Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the second pump that helps cool the air going into the engine isn't working right because it's running without enough liquid to cool it down.
The P15F4 code is triggered when the second charge air cooler coolant pump is detected to be running without sufficient coolant, which can lead to overheating and reduced efficiency.
The charge air cooler is a component that cools the air compressed by the turbocharger before it enters the engine. This cooling is necessary to increase the air density and improve engine performance. The coolant pump circulates coolant through the cooler, and a 'dry run' condition indicates that the pump is operating without adequate coolant, potentially causing overheating and damage to the pump or other components.
• Check engine light on
• Reduced engine performance
• Overheating engine
• Low coolant level
• Faulty coolant pump
• Blocked coolant lines
Coolant: A fluid used to transfer heat away from the engine.
Charge Air Cooler: A device that cools compressed air from the turbocharger before it enters the engine.
• Check coolant level and top up if necessary
• Inspect the coolant pump for proper operation
• Check for blockages in the coolant lines
• Refill coolant to the proper level
• Replace faulty coolant pump
• Clear blockages in the coolant system
• Coolant refill tool
• Multimeter
• Wrench set
$150 - $500
Moderate
• Audi A4
• Volkswagen Golf
• BMW 3 Series
• Regularly check coolant levels
• Inspect coolant system for leaks
• Schedule routine maintenance
Engine Performance
• Do not ignore the check engine light
• Have your vehicle inspected by a professional
• Avoid driving the vehicle if overheating occurs
Check your vehicle's warranty for coverage on cooling system components.
This code has been associated with vehicles using turbocharged engines where cooling efficiency is critical.
High – This issue can lead to engine overheating and potential damage if not addressed promptly.
Driving with a malfunctioning coolant pump can lead to engine damage and is unsafe.
• Engine running
• Coolant system pressurized
The charge air cooler coolant pump is typically located near the front of the engine bay, connected to the charge air cooler and radiator.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to engine overheating and significant damage.
Q: Can I drive my car with this code?
A: It is not recommended to drive with this code active, as it can cause engine damage.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.