Circuit Description
The stop lamp switch (TAC brake switch) is a normally open switch. When the switch is closed, the TAC module senses ignition voltage on the signal circuit. If the PCM senses a high rate of deceleration without a input from this switch this DTC will set.
Conditions for Running the DTC
| • | The engine speed is more than 1000 RPM. |
| • | The wheel speed must be more than 20 MPH in order to enable the diagnostic. The diagnostic will disable when the wheel speed is less than 5 MPH. |
Conditions for Setting the DTC
| • | The vehicle speed decreases 0.5 MPH in 0.5 seconds without the PCM sensing a switch transition. |
| • | The condition is present for 20 accel/decel cycles. |
Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.
Conditions for Clearing the MIL/DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Diagnostic Aids
In order to adjust the stop lamp switch perform the following:
- With the brake pedal depressed, insert the brake lamp switch into the retainer until the switch body seats in the retainer. You can hear clicks as you push the threaded portion of the switch through the retainer.
- Slowly pull the brake pedal fully rearward against the stop until you can no longer hear the clicks.
Inspect for the following:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 | With a scan tool, observe the TAC brake switch parameter. Does the scan tool indicate Released? | -- | ||
3 | Depress the brake pedal approximately half-way. Does the scan tool indicate Applied? | -- | Go to Diagnostic Aids | |
4 | Test the adjustment of the brake switch. Refer to Diagnostic Aids. Did you find and correct the condition? | -- | ||
5 | Inspect the condition of the fuse. Is the fuse OK? | -- | ||
6 |
Does the test lamp illuminate? | -- | ||
7 |
Does the parameter indicate Applied when the jumper is installed? | -- | ||
8 |
Does the parameter indicate Released when the switch is disconnected? | -- | ||
9 | Test the feed circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
10 | Repair the short to ground in the signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
11 | Repair the open in the feed circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
12 | Test the signal circuit for an open between the switch and the EBTCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
13 |
Does the test lamp illuminate? | -- | ||
14 | Repair the short to voltage on the signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
15 | Inspect for poor connections at brake switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
16 | Replace the brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | -- | -- | |
17 | Test the signal circuit for an open or high resistance between the TAC module and the EBTCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
18 | Inspect for poor connections at the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
19 | Replace the TAC module. Refer to Accelerator Pedal Replacement Did you complete the replacement? | -- | -- | |
20 |
Does the DTC reset? | -- | ||
21 | Does the scan tool indicate any DTCs set that you have not diagnosed? | -- | Go to applicable DTC | System OK |
