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. Refer to Charging System Check in Engine Electrical. |
| • | 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.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check | ||||
2 | Test the charging system. Refer to Charging System Check in Engine Electrical. Is the charging system OK? | -- | Go to Step 3 | Go to Charging System Check in Engine Electrical | ||||
3 |
Is there evidence of any corrosion or damage? | -- | Go to Step 7 | Go to Step 4 | ||||
Is the resistance less than the specified value? | 2 ohms | Go to Step 5 | Go to Step 8 | |||||
5 | Use the DMM in order to measure the voltage between the following terminals of the J 39700 :
Is the voltage greater than the specified value for both measurements? | 10.5 V | Go to Step 6 | Go to Battery Load Test in Engine Electrical | ||||
Is the voltage greater than the specified value? | 10.5 V | Go to Step 9 | Go to Battery Load Test in Engine Electrical | |||||
7 | Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check | -- | ||||
8 | Repair an open or high resistance in CKT 1651. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Diagnostic System Check | -- | ||||
9 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | Go to Diagnostic System Check | -- |
