Circuit Description
The stop lamp switch is a normally open switch. The Inverting Driver Module inverts the brake switch signal to make the normally open brake switch compatible with the EBCM. With the ignition in the RUN position and the brake pedal not depressed, the EBCM will have ignition voltage present. With the brakes applied, the ignition voltage present at the EBCM will be zero.
Conditions for Setting the DTC
| • | Vehicle above 56 km/h (35 mph) for 10 seconds, followed by vehicle at rest for 1 second. |
| • | Stop lamp never switching during the above condition |
Action Taken When the DTC Sets
| • | The ABS indicator lamp will be illuminated |
| • | The ABS will be disabled |
DTC C0281 is a ignition latched DTC which indicates the above is true until the ignition is turned to OFF (even if the cause 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 C0281 can be set by a faulty Stop Lamp Switch, faulty Inverting Driver Module or damage in the following circuits: CKT 145, CKT 470, CKT 471, CKT 652 CKT 653, CKT 654, CKT 848.
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:
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This step checks the functionality of the Stop Lamp Switch circuit using the Scan Tool .
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This step checks the functionality of the Stop Lamp Switch circuit (including the Inverter Driving Module) using a J 39200 .
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This step checks the functionality of the Stop Lamp Switch circuit up to the Inverting Driving Module.
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This step checks for a short to ground in the Stop Lamp Switch circuit between the Inverting Driver Module and the EBCM.
-
This step checks the resistance in the ground circuit to the Inverting Driver Module.
-
This step checks the ignition voltage at the Inverting Driver Module.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check |
Does the scan tool indicate that the Stop Lamp Switch is opening and closing? | -- | Go to Step 11 | Go to Step 3 | |
Is the voltage measured switching between the specified range? | 0-12 V | Go to Step 11 | Go to Step 4 | |
Is the voltage equal to or greater than the specified range? | 10 V | Go to Step 7 | Go to Step 5 | |
5 |
| 10 V | Go to Step 6 | Go to Step 12 |
6 | Using a J 39200 , measure the resistance between terminal A of the brake switch harness connector and terminal C of the Inverting Driver Module. Is the resistance measured within the specified range? | 0-2 ohms | Go to Diagnostic Aids | Go to Step 13 |
7 | Using a J 39200 , measure the resistance between terminal A of the Inverting Driver Module harness connector and terminal 15 of the 24-way EBCM harness connector. Is the resistance measured within the specified range? | 0-2 ohms | Go to Step 8 | Go to Step 15 |
Using a J 39200 , measure the resistance between terminal A of the Inverting Driver Module harness connector and ground. Is the resistance measured within the specified range? | OL | Go to Step 9 | Go to Step 18 | |
Using a J 39200 , measure the resistance between terminal D of the Inverting Driver Module harness connector and ground. Is the resistance measured within the specified range? | 0-2 ohms | Go to Step 10 | Go to Step 16 | |
Using a J 39200 , measure the voltage between terminal B of the Inverting Driver Module harness connector and ground. Is the voltage measured within the specified range? | 10 V | Go to Diagnostic Aids | Go to Step 17 | |
11 |
Does DTC C0281 set as a current DTC? | -- | Go to Step 19 | Go to Diagnostic Aids |
12 | Repair open in CKT 470. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
13 | Repair open in CKT 653. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
14 | Repair misadjusted or faulty brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
15 | Repair open in CKT 848. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
16 | Repair open in CKT 652. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
17 | Repair open in CKT 654 or CKT 145. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
18 | Repair short to ground in CKT 848.Refer to Wiring Repairs . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
19 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | -- |
