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/Stabiltrak 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 When 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

- 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.
- If an intermittent malfunction exists refer to Intermittents and Poor Connections.
- Check for other low voltage conditions.
- Test the charging system.
- Possible causes for DTC C1236 to set:
- A charging system malfunction.
- An excessive battery draw.
- A weak battery.
- A faulty system ground.

Test Description

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

4. Checks for a good ground.
6. Checks for battery voltage.