Circuit Description
The stop lamp/torque converter clutch (TCC) brake switch/cruise control release switch is used as an input to the transmission control module (TCM) to indicate the status of the brake pedal: applied or released.
The normally closed TCC brake switch contacts supplies an ignition voltage input to the TCM terminal X1-38. Applying the brakes, the switch contacts open, interrupting the voltage supply to the TCM. Releasing the brakes, the contacts close and voltage is applied to TCM terminal X1-38.
When the TCM senses 0 voltage at terminal X1-38, the TCM de-energizes the TCC solenoid valve.
If the TCM detects a closed TCC brake switch circuit (stuck off condition) during decelerations, then DTC P0573 sets, which is a type 'C' DTC.
Conditions for Running the DTC
Ignition voltage is between 8.0-18.0 volts
Engine speed is between 450 and 6,800 RPM for a time greater than 5 seconds.
Conditions for Setting the DTC
The brake switch is detected as off in the time of 6.25 minutes without going on.
Action Taken When the DTC Sets
| • | The TCM does not request the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL). |
| • | 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 P0563 into TCM history. |
| • | When fitted, the TCM inhibits autograde braking. |
Conditions for Clearing the DTC
| • | Tech 2 can clear the DTC. |
| • | The TCM clears the DTC from its memory (history DTC) if the vehicle completes 40 warm-up cycles without a non-emission related DTC occurring. |
| • | The TCC brake switch input indicates ignition voltage for 2 seconds. |
| • | The TCM cancels the DTC default actions when the fault no longer exists and the DTC passes. |
Diagnostic Aids
- Inspect the wiring at the TCM, the brake switch connector and all other circuit connecting points for the following conditions:
- When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
- Inspect the brake switch for proper mounting and operation.
| • | A backed out terminal |
| • | A damaged terminal |
| • | Reduced terminal tension |
| • | A chafed wire |
| • | A broken wire inside the insulation |
| • | Moisture intrusion |
| • | Corrosion |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2 This step isolates the brake switch as the source of setting the DTC.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics For Information on Testing Wiring Faults, refer to Wiring Systems | ||||
1 | Has the Diagnostic System Check - Automatic Transmission been completed? | -- | Go to Step 2 | |
2 |
Is voltage reading above the specified value? | 10 V | Go to Step 3 | Go to Step 4 |
3 | Using a fused jumper wire, connect between connector S220-X1 terminals X1-A, circuit 640 and X1-B, circuit 20 of the brake switch connector. Did the TCC brake switch status on the Tech 2 change from ON to OFF? | -- | Go to Step 7 | Go to Step 6 |
4 | Check circuit 640 for open circuit condition between brake switch connector, terminal X1-B and fuse F5. Was an open circuit condition found? | -- | Repair open in circuit 640 Go to Step 10 | Go to Step 5 |
5 | Check circuit 640 for a short to ground condition between brake switch connector, terminal X1-A and the fuse F5 Was a short to ground condition found? | -- | Repair open in circuit 640 Go to Step 10 | Check for an open in circuit 442 between fuse F5 and fusible link F102. Go to Step 10 |
6 | Check circuit 20 for a short to ground condition between brake switch connector S220, terminal X1-B and the transmission wiring harness TCM connector, terminal X1-39. Was a short to ground condition found? | -- | Repair short to ground in circuit 20. Go to Step 10 | Go to Step 8 |
7 | Replace the brake switch. Refer to Stop Lamp Switch Replacement. Is the replacement complete? | -- | Go to Step 10 | -- |
8 | Check circuit 20 for open circuit condition between brake switch connector S220, terminal X1-B and the transmission wiring harness TCM connector, terminal X1-38. Was an open circuit condition found? | -- | Repair open in circuit 20. Go to Step 10 | Go to Step 9 |
9 | Replace the TCM. Refer to Transmission Control Module Replacement. Is the replacement complete? | -- | Go to Step 10 | -- |
10 | Perform the following procedure to verify the repair:
Has the test run and passed? | -- | System OK | Go to Step 2 |
When all diagnosis and repairs are completed, clear all DTCs and verify correct operation. | ||||
