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Inspect fuses
To fix a "Check Ign Fuse" or "Maintenance Required" message on a 2015 Volvo VNL with a D13 engine, inspect the main interior fuse and relay center located behind the upper dash panel on the passenger side. [1, 2] ## How to Check and Resolve the Issue * Locate the Panel: Open the passenger side and remove the upper dash panel to access the main fuse and relay board. [1] * Read the Decal: Flip the removed panel cover over to view the decal map showing each fuse number, label, and amperage size. [1] * Inspect the Ignition Fuse: Find the fuse labeled for ignition (IGN or IGN PWR) or key switch power. Pull it out using the fuse tool located in the bottom right of the panel. [1, 3] * Look for Damage: Replace any burned-out or blown fuse with one of the exact same amperage rating. [4, 5] * Check for Shorts: If the new fuse blows immediately when you turn the key, look for a short-to-ground in the under-dash wiring harness, ignition switch, or engine control unit (ECU) connections. [6, 7] * Inspect Battery Connections: Clean and check the main power switch and battery cables, as loose or corroded battery terminals can trigger false ECU maintenance warnings and power drops. Since your dashboard lights are turning on but you are getting the "Check Ign Fuse" message, your main dash power is active, but the Engine Control Module (ECM) wake-up circuit is missing its 12V key-switch signal. [1] Because you confirmed you've already pulled the ignition fuses inside the cab, the problem is most likely outside the cab or hidden in a secondary fuse holder. On a 2015 Volvo VNL D13, follow these targeted steps to isolate the issue: ## 1. Check the Inline Fuses by the Battery Box (Most Common) Volvo places a set of high-amperage inline fuses and standard mini-fuses directly inside or right next to the main battery box (usually under the driver’s side steps). * * Look for a small, black plastic weather-sealed fuse holder or an inline block branching off the positive battery cables. * These fuses supply unswitched direct power straight to the ECM. If one of these corrodes, gets wet, or blows, the dash will light up normally, but the ECM stays "dead," forcing the dash to display "Check Ign Fuse" or "Maintenance Required". [1, 2] * ## 2. Check the Engine Compartment Fuse Box Open the hood and locate the secondary electrical distribution box on the driver’s side firewall or near the steering column. * * Use a 12V test light or a multimeter to check the fuses labeled EMS (Engine Management System) or ECM. * Even if the fuse looks good visually, use a meter to test for continuity (ohms); sometimes micro-cracks inside the fuse element are impossible to see. [2, 3] * ## 3. Check the Ignition Switch Pins Since your dash lights power up, the accessory contact inside the ignition cylinder is functional, but the ignition start/crank contact may be failing. [4] * * Unplug the harness from the back of the physical key ignition switch. * Inspect the connector pins for signs of green corrosion or melting/burnt plastic. A loose contact terminal inside the plastic plug will cause a major voltage drop, tricking the computer into thinking a fuse is blown. [5, 6, 7] * ## 4. Test the Main Ignition Relay If you haven't swapped the physical relay yet, find the Ignition Relay in the passenger dash panel. Swap it with an identical, non-critical relay (like the horn or marker lights). If the relay internal contacts are burnt or stuck, it won't pass power even if the fuse preceding it is perfectly fine. [1, 8] To narrow this down to the exact wire or component: