C1236

DTC C1236 Low System Supply Voltage:

CIRCUIT DESCRIPTION
This circuit is used to monitor the voltage level available to the EBTCM. If the voltage drops below 10.5 volts, full performance of the ABS/TCS/Stabilitrak is not guaranteed. During ABS/TCS/Stabilitrak operation, several current requirements will cause a drop in battery voltage. Prior to ABS/TCS/Stabilitrak operation, the circuit monitors voltage in order to indicate a good charging system condition. The circuit also monitors the voltage during ABS/TCS/Stabilitrak operation, when the voltage may drop significantly

CONDITIONS FOR SETTING THE DTC
All of the following conditions occur:
^ The vehicle speed is greater than 8 km/h (5 mph).
^ The battery positive voltage (B+) is less than 10.5 volts.
^ The ignition voltage is less than 10.5 volts.

ACTION TAKEN WITH THE DTC SETS
^ A malfunction DTC is stored.
^ The ABS/TCS/Stabilitrak is disabled.
^ The ABS indicator is turned ON.
^ The TRACTION CONTROL indicator is turned ON. The DIC displays the SERVICE STABILITY SYS message.

CONDITIONS FOR CLEARING THE DTC
^ The condition for DTC is no longer present and you used scan tool Clear DTCs function.
^ The condition for DTC is no longer present and you used the On-Board Clear DTCs function.
^ The EBTCM does not detect the DTC in 50 drive cycles.

DIAGNOSTIC AIDS
^ Thoroughly inspect the wiring and the connectors. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis. Misdiagnosis may cause part replacement with reappearance of the malfunction.
^ An intermittent malfunction may be caused by poor connections, broken insulation, or a wire that is broke inside the insulation.
^ If an intermittent malfunction exists refer to Intermittents and Poor Connections Diagnosis in Diagnostic Aids.
^ Check for other low voltage conditions.
^ Test the charging system.
^ Possible low voltage condition causes may include:
- Charging system malfunction
- Excessive battery draw
- Weak battery
- Faulty system ground

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
4. This step checks for a good ground.
6. This step checks for battery voltage.