For 1990-2009 cars

### Description

The Transmission OBD System Check is an organized approach to identifying a condition created by an electronic transmission control system. You must use the Transmission OBD System Check in conjunction with the Powertrain OBD System Check when an emission related condition occurs, but you may use the Transmission OBD System Check independently for non-emission related conditions. Together, they form the starting point for any driveability complaint diagnosis and direct the service technician to the next logical step in diagnosing the complaint. Understanding and using the table correctly will reduce diagnostic time and prevent the replacement of good parts.

Do not perform this check if a driveability complaint is not present.

### Diagnostic Aids

Inspect all of the related wiring and connections including the connections at the TCM, as these may cause an intermittent concern. Inspect the terminals for any damage or any corrosion. Inspect the connector for any pushed out terminals.

### Test Description

The number(s) below refer to the step numbers on the diagnostic table.

1. Do not perform the Transmission OBD System Check unless one of the concerns noted is present. Failure to follow this procedure could lead to misdiagnosis of the system.

2. The diagnostic tables in this section are, by design, for use with a Scan Tool . If the Scan Tool is inoperative, you must correct this before beginning any other diagnostic procedures. Do not clear the DTCs unless instructed by a diagnostic procedure.

3. Check for applicable service bulletins before proceeding with the diagnosis.

4. If any multiple DTCs are stored, diagnose the DTCs in the following order of priority:

1. | The ECM DTCs.

2. | The System Voltage DTCs.

3. | Component level DTCs (Sensors, Solenoids, Relays etc.). Diagnose the multiple DTCs within this category in numerical order starting with the lowest DTC number.

4. | The System level DTCs (Misfire, Fuel Trim, etc.).

5. | The Transmission DTCs. Refer to Diagnostic Trouble Code Identification for transmission diagnostics.

When there is a known exception, a DTC table may direct the technician to diagnose a different DTC first.

1. Capturing the stored Information will preserve the data that will be lost upon instruction to clear the DTCs at the end of a diagnostic table, or if a TCM disconnect or replacement occurs during a diagnostic procedure. Write down any non-emissions DTCs that are set at this time. Review the captured Information at the end of the diagnostic table in order to catch the next DTC in the event that the multiple DTCs were stored. Follow the order of priority as listed above.

2. Compare the actual control system data with the values in the Scan Tool Data List in order to determine if any parameter is not within limits. Keep in mind that a base engine condition (i.e. advanced cam timing) may substantially alter the sensor values. If the actual data does not correspond with the values in the Typical Scan Tool Data Values table, but the corresponding DTC is not set, this indicates that you have to meet specific conditions before some diagnostics will run. This information is in the supporting text for the DTC table. If you suspect a system fault (Shift Solenoid operation, TCC operation, etc.), refer to the DTCs that apply to that system. The DTC tables are not, by design, for use unless a DTC is set; however, many tables begin with a functional test of the related component. This information can be a useful aid in diagnosis.

#### Transmission On-Board Diagnostic System Check

Step | Action | Value | Yes | No
--- | --- | --- | --- | ---
1 | Inspect for one or more of the following conditions:

• | The malfunction indicator lamp (MIL) illuminates with the engine running

• | The sport mode lamp flashes with the engine running

• | A customer concern of powertrain performance/drivability

• | A suspected fault in a powertrain controlled component or system

Is one or more of the conditions present?

--

Go to Step 2

System OK

2 |

1. Turn the ignition switch to the OFF position.
2. Install the Scan Tool .
3. Turn the ignition switch to the RUN position with the engine OFF.

Does the Scan Tool display data?

--

Go to Step 3

Go to Scan Tool Data List

3 |

1. Select Engine Output Controls on the Scan Tool .
2. Using the Scan Tool , command the MIL ON and OFF.

Does the MIL turn ON and OFF when commanded?

--

Go to Step 4

Go to DTC P0650 Malfunction Indicator Lamp (MIL) Control Circuit

4 | Using the Scan Tool , command the sport mode lamp ON and OFF. Does the sport mode lamp turn ON and OFF when commanded? | -- | Go to Step 5 | Go to Sport Mode Switch/Indicator Always On or Inoperative
5 | Inspect for bulletins which may address any powertrain performance/drivability concerns. Was a bulletin repair made? | -- | Verify the repair | Go to Step 6
6 | Using the Scan Tool , inspect for DTCs which may be set. Are there any DTCs displayed? | -- | Go to Step 7 | Go to Step 8
7 | Use the Scan Tool in order to record any Freeze Frame and Failure Records. Is the action complete? | -- | Go to the applicable DTC table | --
8 | Using the Scan Tool compare the transmission data with the values shown in the Scan Tool Data List list. Are the displayed values normal or within typical ranges? | -- | System OK | Go to Functional Test