C1236

Circuit Description
This DTC is used to monitor the voltage level available to the EBCM. If the voltage drops below specific levels at specific times, full performance of the ABS system cannot be guaranteed. During an ABS event, there are several current requirements that will cause battery voltage to drop. Because of this voltage is monitored prior to an ABS event and also during an ABS event operation when voltage may drop significantly.


Conditions for Running the DTC
^ The vehicle speed is greater than 8 km/h (5 mph).
^ The electronic brake control relay is commanded ON.


Conditions for Setting the DTC
One of the following conditions exists for 0.72 seconds:
^ During initialization or when the system is not in ABS, the ignition positive voltage is less than 10.5 volts.
^ When the system is in ABS, the ignition positive voltage is less than 9 volts.


Action Taken When the DTC Sets
^ ABS is disabled.
^ The ABS warning indicator turns ON.


Conditions for Clearing the DTC
^ 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.


Diagnostic Aids
^ Ensure the starting and charging systems are in proper working order. The battery should be fully charged and in good condition before beginning the diagnostic table. Refer to Battery Check in Engine Electrical.
^ The following are possible causes of this DTC:
- A charging system malfunction
- An excessive battery draw
- A weak battery
- A faulty system ground
^ Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.


Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step uses the scan tool to check the ignition positive voltage to the EBCM.
3. This step checks the battery positive voltage circuit.
4. This step checks the module ground circuit.