What is OBD2 Code P1487 on a Dodge?
When your Dodge’s check engine light illuminates and a scan tool reveals code P1487, it indicates a specific fault within the Evaporative Emission Control (EVAP) system. This Diagnostic Trouble Code (DTC) is defined as “EVAP Leak Detection Pump Heater Circuit”. Primarily affecting Dodge, Chrysler, and Jeep vehicles (often those with the 3.3L, 3.8L, or 4.0L engines), this code points to an electrical problem with the internal heater element of the Leak Detection Pump (LDP). The LDP is a critical component that helps the Powertrain Control Module (PCM) monitor the EVAP system for vacuum leaks. A malfunctioning heater can prevent the system from performing its self-tests, potentially allowing fuel vapors to escape and causing a failed emissions inspection.
Symptoms and Common Causes of P1487
Unlike codes related to engine misfires, P1487 may not cause dramatic drivability issues. However, ignoring it can lead to increased emissions and a non-functional EVAP monitor.
Primary Symptoms of Code P1487
- Illuminated Check Engine Light (MIL): The most common and often the only noticeable symptom.
- Failed Emissions Test: The EVAP monitor will likely be “not ready,” causing an automatic failure in states with mandatory testing.
- Possible Rough Idle (Less Common): In some cases, a significant EVAP system fault can slightly affect engine vacuum and idle quality.
- No Other Drivability Problems: The vehicle typically runs, starts, and accelerates normally.
Root Causes of the P1487 Fault
- Failed Leak Detection Pump (LDP): The internal heater element has burned out or shorted. This is the most frequent cause.
- Damaged Wiring or Connectors: Corrosion, chafing, or rodent damage to the wiring harness supplying power or ground to the LDP heater.
- Blown Fuse: A fuse dedicated to the EVAP system or the LDP heater circuit may be blown.
- Poor Electrical Ground: A corroded or loose ground connection for the LDP or PCM.
- Faulty Powertrain Control Module (PCM): Rare, but a malfunction within the PCM itself could prevent it from controlling the heater circuit.
Step-by-Step Diagnostic Procedure for P1487
Proper diagnosis is key to avoiding unnecessary part replacement. Follow this systematic approach. Warning: Always disconnect the battery before performing electrical tests for safety.
Step 1: Preliminary Inspection
Begin with a visual check. Locate the Leak Detection Pump (usually near the fuel tank or in the rear quarter panel). Inspect the wiring harness and connector for obvious damage, corrosion, or disconnection. Check the relevant fuse (often in the Power Distribution Center under the hood).
Step 2: Electrical Testing of the LDP Heater
Using a digital multimeter (DMM), disconnect the electrical connector from the LDP. Measure the resistance across the heater terminals on the pump itself. Specifications vary, but a reading of open circuit (infinite ohms) or short circuit (near zero ohms) confirms a faulty LDP heater. A typical good reading might be between 10 and 30 ohms.
Step 3: Checking Power and Ground Circuits
With the connector disconnected and the ignition ON, back-probe the vehicle-side connector. Check for battery voltage (typically 12V) on the power wire. If voltage is missing, trace the circuit back to the fuse. Next, check the ground circuit for continuity to a known good ground.
Step 4: Using a Bi-Directional Scanner
An advanced scan tool can command the LDP heater on and off. If the tool can activate the heater and you can measure voltage/current change at the connector, but the code returns, the pump is likely bad. If the scanner cannot command the heater, the issue is in the control circuit or PCM.
Repair Solutions and Replacement Guide
Once the faulty component is identified, proceed with the repair.
Replacing the Leak Detection Pump (LDP)
If testing confirms a failed LDP, replacement is necessary. The pump is typically held by bolts or clips. Important: You must also replace the LDP filter (a small foam filter) located on or near the pump. A clogged filter is a common contributor to pump failure. After replacement, clear the codes with your scanner and perform an EVAP monitor drive cycle to ensure the repair was successful.
Repairing Wiring Harness Issues
For damaged wires, solder and heat-shrink tubing provide the most reliable repair. Never use twist-on connectors in automotive environments. Ensure all connections are clean, tight, and protected from the elements.
Clearing the Code and Completing the Drive Cycle
After repairs, clear the P1487 code from the PCM’s memory. The check engine light will turn off, but the EVAP monitor will be “not ready.” To set the monitor and prevent an emissions test failure, you must complete a specific drive cycle. This often involves a mix of highway and city driving with a cool start and a specific fuel tank level (between 1/4 and 3/4 full). Consult your vehicle’s service manual for the exact procedure.
Conclusion: Ensuring a Lasting Fix
Code P1487 on your Dodge is a specific electrical fault within a critical emissions system. While it may not strand you on the side of the road, it requires attention to pass emissions tests and ensure your vehicle operates as designed. A methodical diagnosis—starting with simple visual checks and progressing to electrical tests—will pinpoint the issue, whether it’s a failed Leak Detection Pump, a blown fuse, or damaged wiring. Always remember to replace the associated LDP filter during pump replacement to prevent a quick recurrence. By addressing P1487 promptly and correctly, you restore your Dodge’s EVAP system integrity, turn off the check engine light, and ensure it meets environmental standards.