P0562: System Voltage Low

What is P0562?

OBD-II Diagnostic Trouble Code P0562 is defined as “System Voltage Low.” This means that the powertrain control module (PCM) sees an actual system voltage that’s lower than the requested vehicle voltage.

When your engine is off, the battery supplies your car with the power for its electrical needs. Once the engine is cranked, the alternator takes over that job. It also replenishes the battery charge to prevent low battery voltage problems later on, especially at vehicle startup. 

When your car is running, your vehicle’s charging system (which your alternator is a part of) is responsible for maintaining a consistent vehicle voltage level.  

The voltage level for an idling engine with the headlights off typically ranges between 14.1 to 14.4 volts. 

However, suppose the charging system voltage drops below 10 volts for 60 seconds or more when the engine is idling. In that case, the powertrain control module or engine control module (ECM) sets the P0562 System Voltage Low code. 

When this happens, your dashboard Check Engine Light or Malfunction Indicator Light (MIL) will light up.

Common symptoms

Low voltage supply to the car’s battery and the rest of the electrical system can create all sorts of problems and erratic performance.

Here are some more noticeable symptoms when the P0562 code is stored:

• Check Engine Light or Malfunction Indicator Light turns on
• Battery light turns on, or the charging system amperage reads low
• Battery loses power quickly
• Vehicle transmission doesn’t shift properly
• Engine misfires or lacks power
• Engine dies at idle or won’t start
• Fuel efficiency is reduced

Many of these symptoms can be associated with other vehicle problems and codes. 

Power loss can also be caused by a dead battery or ignition system problems can trigger the misfires. This is why getting a professional to identify the root cause is your best option.

In some rare instances, the P0562 code might not exhibit any symptoms other than the lit Check Engine Light. You should get the code resolved regardless, as the underlying issue could become symptomatic, eventually leading to more serious problems.

Can I still drive?

P0562 is a pretty serious code, even when it doesn’t exhibit any symptoms. 

If the charging system isn’t functioning correctly, your battery won’t have enough juice to crank the engine at some point. If your car’s voltage level drops too low, your vehicle might stall while idling and not start again. Imagine that happening in heavy traffic or at the traffic light of a busy intersection.  

For that reason, it’s essential that you get the low voltage condition addressed. Having the P0562 code fixed will help ensure your safety on the road and that of others.

P0562 causes

Several reasons could cause a drop in the system voltage level and trigger the P0562 code, including:

• A bad alternator (most common reason)
• A defective voltage regulator
• A parasitic battery drain
• A worn-out battery or battery terminal
• Faulty charging system grounds
• A faulty B+ battery cable from the alternator to the battery
• Corroded or loose alternator wiring
• Faulty wiring between the alternator and PCM
• Blown fuses
• A defective PCM (rare)

Diagnosis

A professional mechanic will use an OBD-II scanner to diagnose the P0562 code. Here are the steps the mechanic would take to troubleshoot:

1. Check for additional codes

Your mechanic will first use an OBD-II scan tool to check if there are other codes related to the charging system. This could help pinpoint the root cause of the P0562 issue or identify other problems that might need to be addressed first.

2. Check the charging system voltage

Your mechanic will then turn on the vehicle and switch on the headlamps. They may use the high-beam lights and turn up the blower to increase the load on the charging system. Then they’ll check the battery voltage. 

A good voltage reading is something between 13.2 to 14.7 volts. If the voltage reading is less than 12 volts or more than 15 volts, there’s a problem with the charging system.   

3. Inspect PCM connections

If the code P0562 persists, they’ll inspect the PCM’s wiring, connectors, and terminals. They’ll check for signs of corrosion, burning, or fraying, which can compromise circuit integrity. 

4. Measure the PCM voltage

Your mechanic will check the ground and system voltage at the PCM if the problem continues. After safely disconnecting the harness that goes to the PCM, they’ll turn on the ignition switch and test the PCM ignition feed circuit with a DVOM. They’ll also use a test light to check the PCM ground. 

It’s possible that the PCM needs to be updated or replaced if everything else is fine.

What would be a common mistake when diagnosing P0562?

The most common mistake is an incomplete P0562 diagnosis. 

A bad battery or starter is often assumed to be the culprit, especially if you have trouble starting the vehicle. If these aren’t the root cause, replacing either component won’t solve the underlying problem, and the fault code will return. 

So always ensure that you get a complete diagnosis. This way, you won’t end up replacing parts that aren’t broken or waste money.

Possible repairs for P0562 & Costs

As the P0562 error code can stem from many different causes, the possible repairs are also multiple. Some of the most common fixes include: 

• Replacing a bad alternator
• Replacing a faulty voltage regulator
• Replacing a bad battery 
• Replacing a damaged battery cable
• Repair or replace faulty wiring
• Replace a fuse
• Update or replace a defective PCM 

If you want an idea of how much different types of P0562 repairs can cost, here’s an estimate of some common prices:

• Alternator replacement: $300 – $650
• Voltage regulator replacement: $300 – $425
• Bad battery replacement: $45 – $250
• Damaged wiring repairs or replacement: $5 – $500
• Fuse replacement: $5 – $25
• PCM repair or replacement: $500-$2,500

Please note that the final cost will also depend on your vehicle make, model, location, and labor charges.