01236 is the Audi and Volkswagen code for the safety battery terminal, the pyrofuse that cuts battery power in a crash. It is a pyrotechnic device on a monitored circuit, and the controller has found that circuit out of range.
The safety battery terminal sits on the positive battery post and holds a small pyrotechnic charge. In a crash the controller fires it, which disconnects the battery from the car and reduces the risk of an electrical fire. Since it is a firing device, the controller watches its loop the same way it watches an airbag igniter and stores 01236 when the reading is wrong.
There are two very different situations behind this code. One is a wiring or connection problem at the battery, which is common because that terminal is disturbed every time the battery is serviced. The other is a pyrofuse that has already fired in a crash, which leaves the circuit open permanently until the terminal assembly is replaced.
01236 is a live circuit reading rather than a stored crash record. The controller measures the loop at each self test, so it clears on its own when the circuit is restored. Crash data is a separate, permanent entry written at deployment, and on a car whose pyrofuse has fired, both conditions are usually present at once.
A reset does not reconnect a fired pyrofuse or repair a loose connector, and the controller stores 01236 again on the next key cycle. Replace the terminal assembly or fix the connection first. If the car was in a crash and the controller is also locked on stored deployment data, mail us the controller and we clear that record after the electrical repairs are done.
The safety battery terminal carries this code on Audi and on Volkswagen. The part sits in the same place on either brand and gets disturbed for the same reason, which is routine battery work.
Open the battery box and look at the positive terminal first, since the small control connector there gets left unplugged after battery replacement more than anything else on this list. Check whether the pyrofuse has fired, because a car that was in a collision needs the terminal assembly replaced rather than repaired. Clean and tighten the clamp while you are in there, and check the connector for acid corrosion. Related codes: 01228, 01578, B1369.
Trace the wiring and connectors first. If the module still holds the fault after the repair, mail it to us and we will clear it.
Genuine OEM, tested, and shipped ground from Jacksonville, Arkansas.
Do not see it listed? Request a part or call 501-988-0611.