U0062: Vehicle Communication Bus D (-) High
What to do
Disconnect the battery if the car is going to sit waiting for repair — see U0059. Battery voltage on a network wire is both damaging and keeps the car awake, so the time it spends parked is time the computers are being stressed.
Two observations are worth reporting.
Does it appear only when something power-hungry is switched on? That is a bad earth shared with the network wiring — see U0035.
Or does it appear only when the car is parked? That points at something that is meant to stay awake — a tracker, an alarm, a telematics or insurance box — whose earth connection is not good enough for the current it draws when it wakes up and does its job. The device works fine; its earth rises under load, and the network wire beside it picks that up.
Either way, mention everything that has been fitted to the car and ask for the earth connections to be checked, not just the power feeds. The earth is the half installers treat as unimportant, and it is the half that causes this.
What this code means
The negative line of vehicle communication bus D is being held high. Everything at U0059 applies, including the instruction to disconnect the battery if the vehicle is standing — because a bus held at voltage is both damaging and awake, so time spent parked is time spent exposed.
And U0008's point holds: this conductor runs nearest the earth wiring, so a bad earth on an accessory installation reaches it first, giving the load-dependent signature at U0035.
One thing is worth adding for this network specifically. A fault that only appears when the vehicle is parked and only involves the earth side is very often a device that is supposed to stay awake — a tracker, an alarm, a telematics box — whose earth is inadequate for the current it draws when it activates. The device works, the earth rises under its load, and the network sees voltage on the conductor beside it.
Which points the investigation at the accessory's installation rather than at the vehicle, and makes unplugging it the first and cheapest test.
Likely causes
Start here
- Corroded earth connection · moderate
- Poor wiring splice in an aftermarket installation · moderate
- Wiring shorted to voltage · moderate
- Faulty aftermarket alarm or immobiliser installation · moderate
Less common
- Damaged data bus wiring · moderate
- Intermittent wiring fault · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
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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