AutoCodes – Generic – P16AF

P16AF Code - Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage

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: P16AF indicates Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage.
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 2,421

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
FAQs
Comments
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Code P16AF 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 the engine controls ignition relay feedback circuit 2 is less than 5 V.

OBDII Code P16AF - Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage - AutoCodes.com — P16AF Code - Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage

What does this mean?

What are the Possible Causes of the DTC P16AF?

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 P16AF?

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 P16AF 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 P16AF code?

Need more information on how to fix the P16AF code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P16AF code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P16AF Buick — Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage
P16AF Cadillac — Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage
P16AF Chevrolet — Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage
P16AF GMC — Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage

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 P16AF Code

1. What are the common symptoms of OBDII code P16AF?

- Common symptoms include engine stalling, rough idling, and difficulty starting the vehicle.

2. What causes the Engine Controls Ignition Relay Feedback Circuit 2 Low Voltage code (P16AF)?

- The code P16AF is typically triggered by a faulty ignition relay, damaged wiring, or a problem with the engine control module (ECM).

3. How can I diagnose the cause of OBDII code P16AF?

- A thorough inspection of the ignition relay, wiring, and ECM is recommended. Testing the voltage at the relay and checking for any loose connections can help pinpoint the issue.

4. Can a DIYer repair OBDII code P16AF?

- DIY repairs for code P16AF may include replacing the faulty ignition relay, repairing damaged wiring, or resetting the ECM. However, advanced diagnostics and repairs may require professional assistance.

5. What are the potential risks of ignoring OBDII code P16AF?

- Ignoring code P16AF can lead to further engine performance issues, increased fuel consumption, and potential safety hazards due to unreliable ignition system operation.

6. Is it safe to drive with OBDII code P16AF active?

- It is not recommended to drive with code P16AF active, as it can cause unexpected engine behavior and potentially leave you stranded if the vehicle stalls.

7. How much does it cost to repair OBDII code P16AF?

- Repair costs for code P16AF can vary depending on the underlying issue. Simple fixes like replacing the ignition relay may cost around $50-$200, while more complex repairs involving the ECM could cost several hundred dollars.

8. Can a bad battery cause OBDII code P16AF to appear?

- A weak or failing battery can sometimes cause voltage issues that trigger code P16AF. It's advisable to have the battery tested as part of the diagnostic process.

9. How long does it typically take to repair OBDII code P16AF?

- The repair time for code P16AF can vary based on the specific cause. Simple fixes like replacing a relay may take an hour or two, while more intricate repairs could take several hours or longer.

10. Does clearing the OBDII code P16AF reset the vehicle's computer?

- Clearing the code may reset the ECM's error memory, but if the underlying issue is not addressed, the code is likely to reappear. It's important to diagnose and fix the root cause of the problem.