AutoCodes – Generic – B1527

B1527 Code - Parasitic Load

Quick Answer

The components most likely to cause a parasitic draw on the battery of the vehicle are switches, relays, and control modules. Common causes include Faulty Battery, Low Battery Charge, Charging System. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B1527 indicates Parasitic Load.
Common causes: Common causes include Faulty Battery, Low Battery Charge, Charging System.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 10,576

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 21, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1527 Description

The components most likely to cause a parasitic draw on the battery of the vehicle are switches, relays, and control modules. After the ignition is turned OFF the control modules will begin to go to sleep (shut OFF). All control modules do not go to sleep at the same time, some, like the Heating, Ventilation, and Air-Conditioning (HVAC) and body control modules, may take up to 30 min or longer after turning the ignition off before going to sleep. Others such as the ON Star and keyless entry control modules may periodically wake up then go back to sleep. These are all normal conditions. The Body Control Module (BCM) monitors the state of charge of the electrical system. If the BCM senses that the state of charge at ignition On is 30% lower than what it was when the engine was running.

OBDII Code B1527 - Parasitic Load - AutoCodes.com — B1527 Code - Parasitic Load

What does this mean?

What are the Possible Causes of the DTC B1527?

Faulty Battery
Low Battery Charge
Charging System

How to Fix the DTC B1527?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1527 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1527 code?

Need more information on how to fix the B1527 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1527 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1527 Buick — Parasitic Load
B1527 Cadillac — Parasitic Load
B1527 Chevrolet — Parasitic Load
B1527 GMC — Parasitic Load

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1527 Code

1. What does the OBDII code B1527 mean?

B1527 indicates that the vehicle's onboard diagnostic system has detected a parasitic electrical load or draw when the vehicle is off, which can drain the battery.

2. What are the common symptoms of code B1527?

Symptoms include a dead or weak battery, difficulty starting the vehicle, and electrical components remaining active after the car is turned off.

3. What causes the B1527 code to appear?

Common causes include a faulty module not shutting down properly, aftermarket accessories drawing power, a damaged wiring harness, or a stuck relay.

4. Can a weak battery trigger the B1527 code?

Yes, a weak or failing battery can contribute to parasitic load issues, which may lead to the B1527 code being stored.

5. How can I diagnose the cause of the B1527 code?

Start by checking for aftermarket devices, inspecting the wiring and fuses, testing relays, and using a multimeter to measure parasitic current draw.

6. Can I drive my car with the B1527 code?

You can drive the car temporarily, but ignoring the issue may lead to a dead battery and leave you stranded, so itâ€™s best to address the problem promptly.

7. How do I fix the B1527 code?

Repairs may involve disconnecting faulty aftermarket devices, replacing stuck relays, repairing damaged wiring, or addressing issues with modules that fail to power down.

8. Can a faulty alternator cause a B1527 code?

While rare, a failing alternator with a defective diode can create a parasitic load, potentially triggering the B1527 code.

9. How much parasitic draw is considered normal?

A typical vehicle should have a parasitic draw of 50 milliamps (mA) or less. Readings higher than this may indicate an issue.

10. Do I need a professional mechanic to fix a B1527 code?

If youâ€™re comfortable with electrical diagnostics, you can attempt repairs yourself. However, for complex or hard-to-diagnose issues, itâ€™s recommended to seek help from a qualified mechanic.