Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car's computer isn't getting enough power because something might be wrong with the switch that turns it on.
The ECM/PCM power relay is responsible for supplying power to the engine control module (ECM) or powertrain control module (PCM). This code indicates that the relay is not sending the correct voltage signal back to the ECM/PCM.
The P0689 code is triggered when the ECM/PCM detects a low voltage signal from the power relay sense circuit. This could be due to a faulty relay, wiring issues, or a problem with the ECM/PCM itself. The relay is supposed to provide a specific voltage signal to confirm that it is functioning properly. If this signal is too low, the ECM/PCM cannot operate correctly.
• Engine may not start
• Check Engine Light illuminated
• Intermittent stalling
• Faulty ECM/PCM power relay
• Damaged or corroded wiring/connectors
• Faulty ECM/PCM
ECM: Engine Control Module
PCM: Powertrain Control Module
Relay: An electrical switch that opens and closes under the control of another electrical circuit
• Use a scan tool to verify the code.
• Inspect the ECM/PCM power relay and its connections.
• Check wiring and connectors for damage or corrosion.
• Replace the ECM/PCM power relay if faulty.
• Repair or replace damaged wiring/connectors.
• Replace the ECM/PCM if necessary.
• OBD-II scan tool
• Multimeter
• Screwdriver set
$100 - $300
Moderate
• Chevrolet Silverado
• Ford F-150
• Honda Accord
• Regularly inspect electrical connections.
• Keep the battery and charging system in good condition.
• Avoid moisture exposure to electronic components.
Electrical Issue
• Have the vehicle inspected by a professional if the engine won't start.
• Do not ignore the Check Engine Light.
Check with your vehicle manufacturer for warranty coverage on electronic components.
This code has been associated with electrical issues in vehicles with complex electronic systems.
High – This issue can prevent the vehicle from starting or cause it to stall unexpectedly.
Driving with a malfunctioning ECM/PCM can lead to unsafe driving conditions.
• Vehicle in park or neutral
• Battery fully charged
The ECM/PCM power relay is typically located in the fuse box under the hood.
Q: Can I drive my car with a P0689 code?
A: It's not recommended as the car might stall or not start at all.
Q: How can I reset the Check Engine Light?
A: Fix the issue causing the code, then use an OBD-II scanner to clear the code.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.