AutoCodes – GMC – P16D9 GMC

P16D9 GMC Code - Sensor Supply Voltage Relay Control Circuit High Voltage

Quick Answer

The Reductant Control Module Relay 1 & 2 supply ignition voltage to the Reductant Control Module. Common causes include Faulty Reductant Control Module Relay, Reductant Control Module Relay harness is open or shorted, Reductant Control Module 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: P16D9 GMC indicates Sensor Supply Voltage Relay Control Circuit High Voltage.
Common causes: Common causes include Faulty Reductant Control Module Relay, Reductant Control Module Relay harness is open or shorted, Reductant Control Module 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 1,090

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 P16D9 GMC Description

The Reductant Control Module Relay 1 & 2 supply ignition voltage to the Reductant Control Module. The Reductant Control Module Relay 2 also supplies ignition voltage to Nitrogen Oxide Sensor 1 & 2 and the Exhaust Particulate Matter Sensor. Both Reductant Control Module Relay 1&2 are controlled by a low side driver in the Engine Control Module (ECM).
The Diagnostic Trouble Code (DTC) will be set when the ECM detects an open circuit, short to voltage or short to ground on the Reductant Control Module Relay control circuit.

OBDII Code P16D9 GMC - Sensor Supply Voltage Relay Control Circuit High Voltage - AutoCodes.com — P16D9 GMC Code - Sensor Supply Voltage Relay Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P16D9 GMC?

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

How to Fix the DTC P16D9 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 P16D9 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 P16D9 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.

Frequently Asked Questions about P16D9 GMC Code

1. What are common symptoms of OBDII code P16D9 GMC?

- Common symptoms include illuminated Check Engine Light (CEL), poor engine performance, and potential stalling.

2. What causes the OBDII code P16D9 GMC to be triggered?

- This code is typically triggered by issues with the sensor supply voltage relay control circuit experiencing high voltage.

3. How serious is the OBDII code P16D9 GMC?

- While the severity can vary, it is important to address this code promptly to prevent potential engine performance issues.

4. How can I diagnose the OBDII code P16D9 GMC?

- Diagnosing this code involves checking the sensor supply voltage relay, inspecting wiring for damage, and testing the circuit for high voltage.

5. What are some repair tips for resolving the OBDII code P16D9 GMC?

- Repair tips may include replacing the faulty sensor supply voltage relay, repairing damaged wiring, and resetting the trouble code.

6. Can I drive my vehicle with OBDII code P16D9 GMC?

- It is not recommended to drive the vehicle extensively with this code present, as it may lead to further engine issues or potential stalling.

7. How much does it cost to repair OBDII code P16D9 GMC?

- The cost of repair can vary depending on the extent of the issue, but it may involve replacing the relay, fixing wiring, or seeking professional help.

8. Can I reset the OBDII code P16D9 GMC on my own?

- You may be able to reset the code using an OBDII scanner, but it is important to address the underlying issue causing the code before resetting it.

9. Are there any preventive measures to avoid OBDII code P16D9 GMC in the future?

- To prevent this code from reoccurring, regular maintenance checks, timely repairs, and ensuring proper electrical system function are recommended.

10. Will OBDII code P16D9 GMC affect my vehicle's fuel efficiency?

- In some cases, this code can impact fuel efficiency due to engine performance issues, so addressing it promptly is advisable to maintain optimal fuel economy.