AutoCodes – GMC – P16BC GMC

P16BC GMC Code - Engine Controls Ignition Relay Feedback Circuit 3

Quick Answer

There are 4 ignition voltage circuits supplied to the Engine Control Module (ECM). Common causes include Faulty Engine Controls Ignition Relay, Engine Controls Ignition Relay harness is open or shorted, Engine Controls Ignition Relay circuit poor electrical connection. 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: P16BC GMC indicates Engine Controls Ignition Relay Feedback Circuit 3.
Common causes: Common causes include Faulty Engine Controls Ignition Relay, Engine Controls Ignition Relay harness is open or shorted, Engine Controls Ignition Relay circuit poor electrical connection.
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 1,431

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 Jul 26, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P16BC GMC Description

There are 4 ignition voltage circuits supplied to the Engine Control Module (ECM). Three are supplied by the Engine Controls Ignition Relay, and the other is supplied by the ignition main relay. The ECM monitors and compares the ignition voltage supplied by the 2 relays. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the voltage level difference is greater than 3 V between the Engine Controls Ignition Relay feedback circuit 3 and the ignition 1 signal circuit for greater than 1 s.

OBDII Code P16BC GMC - Engine Controls Ignition Relay Feedback Circuit 3 - AutoCodes.com — P16BC GMC Code - Engine Controls Ignition Relay Feedback Circuit 3

What does this mean?

What are the Possible Causes of the DTC P16BC GMC?

Faulty Engine Controls Ignition Relay
Engine Controls Ignition Relay harness is open or shorted
Engine Controls Ignition Relay circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P16BC GMC?

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 P16BC GMC 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 P16BC GMC code?

Need more information on how to fix the P16BC GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P16BC GMC Code

1. What are the common symptoms of OBDII code P16BC GMC?

The common symptoms of OBDII code P16BC GMC include engine misfires, rough idling, stalling, and difficulty starting the vehicle.

2. What can cause the OBDII code P16BC GMC to trigger?

The OBDII code P16BC GMC is triggered when there is a problem with the Engine Controls Ignition Relay Feedback Circuit 3, which can be caused by a faulty ignition relay, wiring issues, or a malfunctioning engine control module.

3. How do I diagnose the OBDII code P16BC GMC?

Diagnosing the OBDII code P16BC GMC involves using a scan tool to read the code and then performing a thorough inspection of the ignition relay and related circuitry to identify any issues.

4. Can I still drive my vehicle with the OBDII code P16BC GMC?

It is not recommended to drive your vehicle with the OBDII code P16BC GMC present, as it can lead to further damage to the engine or other components if left unresolved.

5. How can I repair the OBDII code P16BC GMC?

To repair the OBDII code P16BC GMC, you may need to replace the faulty ignition relay, repair any damaged wiring, or reprogram the engine control module if necessary.

6. Are there any DIY tips for fixing the OBDII code P16BC GMC?

While some basic electrical knowledge is required, you may be able to replace the ignition relay yourself if you have the proper tools and access to a repair manual for your vehicle.

7. Is it necessary to reset the OBDII code P16BC GMC after repairs?

Yes, it is recommended to reset the OBDII code P16BC GMC after completing any repairs to clear the code from the system and ensure the issue has been resolved.

8. How serious is the OBDII code P16BC GMC?

The OBDII code P16BC GMC should be addressed promptly to prevent further engine issues and potential breakdowns. Ignoring this code can lead to more severe problems over time.

9. Can a bad battery cause the OBDII code P16BC GMC to appear?

A weak or failing battery can sometimes cause electrical issues that may trigger the OBDII code P16BC GMC. It is advisable to check the battery's condition as part of the diagnostic process.

10. How long does it typically take to repair the OBDII code P16BC GMC?

The repair time for the OBDII code P16BC GMC can vary depending on the exact cause of the issue and the availability of replacement parts. In general, it may take a few hours to a day to complete the repair.