AutoCodes – Saturn – P0688 Saturn

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

Quick Answer

The powertrain relay is a normally open relay. Common causes include Weak battery, Low voltage while cranking, Faulty Engine Control Module (ECM) power relay. 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 Saturn indicates Electronic Control Module Power Relay Sense Circuit/Open.
Common causes: Common causes include Weak battery, Low voltage while cranking, Faulty Engine Control Module (ECM) power relay.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 1,514

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 May 15, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0688 Saturn Description

The powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The Engine Control Module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an Output Driver Module (ODM). The ODM output control is configured to operate as a low side driver for the powertrain relay. The ODM for the powertrain relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. When the ECM commands the powertrain relay ON, ignition 1 voltage is supplied to the ECM, and to several additional circuits.

OBDII Code P0688 Saturn - Electronic Control Module Power Relay Sense Circuit/Open - AutoCodes.com — P0688 Saturn Code - Electronic Control Module Power Relay Sense Circuit/Open

What does this mean?

What are the Possible Causes of the DTC P0688 Saturn?

Weak battery
Low voltage while cranking
Faulty Engine Control Module (ECM) power relay
ECM power relay harness is open or shorted
ECM power relay circuit poor electrical connection
Blown ECM fuse
Faulty ECM

How to Fix the DTC P0688 Saturn?

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 P0688 Saturn 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 P0688 Saturn code?

Need more information on how to fix the P0688 Saturn code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0688 Saturn code diagnosed by a professional: Find a repair shop in your area

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 Saturn Code

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

- Common symptoms include the check engine light being illuminated, engine stalling or not starting, and loss of power while driving.

2. What does the OBDII code P0688 for a Saturn indicate?

- This 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 Saturn?

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

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

- Diagnosing the P0688 code may involve checking the ECM power relay, inspecting the relay circuit for damaged wires or loose connections, and testing the ECM for proper function.

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

- It is not recommended to drive your vehicle with the P0688 code present, as it can lead to engine stalling or other issues that may compromise safety.

6. How serious is the P0688 code in a Saturn?

- The P0688 code can be serious as it affects the ECM power relay, which can impact the overall performance and drivability of the vehicle.

7. Is it safe to reset the OBDII code P0688 in my Saturn without fixing the underlying issue?

- It is not recommended to simply reset the code without addressing the underlying problem, as it may lead to recurring issues and potential safety hazards.

8. Can I repair the P0688 code in my Saturn myself, or should I take it to a professional mechanic?

- Depending on your experience and knowledge, you may be able to repair the P0688 code yourself by checking the relay circuit and replacing any faulty components. However, it is recommended to consult a professional mechanic for accurate diagnosis and repair.

9. What are some tips for preventing the OBDII code P0688 from recurring in my Saturn?

- To prevent the P0688 code from recurring, it is important to regularly inspect and maintain the ECM power relay, as well as ensure proper wiring connections and ECM function.

10. How much does it typically cost to repair the P0688 code in a Saturn?

- The cost of repairing the P0688 code in a Saturn can vary depending on the specific cause of the issue, but it may involve replacing the ECM power relay or repairing damaged wiring, with potential costs ranging from $100 to $500 or more.