For 1990-2009 cars
ABS Components
Cell 44: PWR, GND, and Stoplamp/BTSI Switch
Handling ESD Sensitive Parts Notice
Cell 10: MISC LGT, COOL FNS, C/LTR/RDO/CLSTR/MISC, IGN SW, RR DEFOG/PWRSEAT, ABS SOL, and ABS MOT Fuses
Cell 10: BRK/HZRD LPS, FOG LPS, CTSY LP/PWR MIR, and PARKLPS/INT LPS Fuses

### Circuit Description

This circuit detects an open stoplamp/BTSI switch in the non-ABS mode. The EBCM/EBTCM looks for a deceleration rate that indicates braking action and requires several repeats of this detection method in order to verify this assumption. In each case, the TCS will not be available since the EBCM/EBTCM detects no stoplamp/BTSI switch voltage.

### Conditions for Setting the DTC

The stoplamp switch remains open for 3 deceleration cycles.

### Action Taken When the DTC Sets

• | A malfunction DTC is stored.

• | The TCS is disabled.

• | The TRACTION OFF indicator is turned ON.

• | The ABS remains functional.

### Conditions for Clearing the DTC

• | The condition for the DTC is no longer present and you used the scan tool Clear DTC function.

• | The EBCM/EBTCM does not detect the DTC in 50 drive cycles.

### Diagnostic Aids

• | If any wheel speed sensor DTCs are present, diagnose them first. Refer to Diagnostic Trouble Code (DTC) List .

• | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.

• | An intermittent can be caused by a poor connection, broken insulation, or a wire that is broken inside the insulation.

• | If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

• | This DTC may be cause by one of the following:

- | An open stoplamp/BTSI switch.

- | An open brake fuse.

- | A misadjusted stoplamp/BTSI switch.

- | Erratic wheel speeds.

- | A wiring problem, terminal corrosion, or a poor connection in the circuit.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step checks if the stoplamp switch and power distribution are OK.

2. This step checks for voltage at the EBTCM.

3. This step checks the stoplamp switch.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 | Are any wheel speed sensor DTCs present? | -- | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3
3 | Press the brake pedal. Do the brake lights illuminate? | -- | Go to Step 4 | Go to Step 7
4 |

1. Turn OFF the ignition.
2. Disconnect the EBTCM.
3. Install the J 39700 universal pinout box using the J 39700-25 cable adapter to the EBCM/EBTCM harness connector only.
4. Turn ON the ignition leaving the engine OFF.
5. Using the J 39200 DMM in order to measure the voltage at the J 39700 terminal 3 while an assistant presses the brake pedal.

Is the voltage within the specified range?

Battery Voltage

Go to Step 5

Go to Step 6

5 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | Go to Diagnostic System Check - ABS | --
6 | Repair the open or high resistance in CKT 17 (WHT) or CKT 20 (LT BLU). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check - ABS | --
7 | Inspect the BRK/HZRD LPS fuse in the IP fuse block. Is the fuse OK? | -- | Go to Step 8 | Go to Step 12
8 |

1. Disconnect the stoplamp/BTSI switch connector.
2. Use the J 39200 DMM in order to measure the voltage at the stoplamp/BTSI switch harness connector terminal A.

Is the voltage within the specified range?

Battery voltage

Go to Step 10

Go to Step 9

9 | Repair the open in CKT 140 (ORN). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check - ABS | --
10 | Connect a fused jumper wire between the stoplamp/BTSI switch harness connector terminal A and terminal B. Do the brake lamps illuminate? | -- | Go to Step 11 | Go to Step 6
11 | Adjust or repair the stoplamp/BTSI switch as needed. Refer to Stop Lamp Switch Adjustment or Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the repair? | -- | Go to Diagnostic System Check - ABS | --
12 |

1. Replace the BRK/HZRD LPS fuse. Do not press the brake pedal.
2. Inspect the BRAKE fuse.

Is the fuse OK?

--

Go to Step 14

Go to Step 13

13 | Repair the short to ground in CKT 140 (ORN). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check - ABS | --
14 |

1. Press the brake pedal.
2. Inspect the BRK/HZRD LPS fuse.

Is the fuse OK?

--

Go to Diagnostic System Check - ABS

Go to Step 15

15 |

1. Turn OFF the ignition.
2. Disconnect the EBCM/EBTCM.
3. Replace the fuse.
4. Turn ON the ignition leaving the engine OFF.
5. Press the brake pedal.
6. Inspect the BRAKE fuse.

Is the fuse OK?

--

Go to Step 5

Go to Step 16

16 | Repair the short to ground in CKT 17 (WHT) or CKT 20 (LT BLU). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check - ABS | --