Chrysler P1403 Trouble Code: Expert Diagnosis, Causes, and Solutions

The engine light illuminating on your dashboard is always a cause for concern. When the diagnostic scanner reveals the Chrysler P1403 code, it is crucial to understand its meaning to act effectively. This specific trouble code is related to the Evaporative Emission Control System (EVAP system), more precisely to the Fuel Vapor Reduction System Flow Meter. It generally indicates a problem with insufficient flow or a malfunction of the system’s solenoid control valve. Ignoring this code can, in some cases, affect engine performance and increase polluting emissions. This article details everything you need to know to diagnose and resolve this issue knowledgeably.

What is the P1403 trouble code on a Chrysler?

The P1403 code is a generic code related to the engine control system. On vehicles from the Chrysler group (Dodge, Jeep, Ram), it specifically relates to “Fuel Vapor Reduction System Flow Meter – Insufficient Flow Detected.” Simply put, the engine computer (PCM) continuously monitors the flow of fuel vapors that are recycled and burned in the engine. When the PCM detects that the actual flow is lower than the expected value during system tests, it records the Chrysler P1403 code and illuminates the check engine light. This system is essential for complying with anti-pollution standards by preventing hydrocarbon evaporation into the atmosphere.

Symptoms associated with the P1403 code

Unlike other faults, the P1403 code is not always accompanied by visible and drastic symptoms. The vehicle may seem to be running perfectly normally. However, some signs may appear:

• The check engine light is permanently on.
• A slight drop in performance or hesitation may be noticeable, especially during acceleration.
• A slight increase in fuel consumption may occur.
• During an emissions test, the vehicle may fail due to excessive emissions.
• In the worst case, a gasoline odor may be noticeable near the vehicle.

Main causes of the P1403 fault

Several elements can be the origin of this code. A methodical diagnosis is necessary to identify the root cause without replacing parts unnecessarily.

• Faulty Solenoid Control Valve (EVAP Purge Valve): This is the most common cause. This valve, controlled by the PCM, can stick in the open or closed position, or become sluggish, preventing the correct flow of vapors.
• Clogged or Leaking EVAP Lines: A hose in the EVAP system can be clogged by debris, bent, or have a leak, disrupting pressure and flow.
• Electrical Problem: A bad connector, a cut wire, or corrosion on the purge valve harness can distort the signal sent to the PCM.
• Faulty or Loose Gas Cap: A cracked or missing cap prevents the system from pressurizing/creating a vacuum correctly.
• PCM Module Fault: Although rare, an internal failure of the computer itself may be the cause.

Diagnostic procedure and solutions

Before replacing anything, a thorough check is essential. It is highly recommended to use a scan tool capable of commanding actuators for effective diagnosis.

Step 1: Visual Inspection
Start with a thorough inspection of the entire EVAP system. Check the condition of all hoses and lines for cracks, disconnections, or signs of wear. Ensure the gas cap is tight and in good condition.

Step 2: Purge Valve Test
The purge valve is often located near the tank or on the throttle body. Disconnect its electrical connector and its two hoses. Using a multimeter, check the resistance of the solenoid coil (refer to manufacturer specifications, usually between 20 and 50 Ohms). Then, apply 12 volts directly to the valve terminals; you should hear a distinct click indicating it opens. Without voltage, it should be closed (you should not be able to blow through it). If it does not respond, it must be replaced.

Step 3: Electrical Circuit Check
With the connector unplugged and the ignition on, check for the presence of supply voltage (usually 12V) on one pin of the connector. Also check the integrity of the ground wire and the control wire from the PCM.

Step 4: Line Cleaning
If an obstruction is suspected, blow compressed air through the lines (after disconnecting them) to clear them.

After any repair, clear the trouble code with your scanner and perform a drive cycle to ensure the light does not come back on. If the Chrysler P1403 code reappears after replacing the valve, it is advisable to consult a professional mechanic with advanced diagnostic tools to test the system pressure.