The P1487 code is a manufacturer-specific powertrain code. Because it is manufacturer-specific, its exact definition depends entirely on the vehicle application, most commonly relating to the EGR system on Mazda and Kia vehicles, or the radiator cooling fan circuit on Chrysler, Dodge, Jeep, and Honda applications.
This code identifies a detected electrical circuit condition or system check failure, not necessarily a failed component. Proper diagnosis requires verifying the exact factory definition for your vehicle and testing the relevant circuits.
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Key Takeaways
- The P1487 code is manufacturer-specific, typically indicating an EGR solenoid circuit fault or a high-speed radiator fan relay circuit issue.
- Possible causes include wiring faults, poor electrical connections, failed solenoids or relays, or module driver issues.
- Symptoms depend on the application and may include an illuminated Check Engine Light, engine overheating, or reduced performance.
- Diagnosis requires confirming the exact factory definition and testing the specific circuit for opens, shorts, or excessive resistance.
- Repairs vary by application and may involve wiring repair, solenoid replacement, or relay replacement.
P1487 Code Description and Implications
P1487 is a manufacturer-specific code. Its exact definition depends entirely on the vehicle application.
Some Mazda and Kia applications: The code indicates an “EGR Boost Sensor Solenoid Valve Circuit Malfunction,” meaning the Powertrain Control Module (PCM) has detected an open or short circuit in the solenoid that controls vacuum to the EGR system.
Certain Chrysler, Dodge, Jeep, and Honda applications: The code typically indicates a “High Speed Radiator Fan Control Relay Circuit” fault, where the PCM detects an electrical issue preventing the high-speed cooling fan from engaging.
Some other applications: The code may relate to an EGR check solenoid or an evaporative emissions (EVAP) vent circuit fault. Because definitions vary, verifying the exact factory service information is mandatory.
Common Causes of the P1487 Code
Several conditions can trigger this manufacturer-specific malfunction code. Identifying the exact cause requires electrical testing of the specific circuit.
- For EGR solenoid applications: An internally failed or shorted EGR boost sensor solenoid valve.
- For cooling fan applications: A failed high-speed radiator fan control relay.
- Broken, chafed, or shorted wiring in the control circuit between the PCM and the solenoid or relay.
- Corroded, loose, or contaminated electrical connectors at the component or the PCM.
- Poor ground connections for the solenoid, relay, or cooling fan motor.
- Faulty PCM or internal module driver issue (rare, usually only after circuit verification).
Symptoms Associated With P1487
Symptoms vary significantly depending on which system the code monitors on your specific vehicle.
- Illuminated Check Engine Light.
- On EGR applications: Rough idle, hesitation, or decreased fuel efficiency due to improper exhaust gas recirculation.
- On cooling fan applications: Engine overheating, especially at idle or low speeds, because the high-speed fan cannot engage.
- On some applications, the vehicle may enter a reduced power or limp mode to protect the engine.
Diagnosing the P1487 Trouble Code
Diagnosis must begin by confirming the exact factory definition for your specific make and model.
- Verify the exact manufacturer definition and locate the wiring diagram for the specific solenoid or relay circuit.
- Visually inspect the wiring harness and connectors at the component and the PCM, looking for broken wires, chafing, or corrosion.
- Use a digital multimeter to measure the resistance of the solenoid or relay coil and compare it to manufacturer specifications.
- Check the control circuit for continuity and verify there are no shorts to ground or shorts to voltage.
- Use a scan tool with bidirectional controls to command the solenoid or relay on and off while monitoring the circuit voltage or listening for the component click.
Repairing the P1487 Issue
Repairs depend entirely on the confirmed root cause of the circuit malfunction.
- If wiring damage or an open/short circuit is found, repair or replace the affected harness sections and secure the routing.
- Clean or replace corroded connectors to restore proper electrical contact and circuit integrity.
- If the EGR boost sensor solenoid fails electrical testing, replace it using a component meeting the correct vehicle specification.
- If the high-speed radiator fan relay fails testing, replace the relay and verify the cooling fan operates at both low and high speeds.
- If testing confirms the PCM driver is faulty and all external circuits are intact, follow the manufacturer procedure for module replacement.
Cost Considerations for P1487 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Replacing a standard relay or an externally mounted solenoid is generally less expensive than diagnosing and replacing a PCM or repairing a wiring harness buried deep within the engine bay.
Prevention Strategies for Future Occurrences
While electrical failures are not always preventable, some practices can reduce the risk of circuit issues.
- Inspecting exposed wiring and connectors can help identify developing damage from heat exposure, chafing, or rodent activity.
- Keeping electrical connections clean and sealed helps prevent moisture intrusion and corrosion in harsh climates.
- Ensuring proper routing of the wiring harness during previous engine repairs prevents the wires from resting on hot exhaust components.
Troubleshooting Tips and Best Practices
Always consult the exact manufacturer service information for your vehicle’s wiring diagram and pinout values.
- Do not assume a solenoid or relay is faulty simply because the code points to its circuit; wiring damage and connector corrosion are frequently the actual cause.
- For cooling fan applications, check for related fan motor codes or temperature sensor codes that may indicate a broader cooling system issue.
- Verify technical service bulletins for your specific make and model, as some manufacturers issue updated wiring harnesses or revised relays for recurring circuit faults.
More OBD-II Codes
| P1486 | P1485 | P1484 | P1483 |
| P1482 | P1481 | P1488 | P1491 |
| P1498 | P1475 | P1476 | P1477 |
| P1403 | P1404 | P1405 | P1406 |
| P0480 | P0481 | P0690 | P0691 |
| P0420 | P0430 | P0171 | P0174 |
Frequently Asked Questions
Is the P1487 code generic or manufacturer-specific?
No. P1487 is a manufacturer-specific code. Its exact definition varies by vehicle make, commonly indicating an EGR solenoid circuit fault or a radiator fan relay issue.
Can I drive my car with a P1487 code?
It depends on the application. If the code relates to the radiator cooling fan, driving the vehicle may cause severe engine overheating. If it relates to the EGR system, drivability may be affected.
Will a bad relay cause a P1487 code?
Yes. On applications where P1487 monitors the high-speed radiator fan control relay, a failed relay coil or internal contacts will trigger this circuit malfunction code.
Can a vacuum leak trigger the P1487 code?
Typically no. P1487 is an electrical circuit code for a solenoid or relay. However, a disconnected vacuum hose on the EGR solenoid may cause secondary performance codes.
Will a P1487 code cause an emissions test failure?
Yes. Any code that illuminates the Check Engine Light will typically cause an automatic failure during an OBD-II emissions inspection until the underlying issue is diagnosed and repaired.
What Should You Do About the P1487 Code?
Confirm the exact factory definition for your specific vehicle application. Follow the applicable manufacturer diagnostic procedure to test the relevant system circuits, solenoids, or relays.
Repair or replace the confirmed failed component or fix the identified wiring fault, then retest the system to ensure proper operation.
