Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0563 System Voltage High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

The module measures its own supply voltage. CARB allows other monitors to be suspended below 11 V, and above a maker's threshold only if the voltage itself is diagnosed – that is what these codes record. GM's engine modules and Ford's PCM set them without warning lamp. P0563 means the voltage is above its threshold: GM's engine module 18 V or more in 400 of 500 samples, type C; Saab's 9-4X above 18 V for 5 s. Typical are an overcharging regulator or a jump start or charger at 24 V. Saab's EDC16 diesel reports the same condition as P0560 instead.

Likely causes

Regulator or alternator overcharging
24 V jump start or fast charger
Missing battery or poor battery terminal (voltage spikes)
Alternator control line from the module (smart charging)

Symptoms

  • Charge warning
  • Bulbs burning out, flickering lights
  • Several modules switch off or report faults

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–700
Time0.3–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

What to check first

  1. Measure charging voltage
  2. Check regulator
  3. Inspect sense wire

Parts involved

batteryalternatormodule power supplyengine control module

Related codes

P0560P0561P0562P0620P0622

References: gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com, roushcleantech.com.