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P0688 Chevrolet Code - Electronic Control Module Power Relay Sense Circuit/Open

Quick Answer

The P0688 code in Chevrolet vehicles indicates a problem with the Electronic Control Module (ECM) power relay sense circuit, specifically an open circuit. Common causes include Faulty ECM power relay, Damaged wiring or connectors in the power relay sense circuit, Corrosion or poor connections in the circuit. 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
P0688 Chevrolet indicates Electronic Control Module Power Relay Sense Circuit/Open.
Common causes
Common causes include Faulty ECM power relay, Damaged wiring or connectors in the power relay sense circuit, Corrosion or poor connections in the circuit.
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 Sep 11, 2024
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Code P0688 Chevrolet Description

The P0688 code in Chevrolet vehicles indicates a problem with the Electronic Control Module (ECM) power relay sense circuit, specifically an open circuit. The ECM power relay is responsible for providing power to the ECM, which is the brain of the vehicle's engine management system. The ECM controls various functions such as fuel injection, ignition timing, and emissions systems, making it a critical component for the vehicle's overall performance.

OBDII Code P0688 Chevrolet - Electronic Control Module Power Relay Sense Circuit/Open
P0688 Chevrolet Code - Electronic Control Module Power Relay Sense Circuit/Open

Common Causes of P0688 Chevrolet

  1. Faulty ECM power relay
  2. Damaged wiring or connectors in the power relay sense circuit
  3. Corrosion or poor connections in the circuit
  4. Defective ECM

Symptoms of P0688 Chevrolet

  1. Engine misfires or runs rough
  2. Poor fuel economy
  3. Vehicle stalls or struggles to start
  4. Check Engine Light illuminated
  5. Loss of power or acceleration

How to Fix P0688 Chevrolet

  1. Use a diagnostic scanner to retrieve the fault code and confirm the issue.
  2. Inspect the ECM power relay and related wiring for any visible damage or corrosion. Replace any faulty components.
  3. Test the power relay sense circuit for continuity to identify any open circuits.
  4. Clear the fault code from the ECM memory and test drive the vehicle to ensure the issue is resolved.
  5. If the problem persists, further diagnostic testing may be required to determine the exact cause of the fault.

Cost to Fix P0688 Chevrolet

The cost to repair a P0688 code in a Chevrolet vehicle can vary depending on the specific cause of the issue. On average, the parts for this repair, including a new ECM power relay or wiring harness, can range from $50 to $200. Labor costs at an auto repair shop typically range from $100 to $300, depending on the hourly rate and the complexity of the repair. Overall, the total repair cost for addressing a P0688 code in a Chevrolet vehicle can range from $150 to $500. It is advisable to consult with a local auto repair shop for a more accurate estimate based on your vehicle's make and model.

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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 P0688 Chevrolet Code

1. What are the common symptoms of OBDII code P0688 in a Chevrolet vehicle?

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

2. What does the OBDII code P0688 Chevrolet indicate?

- The code indicates a problem with the Electronic Control Module (ECM) power relay sense circuit, specifically an open circuit.

3. What are some possible causes of the P0688 code in a Chevrolet?

- Possible causes include a faulty ECM power relay, damaged wiring or connectors in the relay circuit, a blown fuse, or a malfunctioning ECM.

4. How can I diagnose the cause of the P0688 code in my Chevrolet vehicle?

- Diagnosis typically involves checking the ECM power relay, inspecting the wiring and connectors for damage, testing the relay circuit for continuity, and verifying proper voltage levels.

5. Can I drive my Chevrolet with the P0688 code present?

- It is not recommended to drive the vehicle with the P0688 code as it can lead to further damage to the ECM and other components. It's best to address the issue promptly.

6. How can I repair the Electronic Control Module power relay sense circuit/open issue in my Chevrolet?

- Repairs may involve replacing the faulty ECM power relay, repairing or replacing damaged wiring or connectors, and resetting the trouble code with an OBDII scanner.

7. Are there any specific tips for preventing the recurrence of the P0688 code in a Chevrolet?

- Regularly inspecting and maintaining the ECM power relay, wiring, and connectors can help prevent the recurrence of the P0688 code. It's also important to address any electrical issues promptly.

8. Can a DIY enthusiast fix the P0688 code issue in a Chevrolet?

- Depending on their skill level and access to tools, a DIY enthusiast may be able to diagnose and repair the P0688 code. However, it's recommended to consult a professional for complex electrical issues.

9. How much does it typically cost to repair the P0688 code in a Chevrolet at a repair shop?

- The cost of repairs for the P0688 code can vary depending on the root cause of the issue, the labor rates of the repair shop, and the cost of replacement parts. It's best to get a quote from a reputable shop.

10. Is it possible for the P0688 code to trigger other trouble codes in a Chevrolet?

- Yes, the P0688 code can sometimes trigger related codes such as P0689 (ECM/PCM Power Relay Sense Circuit Low) or P0690 (ECM/PCM Power Relay Sense Circuit High). It's important to address all relevant codes during diagnosis and repair.

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