Three factors are driving the price and demand for a "new" DF104 in 2024/2025.
With the ignition on, check voltage between CAN wires and ground.
To understand the hype, we need a history lesson. In the early 1970s, Renault’s motorsport division needed a weapon for Formula France and the burgeoning European Formula Renault series.
The DF104 was not your standard Cléon-Fonte engine found in a Renault 12. It was a bespoke 1.6-liter (1565cc) inline-four racing engine. Its party trick? A crossflow aluminum cylinder head designed by Gordini, fed by two twin-choke Weber carburetors.
In period, it produced approximately 150 to 170 horsepower—massive numbers for a 1.6L in 1973. It revved past 8,000 rpm like a chainsaw and weighed next to nothing. It powered iconic open-wheelers like the Martini MK16 and Alpine A364.
Modern Renault vehicles use a CAN Bus (Controller Area Network) to allow different computers (ECUs) to talk to each other. For example, the instrument cluster needs to talk to the engine to show RPM, and the ABS module needs to talk to the dashboard to show speed.
The CAN system uses two wires:
DF104 triggers when: There is a break in communication between two or more ECUs on the network. The "New" status on a diagnostic tool indicates that the fault is currently present or occurred in the most recent driving cycle and has not yet been cleared or resolved. renault df104 new
If the network is down, unplug major modules one by one while monitoring the network status.
The Renault DF104 "New" was a miracle of French engineering and a disaster of French marketing. It was too early, too expensive, and too reliant on a battery chemistry that hadn't been conquered.
Drive a modern Renault Megane E-Tech Electric today. Notice the silence, the instant torque, the regenerative braking. That is not new technology. That is the ghost of the DF104, finally exorcised.
The "New" was never new. It was merely first.
Spec Sheet (1975 Renault DF104 New)
The Renault DF104 fault code primarily indicates an electrical or communication error, though its specific meaning can vary depending on which control module is being scanned. In modern Renault vehicles, it is most commonly associated with CAN line communication errors or specific relay circuit faults. Primary Meanings of DF104
Airbag Module (CAN Communication Error): In newer models like the Renault Master or Captur, DF104 often signals a "CAN error communication". This means the airbag computer is having trouble talking to other systems in the car. Common causes include: Three factors are driving the price and demand
Water Intrusion: The airbag module can fail if water leaks into the cabin through door or windshield seals.
Wiring Issues: Chafed wires or bad connections, often from aftermarket modifications or previous repairs, can disrupt the CAN line.
Engine/Injection (Thermoplunger Relay 2): In diesel models (like the Clio or Megane), DF104 can specifically point to a fault in the Thermoplunger Relay No. 2 circuit. Thermoplungers are used to help heat the engine coolant quickly in cold weather. Common Symptoms
Dashboard Warning Lights: You will likely see the airbag warning light or the "Service" spanner light illuminated.
Message Prompts: The trip computer may display general messages such as "Check Airbag" or "Braking System Fault" if the communication error affects multiple safety systems. Recommended Troubleshooting Steps
Clear the Codes: Use a Renault-specific diagnostic tool like CAN CLIP to clear the code first; sometimes these are "ghost" faults caused by a temporary low battery voltage.
Inspect the Airbag Module: Check for signs of moisture or corrosion around the module (usually located behind the center console). DF104 triggers when: There is a break in
Check Wiring Integrity: Look for broken or pinched wires under the seats (for airbag issues) or in the engine fuse box (for relay issues).
Test the Battery: A weak battery is a frequent culprit for communication errors across the entire Renault CAN network. BRAKING FAULT Renault Error [SOLVED] Depleted Car Battery
Based on Renault technical service documentation, DF104 is a specific fault code related to the Multiplexed Network (CAN Bus).
It is important to clarify the terminology: In Renault's diagnostic system (like the Clip tool), "DF" stands for "Default Fault". Therefore, "DF104" does not mean a part is called "DF104"; it means the car's computer has detected a specific communication failure.
Here is the detailed content regarding the fault code DF104, often displayed as "Multiplexed network communication fault" or "Network communication fault (CAN)".
Forget the latest Megane E-Tech. A quiet revolution is taking place in garages across Europe. Enthusiasts aren't searching for the newest EV crossover; they are typing a curious string of characters into eBay and forums: Renault DF104 new.
But how can a engine codenamed in 1971 be "new"? The answer lies in a perfect storm of vintage motorsport eligibility, lightweight chassis, and a sudden glut of NOS (New Old Stock) parts.
The "New" model utilized the floor pan of the Renault 5 (the "Supercinq"’s predecessor) but with a critical modification: a reinforced central tunnel to house the 72-volt battery pack. The body was still fiberglass—chosen for lightness—but the front grille was redesigned to hide the new, more efficient cooling system for the motor controller. Visually, it looked like a Renault 4 that had been stung by a bee: upright, awkward, but unmistakably functional.