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Engine-Codes – GMC – P0689 2016 GMC Sierra

P0689 2016 GMC Sierra Code - Electronic Control Module Power Relay Sense Circuit Low

Quick Answer

The P0689 code indicates a problem with the Electronic Control Module (ECM) power relay sense circuit, specifically that the voltage level is lower than expected. Common causes include Faulty ECM Power Relay: A malfunctioning relay can fail to provide adequate voltage to the ECM, Wiring Issues: Damaged, corroded, or frayed wiring in the sense circuit can lead to low voltage readings, ECM Failure: A defective ECM itself may not process the power relay signals correctly. 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
P0689 2016 GMC Sierra indicates Electronic Control Module Power Relay Sense Circuit Low.
Common causes
Common causes include Faulty ECM Power Relay: A malfunctioning relay can fail to provide adequate voltage to the ECM, Wiring Issues: Damaged, corroded, or frayed wiring in the sense circuit can lead to low voltage readings, ECM Failure: A defective ECM itself may not process the power relay signals correctly.
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.
What is this?
Table of contents Created and updated by William Orellana on Oct 08, 2024
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Code P0689 2016 GMC Sierra Description

The P0689 code indicates a problem with the Electronic Control Module (ECM) power relay sense circuit, specifically that the voltage level is lower than expected. The ECM is a critical component in modern vehicles, responsible for managing engine performance, fuel efficiency, emissions control, and various other functions. The power relay is essential for supplying the ECM with the necessary voltage to operate correctly. When the sense circuit reports a low voltage condition, it can lead to several performance issues.

OBDII Code P0689 2016 GMC Sierra - Electronic Control Module Power Relay Sense Circuit Low
P0689 2016 GMC Sierra Code - Electronic Control Module Power Relay Sense Circuit Low

Common Causes of P0689 2016 GMC Sierra

  1. Faulty ECM Power Relay: A malfunctioning relay can fail to provide adequate voltage to the ECM.
  2. Wiring Issues: Damaged, corroded, or frayed wiring in the sense circuit can lead to low voltage readings.
  3. ECM Failure: A defective ECM itself may not process the power relay signals correctly.
  4. Poor Ground Connections: Inadequate grounding can lead to voltage drops in the circuit.
  5. Environmental Factors: Moisture or contaminants can affect electrical connections, leading to intermittent faults.

Symptoms of P0689 2016 GMC Sierra

  1. Check Engine Light: The most common symptom is the illumination of the check engine light on the dashboard.
  2. Poor Engine Performance: Drivers may notice a decrease in engine power, acceleration issues, or stalling.
  3. Reduced Fuel Efficiency: A malfunctioning ECM can lead to improper fuel-air mixture, resulting in increased fuel consumption.
  4. Difficulty Starting: The vehicle may experience starting issues, including prolonged cranking or failure to start altogether.
  5. Limp Mode Activation: The vehicle may enter a protective limp mode, limiting engine power to prevent further damage.

How to Fix P0689 2016 GMC Sierra

  1. Visual Inspection: Begin with a thorough visual inspection of the wiring and connectors associated with the ECM power relay and sense circuit for any signs of damage or corrosion.
  2. Testing the Relay: Use a multimeter to test the ECM power relay for proper operation. Replace it if it fails to meet specifications.
  3. Checking Voltage Levels: Measure the voltage at the ECM and the relay to ensure they are within the manufacturer's specified range. Address any discrepancies.
  4. Repairing Wiring: If damaged wiring is found, repair or replace the affected sections to restore proper electrical flow.
  5. ECM Replacement: If all other components are functioning correctly and the issue persists, consider replacing the ECM as a last resort.

Cost to Fix P0689 2016 GMC Sierra

The cost to diagnose and repair a P0689 code can vary significantly based on the specific issue and the labor rates in your area. On average, the total repair cost can range from $150 to $600. This estimate includes parts such as a new power relay (typically $20 to $100) and labor costs, which can vary from $80 to $150 per hour. It's important to note that labor rates can be higher at dealerships or in metropolitan areas, while independent shops may offer more competitive pricing. Always check local rates for a more precise estimate and consider obtaining multiple quotes to ensure a fair price for the repair.

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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 P0689 2016 GMC Sierra Code

1. What does OBDII code P0689 mean on a 2016 GMC Sierra?

P0689 indicates that the Electronic Control Module (ECM) power relay sense circuit is reading a voltage that is too low, signaling a potential issue with the relay or its connections.

2. What are the common symptoms of code P0689 in a 2016 GMC Sierra?

Common symptoms include difficulty starting the engine, intermittent stalling, reduced engine performance, and illuminated check engine light.

3. What causes the P0689 code in a 2016 GMC Sierra?

Common causes include a faulty ECM power relay, damaged wiring or connectors in the relay circuit, a weak battery, or a malfunctioning ECM.

4. Can a bad battery cause the P0689 code on a 2016 GMC Sierra?

Yes, a weak or failing battery can lead to low voltage in the ECM power relay sense circuit, triggering the P0689 code.

5. How do you diagnose code P0689 on a 2016 GMC Sierra?

Diagnosis involves checking the battery voltage, inspecting the ECM power relay, testing the relay circuit wiring, and verifying proper operation of the ECM.

6. Is it safe to drive a 2016 GMC Sierra with code P0689?

It’s not recommended to drive with this code, as it can lead to stalling or starting issues, potentially leaving you stranded.

7. How can you fix the P0689 code on a 2016 GMC Sierra?

Repairs may involve replacing the ECM power relay, repairing damaged wiring or connectors, cleaning corroded terminals, or replacing the ECM if necessary.

8. Can a faulty ECM trigger code P0689 on a 2016 GMC Sierra?

Yes, a malfunctioning ECM can fail to properly sense the relay voltage, causing the P0689 code to set.

9. How much does it cost to fix code P0689 on a 2016 GMC Sierra?

Repair costs vary but typically range from $50 to $200 for a power relay replacement, with additional labor costs if wiring repairs or ECM replacement is needed.

10. Can clearing the P0689 code fix the issue on a 2016 GMC Sierra?

Clearing the code may temporarily turn off the check engine light, but it won’t resolve the underlying problem causing the code. Proper diagnosis and repair are necessary.

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