U0072: Vehicle Communication Bus E (-) Shorted to Bus E (+)
What to do
Expect a set of systems to have stopped completely rather than working badly, and possibly a garage saying their diagnostic tool struggles to connect.
The two wires carrying this network are touching each other, which cancels the signal entirely.
One test confirms it with no manufacturer data at all: near zero ohms across the pair, which is wrong on every network there is.
And here is something worth mentioning, because it may close an old question. If this car has had unexplained electrical oddities in the past — a dashboard that lit up and cleared, faults nobody could reproduce — this is very probably the same damage, earlier. A crushed or pierced loom makes and breaks contact for a long time before it settles into a permanent short.
So this repair likely fixes both, and it is worth confirming with the garage rather than being left wondering whether the ghosts will come back.
Two wires twisted together only touch for physical reasons: a loom crushed by a panel or a fixing, a screw through the harness during a repair or an installation, water bridging a connector, or rodents.
What this code means
The two lines of vehicle communication bus E are shorted together. See U0009 for why joining a differential pair cancels the signal completely, and U0036 for why this is the one fault on a lettered bus that needs no manufacturer data to confirm.
And it is the one fault on this network that ends the ambiguity U0064 is about.
An intermittent bus fault produces a scatter of codes and no explanation. A dead short produces a network that has stopped, a measurement of near zero ohms, and a definite answer. So where a vehicle has a history of unreproducible electrical faults and now presents with this, the two are very probably the same damage at two stages — a loom crushed or pierced, making and breaking, until it settled into a permanent short.
Which means the repair closes the older question too, and it is worth confirming rather than leaving the owner expecting the intermittent faults to return.
The physical causes are U0009's short list: a loom crushed by a panel, a bracket or a fixing; a screw or self-tapper through a harness; water bridging a connector; rodent damage stripping both conductors at one point.
Likely causes
Start here
- Bus wires shorted together · moderate
- Damaged wiring harness · moderate
- Water ingress into connector · moderate
- Damaged data bus wiring · moderate
Less common
- Intermittent wiring fault · moderate
- Poor wiring splice in an aftermarket installation · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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