DTC C1236 Low System Supply Voltage. Chevrolet Corvette 1997

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1997 🢒 Corvette 🢒 DTC 🢒 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 cannot be guaranteed. During ABS/TCS operation, there are several current requirements that will cause battery voltage to drop. Because of this, voltage is monitored prior to ABS/TCS operation to indicate good charging system condition and also during ABS/TCS operation when voltage may drop significantly.

Conditions for Setting the DTC

DTC C1236 can only be set if the vehicle's speed is greater than 8 km/h (5 mph). If both the battery and ignition voltages are less than 10.5 volts, a malfunction DTC will set.

Action Taken When the DTC Sets

A malfunction DTC is stored, ABS/TCS is disabled and the ABS and Traction Control Indicators are turned ON.

Conditions for Clearing the DTC

•	Condition for DTC is no longer present and Scan Tool clear DTC function is used.

•	50 Ignition cycles have passed with no DTC(s) detected.

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 General Electrical Diagnosis in Wiring Systems.

•	Check for other low voltage conditions.

•	Test the charging system. Refer to Starter and Charging System Check in Engine Electrical.

•	Possible causes for DTC C1236 to set::

-	Charging System Malfunction.

-	Excessive Battery Draw.

-	Weak Battery.

-	Faulty system ground.

Test Description

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

Checks for a good ground.

Checks for battery voltage.

DTC C1236 Low System Voltage

Step	Action	Value(s)	Yes	No
1	Was the Diagnostic System Check performed?	--	Go to Step 2	Go to Diagnostic System Check
2	Check the charging system. Refer to Starter and Charging System Check in Engine Electrical. Is the Charging System OK?	--	Go to Step 3	Go to Starter and Charging System Check in Engine Electrical
3	Turn the ignition switch to the OFF position. Disconnect the EBTCM harness connector and inspect both the harness connector and the EBTCM connector for signs of corrosion or damage. Is their evidence of any corrosion or damage?	--	Go to Step 7	Go to Step 4
4	Install J 39700 Universal Pinout Box using J 39700-25 cable adapter between the EBTCM harness connector and the EBTCM. Using J 39200 DMM measure the resistance between terminal B of J 39700 and a good ground. Is the resistance within the range specified in the value(s) column?	0 - 2ohms	Go to Step 5	Go to Step 8
5	Measure the voltage between terminals D and B of J 39700 . Is the voltage within the range specified in the value(s) column?	Above 10.5V	Go to Step 6	Go to Battery Load Test in Engine Electrical
6	Turn the ignition switch to the ON position, engine OFF. Measure the voltage at terminals A and B of J 39700 . Is the voltage within the range specified in the value(s) column?	Above 10.5V	Go to Step 9	Go to Battery Load Test in Engine Electrical
7	Repair as necessary Is the repair complete?	--	Go to Diagnostic System Check	--
8	Repair open or high resistance in CKT 1251. Refer to o Wiring Repairs in Wiring Systems. Is the repair complete?	--	Go to Diagnostic System Check	--
9	Replace the EBTCM. Refer to Electronic Brake and Traction Control Module . Is the replacement complete?	--	Go to Diagnostic System Check	--