AutoCodes – Cadillac – P16BC Cadillac

P16BC Cadillac 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 Cadillac 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 416

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

What does this mean?

What are the Possible Causes of the DTC P16BC Cadillac?

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 Cadillac?

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 Cadillac 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.

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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 Cadillac Code

1. What does the OBDII code P16BC mean on a Cadillac?

The P16BC code indicates an issue with the Engine Controls Ignition Relay Feedback Circuit 3, which monitors and controls the ignition relay's operation.

2. What are the common symptoms of the P16BC code on a Cadillac?

Symptoms may include difficulty starting the engine, random stalling, engine misfires, and the Check Engine Light being illuminated.

3. What causes the P16BC code to appear?

Common causes include a faulty ignition relay, damaged wiring or connectors in the feedback circuit, a malfunctioning Engine Control Module (ECM), or poor electrical connections.

4. Can I drive my Cadillac with the P16BC code?

Driving with the P16BC code is not recommended as it can lead to engine performance issues, potential stalling, or further damage to electrical components.

5. How do I diagnose the P16BC code on my Cadillac?

Start by inspecting the ignition relay and its circuit for damage or corrosion. Use a multimeter to test the relay and check the circuit for continuity. Scan live data with an OBDII scanner to confirm the issue.

6. How do I fix the P16BC code on my Cadillac?

Repairs may include replacing the faulty ignition relay, repairing damaged wiring, cleaning corroded connectors, or reprogramming or replacing the ECM if necessary.

7. Can a blown fuse cause the P16BC code?

Yes, a blown fuse in the ignition relay circuit can disrupt the circuit and trigger the P16BC code.

8. How much does it cost to fix the P16BC code on a Cadillac?

Repair costs can range from $50 to $300, depending on whether itâ€™s a simple relay replacement or requires more extensive electrical or ECM work.

9. What tools are needed to troubleshoot the P16BC code?

Youâ€™ll need an OBDII scanner, a multimeter, and possibly wiring diagrams for your specific Cadillac model to diagnose and repair the issue effectively.

10. Can a weak battery cause the P16BC code on a Cadillac?

Yes, a weak or failing battery can cause voltage irregularities that may affect the ignition relay circuit and trigger the P16BC code.