For 1990-2009 cars

### Circuit Description

The EBTCM monitors the following occurrences in order to calculate the brake rotor temperatures:

• | Vehicle speed deceleration

• | The ABS/TCS activation

• | The brake lamp on times

When the brake rotor temperatures are exceeded, the following events occur:

• | The TCS is disabled

• | A DTC C1238 is set

• | The TRACTION OFF indicator is turned on

If the brake usage is reduced during driving, the brake rotor cooling is calculated and the TCS is enabled.

### Conditions for Setting the DTC

DTC C1238 could be set when either driven wheel estimated brake rotor temperature exceeds 375°C (700°F). If either driven wheel estimated brake rotor temperature has exceeded 375°C (700°F) during ABS or normal braking conditions, the code will not be set until the next TCS activation occurs. The code will not be set and TCS will not be disabled if both rotor estimated temperatures have cooled below 275°C (530°F) before the next TCS activation. If either driven wheel brake rotor temperatures has exceeded 375°C (700°F) during TCS then the code will be set immediately, but TCS will not be disabled until the end of the TCS event.

### Action Taken When the DTC Sets

• | A DTC C1238 is stored

• | The TCS is disabled

• | The TRACTION OFF indicator is turned on

### Conditions for Clearing the DTC

• | The condition for the DTC are no longer present and the scan tool clear DTC function is used

• | 50 ignition cycles have passed with no DTCs detected

### Diagnostic Aids

• | The temperatures are estimated figures taken by the EBTCM

• | The following conditions are other possible causes of this malfunction:

- | Excessive brake usage

- | Excessive TCS usage

- | A misadjusted or damaged stoplamp/BTSI switch

### Test Description

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

1. This step reads the TCS status.

#### DTC C1238 Brake Thermal Model Exceeded

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check
2 |

1. Turn the ignition switch to the RUN position with the engine off.
2. Using a scan tool, read the ABS/TCS DTCs.

Are there any other DTCs?

--

Go to Diagnostic Trouble Code (DTC) List for Appropriate DTC Table

Go to Step 3

3 |

1. Allow the vehicle to cool for 30 minutes after driving.
2. Using a scan tool, enter the ABS Data List and read the Brake Thermal Model Exceeded Parameter.

Is the BTM exceeded?

--

Go to Step 4

Go to Step 5

4 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | --
5 | Inspect the Stoplamp Switch for misadjustment. Is the switch misadjusted? | -- | Go to in Stop Lamp Switch Adjustment Hydraulic Brakes | Go to Diagnostic System Check