P0560 Code: System Voltage Malfunction
The engine computer saw its supply voltage missing or out of range – check fuses and feeds first.
Unverified: this manufacturer-specific definition comes from a single source or varies by model. Confirm it with a brand-specific scan tool.
At a glance
Severity: Moderate
- Meaning
- System Voltage Malfunction
- System
- Speed & Idle Control · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $10–$900
- DIY difficulty
- Easy
P0560 is the broadest of the system voltage codes, and what triggers it varies by manufacturer, so check the service information for your vehicle. On many vehicles it means the PCM lost or saw a bad reading on its constant battery feed, the unswitched circuit that keeps learned values such as idle, fuel trim and shift adaptations alive with the key off. On others it is set when voltage leaves the expected window without a clear high or low direction, in which case P0562 or P0563 often appear alongside. Blown or corroded fuses, a failing PCM power relay and loose battery connections are far more common than a bad PCM.
Can I keep driving? Usually drivable, but the car may stall, refuse to restart or shift harshly if the PCM's power feed is intermittent. Avoid long trips until the supply circuit has been checked.
How to read P0560
- P Powertrain
- 0 Generic (SAE)
- 5 Speed, idle & inputs
- 60 Specific fault
Symptoms
- Rough or unstable idle right after every start that settles after a few minutes
- Harsh or odd shifting after each start because learned shift values were lost
- Check engine light on, sometimes with a battery light
- Intermittent no-start or the engine cutting out over bumps
- Several warning lights flashing up together for a moment
- Readiness monitors resetting to 'not ready' without anyone clearing codes
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Blown, loose or corroded fuse feeding the PCM's constant battery circuit
- Loose or corroded battery terminals or main cable ends
- Charging system fault (alternator output out of range)
- Failing PCM power relay or ignition feed
- Poor PCM or engine ground
- Aftermarket accessory or remote-start wiring spliced into a PCM feed
- Weak battery that dips during cranking
Diagnosis step by step
Read freeze frame and companion codes
Note the control module voltage recorded when P0560 set and whether P0562 or P0563 are also stored. A low value points toward battery and charging, a high one toward the alternator, and a normal value with P0560 alone toward the PCM's feed circuits.
Tools: OBD-II scanner
Test every fuse that feeds the PCM
Use the wiring diagram to find the PCM's constant (battery) and switched (ignition/relay) fuses. Test both sides of each fuse with a test light or multimeter under power; a fuse can look fine yet have a cracked element or corroded blade.
Tools: Multimeter, Flashlight
Check the constant feed at the PCM with the key off
Back-probe the PCM's battery-feed pin with the key off; it should show the same voltage as the battery. Zero or a much lower reading means an open or high-resistance feed, which also explains lost idle and shift learning.
Tools: Multimeter
Tap-test the PCM power relay
With the engine idling, tap the main relay and wiggle its socket and the fuse box connectors. A stumble, stall or flickering dash while doing this identifies the intermittent connection.
Tools: Screwdriver, Flashlight
Confirm battery and charging output
Once the feeds check out, confirm the battery is charged and the alternator is regulating normally so the PCM has a steady supply to measure. If readings are clearly high or low, follow the P0563 or P0562 diagnosis.
Tools: Multimeter
Look for aftermarket wiring
Remote starters, trailer controllers and alarm systems are sometimes spliced into PCM circuits with tap connectors. Remove or properly re-wire them and retest before suspecting the PCM itself.
Tools: Flashlight, Pliers
Where the parts are
- 1Battery
- 2Alternator
- 3Engine computer (ECM)
- 4CAN bus
- 5Transmission
- 6Wheel speed sensor
- 7High-voltage battery
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace fuse and clean fuse box terminals | Yes | $10–$120 |
| Replace PCM main power relay | Yes | $40–$180 |
| Repair PCM feed or ground wiring | No | $120–$400 |
| Remove or rewire faulty aftermarket accessory | No | $80–$300 |
| Replace alternator if output is out of range | No | $400–$900 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Emissions / smog test impact
Depends
Whether P0560 turns on the check engine light depends on the vehicle. Even when it doesn't, a PCM that repeatedly loses its constant feed keeps resetting readiness monitors, which can make the car fail an OBD-II test as 'not ready'.
Frequently asked questions
How is P0560 different from P0562 and P0563?
P0562 and P0563 state a direction: voltage too low or too high. P0560 is the general fault, and on many vehicles it refers to the PCM's constant battery feed rather than the charging system itself.
Why does my car idle badly every morning and then smooth out?
If the PCM loses its constant feed with the key off, it forgets its learned idle and fuel trim values overnight and has to relearn them after each start. That relearning period is the rough idle you notice.
I just disconnected the battery and now I have P0560. Is something broken?
On some vehicles, disconnecting the battery or letting it go flat is enough to store P0560. Clear the code and see whether it returns; if it doesn't, nothing needs repairing.
Could the PCM itself be bad?
It's possible but uncommon. Replace a PCM only after proving that its fuses, relay, feeds and grounds all deliver full voltage with minimal drop, because a new PCM behaves exactly the same on a bad supply.