Some 2020-2022 Ford F-Super Duty trucks may exhibit a condition where the engine will not turn off and/or have various electrical symptoms including a dead battery, horn stays on and no crank/no start.
The ABS indicator may be on, with DTCs C0020 and U3003 stored in the ABS module.
This may be the result of water/moisture intrusion into the battery junction box (BJB). This may be related to the BJB cover not being installed completely, or broken cover tabs/locking fingers, allowing moisture to enter. Inspect the BJB. If damage is found, replace the BJB assembly and cover.
1. Remove the battery and battery tray.
2. Remove the BJB cover.
3. Loosen the two BJB connector bolts and remove the battery power cable nut. Disconnect the battery power cable from the BJB.
4. Release the BJB from the two locking tabs on each side of the BJB.
5. List the BJB to allow access to both BJB connectors. Disconnect both connectors and remove the BJB.
6. Remove the cover from the new BJB and connect both connectors to the new BJB.
7. Install the new BJB into both locking tabs.
8. Attach the battery power cable and tighten the cable nut to 93 in-lb. Tighten the connector bolts to 48 in-lb.
9. Install the battery tray and battery.
