AutoCodes – GMC – P16A7 GMC

P16A7 GMC Code - Engine Controls Ignition Relay Feedback Circuit 2

Quick Answer

There are 3 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: P16A7 GMC indicates Engine Controls Ignition Relay Feedback Circuit 2.
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 1,905

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 Aug 13, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P16A7 GMC Description

There are 3 ignition voltage circuits supplied to the Engine Control Module (ECM). Two 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 2 ignition voltage circuits for greater than 1 s.

OBDII Code P16A7 GMC - Engine Controls Ignition Relay Feedback Circuit 2 - AutoCodes.com — P16A7 GMC Code - Engine Controls Ignition Relay Feedback Circuit 2

What does this mean?

What are the Possible Causes of the DTC P16A7 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 P16A7 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 P16A7 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 P16A7 GMC 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.