This diagnostic procedure supports DTC P0724 Brake Switch Circuit Low Voltage.
The transmission control module receives a direct input from the stop lamp switch assembly. When the brake pedal is pressed, 12V is supplied to the TCM through connector A112-X1 pin 42.
When the TCM detects an open or short to ground on the stop lamp signal circuit during stopping then DTC P0724 sets. DTC P0724 is a type C DTC.
Refer to Automatic Transmission Controls Schematics , Automatic Transmission Inline 20-Way Connector End View , Automatic Transmission Internal Connector End Views , Automatic Transmission Control Module Connector End Views , and Automatic Transmission Related Connector End Views to aid in diagnosis. to aid in diagnosis.
• | No DTCs P0719, P0722 or P0723. |
• | The vehicle speed is greater than 40 km/h for 7 seconds, then 8-40 km/h for 5 seconds, then less than 8 km/h. |
• | Continuously eight times once the previous criteria have been met. |
The TCM detects an open or short to ground on the stop lamp switch signal circuit when the circuit should be high, battery voltage.
• | The TCM does not request the engine control module (ECM) to illuminate the check powertrain icon. |
• | The TCM records the operating conditions when the conditions for setting the DTC are met. The TCM records this information as a Failure Record. |
• | The TCM stores DTC P0724 in TCM history. |
• | The TCM clears the DTC from TCM history if the vehicle complete 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
• | Tech 2 can clear the DTC. |
• | Verify the brake pedal position sensor is adjusted properly, refer to Stop Lamp Switch Testing. |
• | Test drive the vehicle if a switch or circuit condition cannot be located. An intermittent condition may be duplicated during a test drive. |
The following numbers refer to the step numbers in the diagnostic table:
3 Checks if the stop lamp switch is serviceable.
4 Checks if there is a stop lamp switch signal to the TCM.
Step | Action | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|
1 | Has the Diagnostic System Check been performed? | Go to Step 2 | |||||||
2 |
Does the Stop Lamp Pedal Switch parameter indicate Active? | Check for an intermittent fault in the circuit, refer to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | ||||||
3 | Test the stop lamp switch assembly, refer to Stop Lamp Switch Testing. Is the stop lamp switch assembly serviceable? | Go to Step 4 | Replace the stop lamp switch assembly. Refer to Stop Lamp Switch Replacement | ||||||
4 |
Does the multimeter display battery voltage? | Go to Step 5 | Repair or replace circuit 20 Go to Step 6 | ||||||
5 | Replace the TCM, refer to Transmission Control Module Replacement. Did you complete the replacement? | Go to Step 6 | -- | ||||||
6 | Perform the following procedure in order to verify the repair:
Has DTC P0724 set? | Go to Step 2 | Go to Step 7 | ||||||
7 | On Tech 2 select: Diagnostic Trouble Codes/Read DTC Information. Does Tech 2 display any DTCs you have not diagnosed? | System OK | |||||||
When all diagnosis and repairs are completed, check the system for correct operation. |