What is the P0687 Fault-Error Code?
The P0687 Fault-Error Code typically means "ECM/PCM Power Relay Control Circuit High." This trouble code indicates that a high voltage has been detected in the power relay control circuit for the vehicle's engine control module (ECM) or power control module (PCM).
The ECM or PCM represents the vehicle's main control computer. These modules manage the vehicle's engine functions, process data from sensors, and optimize the engine's performance. The power relay is a key component that provides power to the ECM or PCM.
The P0687 trouble code means that the ECM or PCM is not receiving enough power or control. This can affect how the vehicle's engine operates and cause a variety of engine problems.
What are the symptoms of the P0687 Fault-Error Code?
Symptoms of P0687 Fault-Error Code may include:
Engine Not Starting Problem: When a high voltage is detected in the power relay control circuit of the ECM or PCM, the vehicle will not start or the engine may cut out during operation. This may occur as the engine being unresponsive or not starting at all when the driver attempts to start the vehicle.
Abnormal Changes in Engine Performance: A high voltage in the power relay control circuit may affect the engine performance of the ECM or PCM. This may cause the engine to run erratically, lose power, or have choppy acceleration. During vehicle driving, attention should be paid to any erratic or unstable engine operation.
Decreased Fuel Economy: Improper operation of the ECM or PCM can result in suboptimal adjustment of the fuel-air mixture. This can lead to decreased fuel efficiency, which can cause the vehicle to consume more fuel.
Malfunction Light On: A power relay control circuit high voltage fault in the ECM or PCM will usually cause a malfunction light to come on on your vehicle. This light is a warning sign that there is a problem with the vehicle.
Other Electrical Issues: A high voltage in the power relay control circuit can also affect other electrical systems in the vehicle. This can cause malfunctions or irregularities in the headlights, air conditioning system or other electrical components.
What Could Be the Causes of the P0687 Fault-Error Code?
Possible causes of P0687 Fault-Error Code could be:
Power Relay Failure: The vehicle's power relay that feeds the ECM or PCM may be faulty. An internal fault in the relay or a problem such as worn contacts may cause the relay to provide a high voltage or excessive power flow.
Wiring Problems: There may be a problem with the wiring between the power relay and the ECM or PCM. Loose or broken wires can cause high voltage or excessive power flow.
Short Circuit in Power Relay Control Circuit: A short circuit may occur in the power relay control circuit. This may cause the power flow to increase uncontrollably and high voltage may be detected.
Open Circuit in Power Relay Control Circuit: An open circuit may exist in the power relay control circuit. This can cause the power flow to be interrupted and then reconnected, which can result in high voltage being detected.
ECM or PCM Malfunction: In rare cases, there may be an internal malfunction in the ECM or PCM. In this case, there may be a problem with the relay or control circuit that allows these modules to receive power.
Power Supply Issues: A general power supply problem in the vehicle's electrical system can also cause the P0687 error. This could be due to high voltage from the vehicle's battery or alternator.
What Steps Should Be Followed to Resolve the P0687 Fault-Error Code?
To resolve the P0687 fault/error code, the following steps can be followed:
Checking the Power Relay and Connections: As a first step, the vehicle's power relay and connection points should be examined. The power relay should be checked and any signs of wear, burning or corrosion should be checked. The wiring between the relay and the ECM or PCM should also be checked. Any loose, broken or corroded connections should be corrected.
Testing the Power Relay and Control Circuit: Using a multimeter or suitable electrical tester, test the power relay and control circuit. Verify that the power relay is operating properly and that the circuits are conducting properly.
Power Relay or Control Circuit Replacement: If a fault is found in the power relay or control circuit, these components should be replaced. An authorized service center or auto repair shop can provide and install the appropriate parts.
Testing the ECM or PCM: If other steps fail to resolve the issue, the ECM or PCM may need to be tested. This can be a more involved process and usually requires a professional repair. If a fault is detected in these modules, they may need to be repaired or replaced.
Electrical Problem Repair: If other electrical problems are found in the power relay control circuit, these problems should also be corrected. If shorts, opens, or other wiring problems are found, they should be corrected.
Test and Verify the Vehicle: After all procedures are completed, the vehicle should be taken for a test drive. This is important to ensure that the vehicle's engine is operating normally and the fault light is not on.
What Are the Long-Term Effects of the P0687 Fault-Error Code?
Long-term effects of P0687 Fault-Error Code may include:
Reduced Engine Performance: When a high voltage is detected in the power relay control circuit, it can prevent the ECM or PCM from receiving proper power. This can cause a decrease in engine performance or loss of power. It can cause the engine to feel unresponsive or provide reduced acceleration.
Increased Electrical Problems: A high voltage power relay control circuit can also affect other electrical components of the vehicle. This can cause malfunctions or irregularities in the headlights, air conditioning system or other electrical components.
Power Supply Issues: A high voltage power relay control circuit could indicate a general power supply problem in the vehicle's electrical system, potentially affecting the battery, alternator, or other electrical components.
ECM or PCM Damage: A consistently high voltage power relay control circuit can overload or fail the ECM or PCM, which can negatively impact the long-term health of the electronic control systems in the vehicle and require costly repairs.
Safety Risk: A problem in the power relay control circuit could cause the vehicle to stop or fail to start unexpectedly. This could cause the driver to lose control or create dangerous situations, especially when in traffic or driving at high speeds.
For these reasons, it is important to quickly resolve the issue caused by the P0687 fault/error code. Such issues should not be ignored for the long-term performance, safety and cost of the vehicle. It is important to have the problem diagnosed and resolved by a professional mechanic or service.
Comments