ABS - With Traction Control

DTC C1237: High System Supply Voltage:

DTC C1237: High System Supply Voltage Schematic:

CIRCUIT DESCRIPTION
This DTC is designed to detect high vehicle voltage levels prior to any required motor movement (initialization or ABS). If excessive voltage exists, demagnetization of the motor magnets may occur, which would eventually affect or eliminate ABS performance.

CONDITIONS FOR SETTING THE DIAGNOSTIC TROUBLE CODE (DTC)
DTC C1237 can only be set if the vehicle's speed is greater than 5 km/h (3 mph). If the switched battery voltage is greater than 17.1 volts, a malfunction exists.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS/Traction Control System (TCS) is disabled. The amber ABS and the amber TCS warning indicators are turned on.

DIAGNOSTIC AIDS
An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. The frequency of the malfunction can be checked by using the enhanced diagnostic function of the scan tool, as described in Scan Tool Diagnostics in the scan tool manual. Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness.

NOTE: J 39200 test leads must be zeroed prior to making any resistance measurements. Refer to J 39200 user's manual.