DTC C1237 detects high vehicle voltage levels prior to any required motor movement (initialization or ABS). Damage to the system may occur if excessive voltage exists.
| • | DTC C1237 can set only if the vehicle's speed is greater than 5 km/h (3 mph). | 
| • | A malfunction exists if the switched battery voltage is greater than 17 volts. | 
| • | A malfunction DTC stores. | 
| • | The ABS disables. | 
| • | The ABS warning indicator turns ON. | 
| • | 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. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition off. | 
Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.
Ensure the vehicle's charging system is working properly.
Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual.
Step  | Action  | Value(s)  | Yes  | No  | 
|---|---|---|---|---|
1  | Was the Diagnostic System Check performed?  | --  | Go to Diagnostic System Check  | |
2  | 
 Is the voltage less than or equal to the specified voltage?  | 16 V  | ||
3  | 
 Is the voltage less than or equal to the specified range?  | 16 V  | Go to Wiring Systems  | |
4  | 
 Does DTC C1237 set as a current DTC?  | --  | ||
5  | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete?  | --  | Go to Diagnostic System Check  | --  | 
6  | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. Is the action complete?  | --  | System OK  | --  |