P0560 – System voltage malfunction

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By Reinier (Contact Me)
Last Updated 2016-11-17
Automobile Repair Shop Owner
CodeFault LocationProbable Cause
P0560 System voltage malfunction
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Wiring, poor connection, battery, alternator

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Table of Contents

  1. What Does Code P0560 Mean?
  2. What are the common causes of code P0560 ?
  3. What are the symptoms of code P0560 ?
  4. How do you troubleshoot code P0560 ?
  5. Codes Related to P0560
  6. Get Help with P0560

What Does Code P0560 Mean?

OBD II fault code P0560 is defined as “System Voltage Malfunction” and is set when the PCM (Powertrain Control Module) detects an abnormal voltage value from the battery, charging, or starting system(s).

When the ignition is turned to the “ON” position, the PCM performs a check of the charging, starting, and battery system, and when the engine is running, the PCM expects to find a system voltage of between 13.8-, and 14.4 volts in a fully functional system. A reading that is lower or higher than this range will trigger the CHECK ENGINE, or SERVICE ENGINE soon warning light, and code P0560 will be set and stored.

The image below shows corrosion on battery terminals, which is a common cause of code P0560.


What are the common causes of code P0560 ?

The most common cause(s) of code P0560 by far, are defective batteries and alternators, with defective starter motors following close behind. Other possible causes of code P0560 include:

  • Incorrect, or unsuitable batteries, especially in diesel vehicles. Always check that the vehicle is fitted with a suitable battery.

  • Incorrect, or unsuitable alternators. Always check that the alternator is rated for the vehicle, as well as for all aftermarket accessories fitted.

  • Large battery drainages caused by short circuits in wiring, and/or electrical components.

  • Inhibited current flow throughout the electrical system caused by poor or insufficient primary and secondary ground connections.

  • Check for corrosion on battery terminals, or improperly tightened battery terminals.

  • Open circuits in associated wiring.

  • Check for excessive electrical resistance(s) in associated wiring.

  • Wiring that is damaged, or chafed through against bodywork, causing intermittent short circuits as a result.

  • After market electrical accessories such as sound systems, security systems, dual batteries, and auxiliary lights that are poorly, or incorrectly installed.

What are the symptoms of code P0560 ?

Possible symptoms of code P0560 are many and varied, depending on the application and installed equipment. The most common symptoms could include-

  • Illuminated CHECK ENGINE light.

  • Illuminated charging/battery warning light.

  • Hard, difficult, or no-start conditions.

  • Frequent, or unpredictable engine stalling.

  • Increased fuel consumption over extended periods.

  • Harsh, erratic, or unpredictable shifting on automatic transmissions.

  • Erratic instrument readings.

  • Frozen instruments on some GM products if the PCM has failed.

  • Constant drain on the battery.

NOTE: Depending on the degree of deviation from the predefined range of the system voltage, other symptoms may be present. In these cases, other codes, some of which could be make and model specific, may be present when erratic, sporadic, or intermittent malfunctions occur in peripheral systems, such as-

  • Infotainment systems.

  • Security, anti-theft, and or anti-highjacking systems.

  • Central locking systems.

  • Audio, navigation, and/or telephony systems.

  • Stored settings for power-adjustable seats and automatic climate control systems may be lost.

NOTE: Not all of the above symptoms will always be present in all cases. However, on some vehicles, depending on the degree of deviation from the system voltage (and fitted equipment), there may be no outward symptoms of code P0560 present other than a stored code and an illuminated check engine light.

How do you troubleshoot code P0560 ?

WARNING: Troubleshooting code P0560 often involves disconnecting the battery. Do NOT disconnect the battery on any vehicle unless a memory saving device is installed to keep critical systems powered up when the battery is not connected. The PCM’s on many Honda products are particularly susceptible to damage when the battery is disconnected without suitable precautions being taken, but the PCM on any vehicle could potentially suffer damage when battery power is removed.

Step 1

Since there may be other codes present, extract all codes and record all freeze frame data. This data may be of use when an intermittent fault is identified.

