Engine-CodesJeep – P0687 Jeep

P0687 Jeep Code - Engine Control Module Power Relay Control Circuit High

Quick Answer

The P0687 code for Jeep vehicles refers to an issue with the Engine Control Module (ECM) power relay control circuit being detected as too high. Common causes include Faulty Power Relay: The power relay responsible for supplying power to the ECM may be faulty, causing high voltage readings, Wiring Issues: Corrosion, damage, or loose connections in the wiring harness connected to the ECM can lead to high voltage in the circuit, ECM Malfunction: In rare cases, the ECM itself may be malfunctioning, causing the power relay control circuit to register as high voltage. 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
P0687 Jeep indicates Engine Control Module Power Relay Control Circuit High.
Common causes
Common causes include Faulty Power Relay: The power relay responsible for supplying power to the ECM may be faulty, causing high voltage readings, Wiring Issues: Corrosion, damage, or loose connections in the wiring harness connected to the ECM can lead to high voltage in the circuit, ECM Malfunction: In rare cases, the ECM itself may be malfunctioning, causing the power relay control circuit to register as high voltage.
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.
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P0687 Jeep Description

The P0687 code for Jeep vehicles refers to an issue with the Engine Control Module (ECM) power relay control circuit being detected as too high. The ECM power relay is responsible for supplying power to the ECM, which in turn controls various engine functions such as fuel injection, ignition timing, and emissions systems. When this circuit is detected as having high voltage, it can lead to malfunctions in the ECM's ability to properly control the engine, resulting in poor performance, decreased fuel efficiency, and potentially even engine stalling.

OBDII Code P0687 Jeep - Engine Control Module Power Relay Control Circuit High
P0687 Jeep Code - Engine Control Module Power Relay Control Circuit High

Common Causes of P0687 Jeep

  1. Faulty Power Relay: The power relay responsible for supplying power to the ECM may be faulty, causing high voltage readings.
  2. Wiring Issues: Corrosion, damage, or loose connections in the wiring harness connected to the ECM can lead to high voltage in the circuit.
  3. ECM Malfunction: In rare cases, the ECM itself may be malfunctioning, causing the power relay control circuit to register as high voltage.
  4. Electrical Short: An electrical short in the circuit can also trigger this code.
  5. Battery Voltage Spikes: Sudden spikes in battery voltage can impact the ECM power relay control circuit.

Symptoms of P0687 Jeep

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the Check Engine Light on the vehicle's dashboard.
  2. Engine Performance Issues: The vehicle may experience rough idling, hesitation, or a lack of power during acceleration.
  3. Poor Fuel Efficiency: Due to the ECM not functioning properly, the vehicle may consume more fuel than usual.
  4. Engine Stalling: In severe cases, the engine may stall or fail to start altogether due to the ECM power relay control circuit issue.

How to Fix P0687 Jeep

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble code and perform a thorough inspection of the power relay, wiring, and ECM.
  2. Replace Power Relay: If the power relay is found to be faulty, replace it with a new relay following the manufacturer's recommendations.
  3. Repair Wiring: Address any wiring issues by repairing or replacing damaged or corroded wires in the circuit.
  4. Test ECM: Test the ECM to ensure it is functioning properly and not causing the high voltage in the power relay control circuit.
  5. Clear Codes: Clear the trouble code from the ECM's memory using the diagnostic scanner after completing the repairs to reset the system.

Cost to Fix P0687 Jeep

The cost of repairing the P0687 code on a Jeep vehicle can vary depending on the specific cause of the issue. On average, the parts required for this repair, such as a new power relay, can range from $50 to $150. Labor costs at an auto repair shop can add an additional $100 to $200, bringing the total repair cost to around $150 to $350. However, it's important to note that labor rates can vary significantly based on location, the vehicle's make and model, and the shop's hourly rates. It's advisable to contact local repair shops for a more accurate estimate based on individual circumstances.

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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 P0687 Jeep Code

1. What does the OBDII code P0687 mean on a Jeep?

P0687 indicates a high voltage issue in the Engine Control Module (ECM) power relay control circuit, meaning the ECM isn't receiving or controlling power properly.

2. What are the common symptoms of code P0687 in a Jeep?

Symptoms may include the engine not starting, stalling while driving, reduced performance, or the Check Engine Light illuminated.

3. What causes the P0687 code to appear on a Jeep?

Common causes include a faulty ECM power relay, damaged wiring or connectors in the power relay circuit, blown fuses, or, in rare cases, a malfunctioning ECM.

4. Can a blown fuse trigger the P0687 code on a Jeep?

Yes, a blown fuse in the ECM power relay circuit can cause the P0687 code by interrupting the power supply.

5. How do I diagnose the P0687 code on my Jeep?

Start by inspecting the ECM power relay, related wiring, and fuses for damage or loose connections. Use a multimeter to test for proper voltage and continuity.

6. Is a faulty ECM common when dealing with the P0687 code on a Jeep?

A faulty ECM is a less common cause but should be considered if the relay and wiring are in good condition.

7. Can I drive my Jeep with the P0687 code?

It is not recommended to drive with this code, as it can lead to stalling or prevent the engine from starting, posing safety risks.

8. How do I fix the P0687 code on a Jeep?

Repairs may involve replacing a defective ECM power relay, repairing or replacing damaged wiring, or addressing issues with blown fuses.

9. How much does it cost to fix the P0687 code on a Jeep?

Repair costs vary depending on the issue but can range from $50 for a new relay to $500 or more if the ECM needs replacement.

10. Can a dead battery cause the P0687 code on a Jeep?

A weak or dead battery is unlikely to directly cause this code but could contribute to electrical system issues. Always check the battery when diagnosing electrical problems.

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