For 1990-2009 cars

### Circuit Description

This DTC indicates that a transmission related OBD II failure has occurred. The Transmission Control Module (TCM) controls a dedicated Service Transmission Lamp (STL) which illuminates when a fail reports by certain non-emissions related TCM diagnostics. The TCM has no direct control of the engine MIL, but if a transmission fault occurs that is emissions related, the engine MIL must illuminate. A MIL Request circuit between the ECM and the TCM provides a means for illuminating the MIL, even though the fault was detected by the TCM. This circuit is pulled up to B+ within the ECM. In order to illuminate the MIL, the TCM pulls the circuit low. The ECM detects this and DTC P1700 is set, which illuminates the MIL.

### Conditions for Running the DTC

Tested continuously

### Conditions for Setting the DTC

An OBD II transmission DTC has been stored by the TCM.

### Action Taken When the DTC Sets

• | The ECM illuminates the Malfunction Indicator Lamp (MIL) 1 second after the request from the TCM is received.

• | The ECM records operating conditions at the time the TCM initiates the request. This information will store in the Freeze Frame.

### Conditions for Clearing the MIL/DTC

• | The ECM will turn the MIL off approximately 1 second after the TCM request is no longer received.

• | A History DTC clears after forty consecutive warm-up cycles if no failures report by this diagnostic or any other emission related diagnostic.

• | The ECM battery voltage is interrupted.

• | The scan tool clears the MIL/DTC.

#### DTC P1700 - MIL Requested By TCM

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System check? | -- | Go to Transmission Diagnosis | Go to Powertrain On Board Diagnostic (OBD) System Check