Need a P04A1 diagnosis? Trust our experts.
Oops! We got lost!
Your location cannot be detected. Please enter your zipcode for nearby shops.
P04A1 Severity
Once the vehicle's onboard system no longer detects the issue, most codes will disappear on their own. If your vehicle still has this code, however, it should be properly diagnosed to avoid a more serious problem.
For a proper diagnosis, RepairPal Certified shops have the equipment, tools, and expertise.
Moderate severity codes might not threaten the vehicle's safety or functionality immediately, but you should still get it diagnosed within a reasonable time frame to keep your car running well.
The Exhaust Pressure Control Valve controls exhaust back pressure during engine warmup. If the engine control module (PCM) determines there is an incorrect signal from the Exhaust Pressure Control Valve, the PCM will set code P04A1.
RepairPal Car Genius™ is a free resource for vehicle owners seeking advice on maintenance, auto repair, shop inquiries, estimates, and finding a trustworthy repair shop in your area.
Call us at 877-913-1554
Available 9am – 6pm ET Monday through Friday
OBD-II Code Powertrain Control Module (PCM) failure is defined as a Exhaust Pressure Control Valve "B" Low
The Exhaust Pressure Control Valve controls exhaust back pressure during engine warmup. If the engine control module (PCM) determines there is an incorrect signal from the Exhaust Pressure Control Valve, the PCM will set code P04A1.