Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car has a special system that helps reduce pollution. This system needs to know how much pressure is in it, kind of like checking if a balloon is full. Right now, the car thinks the pressure is too high, like the balloon is about to pop.
The P204D code indicates that the Engine Control Module (ECM) has detected a high voltage signal from the reductant pressure sensor circuit, suggesting that the pressure is higher than expected.
The reductant pressure sensor is part of the Selective Catalytic Reduction (SCR) system, which reduces emissions by injecting a urea-based solution into the exhaust. The sensor monitors the pressure of this solution. A 'high' circuit condition indicates that the sensor is reporting a higher-than-normal pressure, which could be due to a sensor fault, wiring issue, or actual pressure problem.
• Check Engine Light is on
• Possible reduction in engine performance
• Increased emissions
• Faulty reductant pressure sensor
• Wiring issues such as shorts or open circuits
• Malfunctioning SCR system components
SCR: Selective Catalytic Reduction, a system that reduces emissions by injecting a urea-based solution into the exhaust.
ECM: Engine Control Module, the computer that controls the engine and monitors emissions systems.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Test the reductant pressure sensor for proper operation.
• Replace the faulty reductant pressure sensor.
• Repair or replace damaged wiring or connectors.
• Inspect and repair other SCR system components if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 1500
• Regularly inspect and maintain the SCR system.
• Ensure proper fluid levels in the reductant tank.
• Use high-quality reductant fluid.
Sensor Issue
• Do not ignore the Check Engine Light.
• Consult a professional mechanic if unsure.
• Avoid driving long distances until fixed.
Check your vehicle's warranty for emissions-related components, as they may be covered for an extended period.
The P204D code has been more common in vehicles with advanced emission control systems introduced in the past decade.
Moderate – While the vehicle may still run, emissions performance is compromised and should be addressed soon.
Driving with a malfunctioning emissions system may violate environmental regulations and contribute to pollution.
• Engine running
• Vehicle in closed-loop operation
The reductant pressure sensor is typically located near the reductant tank or along the reductant line in the SCR system.
Q: Can I drive with a P204D code?
A: It's possible to drive short distances, but it's recommended to fix the issue soon to avoid increased emissions.
Q: What happens if I ignore the P204D code?
A: Ignoring the code can lead to increased emissions and potential damage to the SCR system.
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