U0036–U0072 Vehicle Communication Bus A (-) shorted to Bus A (+)
The ECU has logged a fault on U0036. The definition below is the exact wording the standard uses for this code.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
U0036 | Vehicle Communication Bus A (-) shorted to Bus A (+) | Investigate soon |
U0045 | Vehicle Communication Bus B (-) shorted to Bus B (+) | Investigate soon |
U0054 | Vehicle Communication Bus C (-) shorted to Bus C (+) | Investigate soon |
U0063 | Vehicle Communication Bus D (-) shorted to Bus D (+) | Investigate soon |
U0072 | Vehicle Communication Bus E (-) shorted to Bus E (+) | Investigate soon |
The definition
U0036: Vehicle Communication Bus A (-) shorted to Bus A (+).
U0036 is a network code (communication between control modules), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
- Check the connector at the part for corrosion, and that it is fully seated.
- Clear the code and see whether it returns, and under what conditions.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does U0036 mean?
U0036 means Vehicle Communication Bus A (-) shorted to Bus A (+). It is logged when the ECU sees this circuit outside its expected operating window.
Can I drive with U0036?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.