DTC C1291 Open Brake Lamp Switch Contacts During Deceleration. Chevrolet Lumina 2000

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2000 🢒 Lumina 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1291 Open Brake Lamp Switch Contacts During Deceleration

ABS Components
Antilock Brake System Schematics
Power Distribution Schematics
Exterior Lights Schematics
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

DTC C1291 detects an open brake switch in the non-ABS mode. The EBCM looks for deceleration rates that may indicate braking action. The EBCM verifies braking action by repeating the method for finding deceleration rates that indicate braking action several times. In each case, the ABS will not be available because the EBCM does not see the brake switch input.

Conditions for Setting the DTC

DTC C1291 can set if three deceleration cycles within the specified rate occur during the current ignition cycle with the brake switch off.

Action Taken When the DTC Sets

•	A malfunction DTC stores.

•	The ABS disables.

•	The amber ABS warning indicators turns on.

Conditions for Clearing the DTC

•	The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.

•	100 drive cycles pass with no DTCs detected.

Diagnostic Aids

The following conditions may cause an intermittent malfunction:

•	A poor connection

•	Rubbed-through wire insulation

•	A broken wire inside the insulation

•	Brake switch adjustment

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Refer to the Scan Tool manual or Scan Tool Diagnostics located in this section for the procedure.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

•	Backed out terminals

•	Improper mating

•	Improperly formed or damaged terminals

•	Poor terminal-to-wiring connections

•	Physical damage to the wiring harness

Important: Zero the J 39200 test leads before making any resistance measurements.

Step

Action

Value(s)

Yes

Was the Diagnostic System Check performed?

Go to Step 2

Go to Diagnostic System Check - ABS

Turn the ignition switch to the ON position.

Do not start the engine.

Install a scan tool.
Use the scan tool in order to inspect for DTCs.

Is DTC C1295 set as either a current and/or history DTC?

Go to DTC C1293 DTC C1291/C1292 Set in Current or Previous Ignition Cycle

Go to Step 3

Select Data List on the scan tool.
Select Brake Switch Position on the scan tool.
Apply light pressure to the brake pedal while monitoring the Brake Switch Position on the scan tool.

Does the scan tool indicate that the brake switch is ON within 25 mm (1.0 inch) of brake pedal travel?

Go to Step 23

Go to Step 4

Apply firm pressure to the brake pedal.
Observe the rear brake lamps.

Are the rear brake lamps on?

Go to Step 5

Go to Step 8

Turn the ignition switch to the OFF position.
Disconnect the 24-way EBCM connector C1.
Turn the ignition switch to the ON position.

Do not start the engine.

Apply firm pressure to the brake pedal.
Use the J 39200 in order to measure the voltage between the 24-way EBCM harness connector C1 terminal B9 and ground.

Is the voltage equal to or greater than the specified voltage?

10.0 V

Go to Step 6

Go to Step 14

Inspect the 24-way EBCM connector C1 and the 24-way EBCM harness connector C1 for the following conditions:

•	Terminal damage

•	Poor terminal contact

•	Terminal corrosion

Is there poor terminal contact, terminal corrosion, or damaged terminals?

Go to Step 15

Go to Step 7

Reconnect the 24-way ECM connector C1.
Test drive the vehicle and perform a brake stop from 32 km/h (20 mph) while engaging the ABS.
Use the scan tool in order to inspect for DTCs.

Does DTC C1291 or DTC C1292 set as a current DTC?

Go to Step 21

Go to Step 23

Use the J 39200 in order to measure the voltage between the stoplamp switch harness connector C1 terminal A and ground.

Is the voltage equal to or greater than the specified voltage?

10.0 V

Go to Step 9

Go to Step 11

Apply firm pressure to the brake pedal.
Use the J 39200 in order to measure the voltage between the stoplamp switch harness connector C1 terminal B and ground.

Is the voltage equal to or greater than the specified voltage?

10.0 V

Go to Step 14

Go to Step 10

Inspect for proper adjustment of the stoplamp switch.

Is the stoplamp switch adjusted correctly?

Go to Step 16

Go to Step 17

Use the J 39200 in order to measure the voltage between both sides of Fuse 23 (15A).

Is the voltage within the specified range?

10.0-14.5 V

Go to Step 19

Go to Step 12

Disconnect the 24-way EBCM connector C1.
Use the J 39200 in order to measure the resistance between the 24-way EBCM connector C1 terminal B9 and ground.

Is the resistance within the specified range?

(Infinite)

Go to Step 13

Go to Step 18

Disconnect the stoplamp switch connector C1.
Use the J 39200 in order to measure the resistance between the stoplamp switch harness connector C1 terminal A and ground.

Is the resistance within the specified range?

(Infinite)

Go to Step 22

Go to Step 20

Repair the open in CKT 17.

Is the repair complete?

Go to Diagnostic System Check - ABS

Replace all the terminal or the connectors that exhibit the following conditions: