?

Go to Step 6

--

6

Perform the following operation to verify the repair:

  1. Select DTC on the scan tool.
  2. Select Clear Info.
  3. Start the engine and vary the throttle.
  4. Select Specific DTC.
  5. Enter DTC P0703.

Has the test ran and passed?

Go to Step 7

Go to Step 2

7

With the scan tool, observe the stored information, capture info and DTC info.

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

Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 2.2L (L61)

System OK