Step 2

Check that the battery is fully charged, and inspect the battery for signs of acid accumulation on the battery terminals. Also, check for loose terminal connections, and clean, repair, or replace terminals as required. Make sure all electrical consumers are turned off or deactivated, and check the system to ensure that there is no drain on the battery. If a drain is found, isolate all circuits in turn to identify the circuit responsible, and repair as required.

Pay particular attention to wiring that is damaged, short circuited, or electrical connectors that are corroded. Repair all faults as required, and retest the system to see if the code or related codes return.

Step 3

At this point, also load-test the battery, and check the starter motor current draw. Replace the battery if it is found to be defective, and repair/replace the starter motor if required. Clear all codes, and retest the system to see if the fault returns. If however, the battery and starter perform within the specifications stated in the manual, and no faults are found in the wiring, suspect a defective alternator.

Step 4

Remove the memory saving device if fitted, make sure that all wiring is connected, leave the code reader connected, and check the alternator output with the engine running. If the alternator output reading does not exceed 14 volts, do not assume that the alternator is defective. First, check all primary and secondary ground connections to make sure that all connections are sound. Bad ground connections often cause overheating at the connection points, so check all cable terminations for signs of scorching, burning, or arcing. Repair as required.

NOTE: With the engine running, use a multimeter to check the alternator output on the battery poles. Bad contact between the terminals and the posts can cause the battery not to charge properly, which can cause code P0560 to be set. Repeat the test on the battery terminals; the reading should closely match the reading obtained from the scanner or code reader, as well as the value obtained from the battery poles.

Clean/repair, or replace suspect battery terminals to ensure proper contact between the terminals and the battery poles. Note that the alternator output should be between 14.2 volts with the engine at idle-, and around 14.6 volts when the engine speed is raised.

TIP: A reading of more than 14.6 volts is often indicative of an overcharging condition on most applications, but some battery types require higher charge rates. In these cases, alternators are designed to deliver the higher rate, but consult the relevant manual to determine the correct battery/alternator combination for the vehicle being worked on. Ill-considered, “upgraded” batteries and alternators can cause a wide variety of electrical issues, of which code P0560 is only one.

If the battery and alternator are found not to be compatible, replace the mismatched component(s), and retest the system to see if the code returns.

Step 5

If the code persists, and no faults are present in the wiring, but the charge rate does not correspond to specified values, the alternator is defective. However, this should be confirmed with the scanner, or where a scanner is not available, a multimeter should be used to confirm a defective alternator. Consult the manual on the correct testing procedures when using a multimeter to prevent accidental short circuits.

NOTE: Some models, most notably some Chrysler and Mazda models use the PCM to monitor, and/or control the alternator output; these alternators cannot be tested on a test bench, since the PCM is not connected to the alternator. In these cases, the alternator is best replaced with a new unit, as opposed to a rebuilt unit. Since rebuilt alternators for affected vehicles cannot be tested, consult the relevant manual to determine if the alternator on the vehicle being worked on can be repaired and tested on a test bench.

Step 6

If the alternator is replaced, double check to make sure all connections are secure (including the battery terminals), remove the memory saving device, clear all codes, and operate the vehicle with a scanner connected to monitor the electrical system.

NOTE: In cases where an incorrect system voltage had affected peripheral systems, these systems might require resetting/recalibration to restore full functionality. At this point, it is unlikely that P0560 will return, but other codes might; record freeze frame data for all other codes, and reset/recalibrate all peripheral systems as required. Operate, and retest the vehicle to ensure that all repair operations were successful.

Step 7

The steps outlined above apply to most vehicles, and they should resolve code P0560. However, if the code returns it is likely that there may be an intermittent fault present, which may have to be allowed to worsen before an accurate diagnosis and definitive repair can be made.

NOTE: Bear in mind that although PCM failures are rare, there is a distinct possibility that an abnormal system voltage can damage the PCM if the PCM controls the alternator output. If this is suspected, replace the PCM, reprogram it, and test the vehicle to see if any codes return.

  • P0561 – Relates to System Voltage Unstable.

  • P0562 – Relates to System Voltage Low.

  • P0563 – Relates to System Voltage High.

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