What it means
The injector group A supply voltage exceeds the calibrated upper limit. Often a sign of a short to battery voltage on the supply line, an over-charging alternator or an internal driver failure.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Injector group A uses a shared power supply, while the ECU switches the individual injectors. This code sets when the monitored group A supply voltage exceeds its calibrated upper limit, which may indicate an unintended connection to battery voltage or abnormal charging voltage.
Common causes
Most likely first.
- Wire shorted to battery voltage
- Charging system overvoltage
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Misfire or rough idle on the affected cylinder
- Increased fuel consumption
- Possible fuel smell or smoke from exhaust
How to diagnose it
- Save freeze-frame data and check for charging-system, injector supply, and misfire codes to see whether the high reading coincided with engine operation or charging.
- Check live system voltage and charging behavior against the manufacturer’s specification before focusing on the injector circuit.
- With the ignition off, inspect group A wiring and connectors for rubbed insulation, pin damage, corrosion, or contact with a battery-fed wire.
- Measure group A supply voltage under the conditions specified by the manufacturer and compare it with the related power source.
- If voltage remains high, trace the circuit for a short to battery voltage and test the relay and ECU-controlled circuit according to the wiring diagram.
Common fixes
- Repair group A wiring that is shorted to a battery-fed circuit.
- Clean or repair damaged or corroded connector terminals.
- Repair the charging system if its output exceeds the manufacturer’s specification.
- Replace a faulty supply relay or driver component only after circuit testing identifies it.
Can I keep driving?
Avoid driving if the engine misfires, runs roughly, or the charging system is overcharging; either condition can cause further component damage. Stop if there is smoke, a strong fuel smell, or worsening drivability.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.