Circuit Description
The Stop Lamp Switch is normally closed. With the ignition in the RUN position and the brake pedal not depressed, the EBCM will have ignition voltage present at terminal C of the 10-way connector. When the brakes are applied, the ignition voltage present at the EBCM will be zero.
Conditions for Setting the DTC
| • | The vehicle is above 15 mph |
| • | The Stop Lamp Switch never switches during the condition above |
Action Taken When the DTC Sets
| • | DTC C0081 is advisory code only |
| • | The ABS indicator lamp will not be illuminated |
| • | The ABS will not be disabled |
DTC C0081 is an Ignition Latched DTC, which indicates that the above actions remain true until the ignition is turned to OFF (even if the cause of the DTC is intermittent).
Conditions for Clearing the DTC
| • | Repair the conditions responsible for setting the DTC |
| • | Use the Scan Tool Clear DTCs function |
Diagnostic Aids
DTC C0081 can be set by a faulty Stop Lamp Switch, misadjusted Stop Lamp Switch or damage in CKT 420 or CKT 441.
Thoroughly check any circuitry that is suspected of causing the intermittent complaint for the following conditions:
| • | Backed out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal to wiring connections |
| • | Physical damage to the wiring harness |
Test Description
The numbers below refer to the steps in the diagnostic table:
-
This step checks the functionality of the Stop Lamp Switch circuit using the Scan Tool .
-
This step checks for a short to voltage in the Stop Lamp Switch circuit between the Stoplamp Switch and the EBCM.
-
This step checks the functionality of the Stop Lamp Switch circuit using the Scan Tool .
-
This step checks for an open in the Stop Lamp Switch circuit between the Stoplamp Switch and the EBCM.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |||||||
Does the scan tool indicate that the Stop Lamp Switch to be closed constantly? | -- | |||||||||
Does the scan tool indicate that the Stop Lamp Switch to be closed? | -- | |||||||||
Does the scan tool indicate that the Stop Lamp Switch to be open constantly? | -- | |||||||||
Is the voltage measured equal to or greater than the specified range? | 10.0 V | |||||||||
6 |
Does the scan tool indicate that the Stop Lamp Switch to be open constantly while applying and releasing the brake pedal. | -- | ||||||||
7 | Malfunction is intermittent. Refer to Diagnostic Aids. Repair all damage found. Is repair compete? | -- | Go to Diagnostic System Check | -- | ||||||
8 |
Is repair complete? | -- | Go to Diagnostic System Check | -- | ||||||
9 | Replace the EBCM. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||
10 | Repair the short to voltage in CKT 420. Is the repair complete? | -- | Go to Diagnostic System Check | -- | ||||||
11 | Check for the following:
Is repair complete? | -- | Go to Diagnostic System Check | -- |
