AutoCodes – GMC – P2689 GMC

P2689 GMC Code - Fuel Heater Relay Control Circuit High Voltage

Quick Answer

Ignition voltage is supplied to the coil side of the fuel heater relay whenever the ignition is On. Common causes include Faulty Fuel Supply Heater, Fuel Supply Heater harness is open or shorted, Fuel Supply Heater 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: P2689 GMC indicates Fuel Heater Relay Control Circuit High Voltage.
Common causes: Common causes include Faulty Fuel Supply Heater, Fuel Supply Heater harness is open or shorted, Fuel Supply Heater 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 523

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 01, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P2689 GMC Description

Ignition voltage is supplied to the coil side of the fuel heater relay whenever the ignition is On. The Engine Control Module (ECM) provides a ground to control the fuel heater relay. When the ECM is commanding the fuel heater On, the voltage of the control circuit should be low, near 0 V. When the ECM is commanding the fuel heater Off, the voltage of the control circuit should be high, near battery voltage. The Diagnostic Trouble Code (DTC) will be set when the ECM detects the fuel heater relay control circuit is shorted to voltage for greater than 1 s.

OBDII Code P2689 GMC - Fuel Heater Relay Control Circuit High Voltage - AutoCodes.com — P2689 GMC Code - Fuel Heater Relay Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P2689 GMC?

Faulty Fuel Supply Heater
Fuel Supply Heater harness is open or shorted
Fuel Supply Heater circuit poor electrical connection

How to Fix the DTC P2689 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 P2689 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.

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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 P2689 GMC Code

1. What are the common symptoms of OBDII code P2689 GMC (Fuel Heater Relay Control Circuit High Voltage)?

The common symptoms include poor engine performance, reduced fuel efficiency, and the illumination of the Check Engine light on the dashboard.

2. What are the possible causes of OBDII code P2689 GMC?

Possible causes include a faulty fuel heater relay, damaged wiring or connectors in the fuel heater circuit, a defective fuel heater, or a problem with the powertrain control module (PCM).

3. How serious is OBDII code P2689 GMC?

While this code may not cause immediate harm to the vehicle, it can lead to reduced fuel efficiency and engine performance if left unresolved. It is recommended to address the issue promptly to prevent further damage.

4. How can I diagnose OBDII code P2689 GMC?

Diagnosis typically involves using an OBDII scanner to retrieve the code, inspecting the fuel heater relay and related components for any visible damage, and testing the circuit for proper voltage and continuity.

5. How can I repair OBDII code P2689 GMC?

Repairing this code often involves replacing the faulty fuel heater relay, repairing or replacing damaged wiring or connectors, testing and possibly replacing the fuel heater, and clearing the code from the PCM.

6. Can I drive my vehicle with OBDII code P2689 GMC?

It is generally not recommended to drive your vehicle with this code present, as it can lead to further issues with engine performance and fuel efficiency. It is best to address the problem as soon as possible.

7. How much does it cost to repair OBDII code P2689 GMC?

The cost of repair can vary depending on the specific cause of the code and the labor rates in your area. Replacing a fuel heater relay or repairing wiring may cost a few hundred dollars, while more extensive repairs could be more expensive.

8. Can OBDII code P2689 GMC be triggered by a loose gas cap?

While a loose gas cap typically triggers evaporative emission codes, it is not likely to cause code P2689 related to the fuel heater relay control circuit.

9. Will resetting the Check Engine light resolve OBDII code P2689 GMC?

Resetting the Check Engine light may temporarily clear the code, but it will likely return if the underlying issue is not addressed. It is important to diagnose and repair the cause of the code to prevent further problems.

10. How long does it take to repair OBDII code P2689 GMC?

The repair time can vary depending on the exact cause of the code and the complexity of the repair. Simple fixes like replacing a relay may take less than an hour, while more involved repairs could take several hours or more.