Circuit Description
The transmission control module (TCM) communicates the park/neutral switch status to the body control module (BCM) via serial data. The BCM uses this data to control the Electronic PRNDL display on the shifter. The BCM controls the LEDs in the PRNDL display through 4 control circuits.
DTC Descriptor
This diagnostic procedure supports the following DTCs:
| • | DTC B0728 Transmission Range Indicator Circuit A High |
| • | DTC B0733 Transmission Range Indicator Circuit B High |
| • | DTC B0738 Transmission Range Indicator Circuit C High |
| • | DTC B0748 Transmission Range Indicator Circuit P High |
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The ignition voltage is greater than 8.5 volts but less than 17 volts. |
Conditions for Setting the DTC
| • | The BCM detects that the commanded state of the driver and the actual state of the control circuit do not match. |
| • | The condition must be present for a minimum of 115 milliseconds. |
| • | DTC B1327 and DTC B1328 are not set. |
Action Taken When the DTC Sets
| • | The BCM stores the DTC information in memory. |
| • | The BCM disables all PRNDL display outputs. |
Conditions for Clearing the DTC
| • | The history DTC clears after 100 malfunction free warm-up cycles. |
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
An open or short to ground in the instrument panel (I/P) lamps dimmer switch signal can disable the PRNDL display. Check for DTC B2627 in Lighting Systems.
Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Body Control System Schematics and Automatic Transmission Controls Schematics Connector End View Reference: Computer/Integrating Systems 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 |
Does the voltage measure within the specified range? | 9-17 Volts | Go to Step 8 | Go to Step 3 | ||||||||
3 |
Does the scan tool display LOW? | -- | Go to Step 4 | Go to Step 5 | ||||||||
4 | Inspect for poor connections at the harness connector of the shift indicator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 | ||||||||
5 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6 | ||||||||
6 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||||
7 | Replace the shift indicator. Refer to Automatic Transmission Control Indicator Replacement in Automatic Transaxle - AF33-5. Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||||
8 | Repair the short to voltage in the suspect shift indicator signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 9 | -- | ||||||||
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||||||
