What does it mean?
U1007 is a Network (CAN bus, module communications) fault code. It indicates: DIS High Voltage Detected .
Symptoms
- Audio system mutes or shuts down to protect itself, then works again later
- Headlights unusually bright and interior lighting flaring
- Battery warning lamp on or flickering
- Bulbs failing more often than normal and a hot or swollen battery
- Multiple modules storing high voltage or communication codes at the same time
- Smell from the battery area in severe overcharging cases
Likely causes
- Faulty voltage regulator or alternator allowing overcharging
- Poor connection in the alternator sensing circuit, so the regulator cannot see true system voltage
- Corroded or loose main earth causing the regulator to overcompensate
- Battery in poor condition or with an internal open cell, letting system voltage spike
- Incorrect jump starting or the use of an unsuitable external charger or booster
- Accessories fitted after manufacture feeding voltage back into the system
- Faulty voltage sensing input inside the audio module, considered only after charging is verified
How to fix it
- Measure the charging voltage at the battery at idle and at raised RPM, and compare it with the specified range before touching the audio system
- If voltage is high, check the alternator sensing wire and its connector for corrosion and high resistance
- Do voltage drop tests on the main positive cable and the main earth between the alternator, battery and body
- Inspect the battery for age, damage and internal faults; a failing battery can let voltage rise
- Ask about recent jump starts or the use of an external charger, which can leave a spike code stored
- Disconnect electrical accessories added after manufacture and retest
- Repair or replace the regulator or alternator as the readings indicate, then clear the code and recheck
- Only if charging voltage is proven correct should the audio module's own voltage sensing be questioned