12313 - Special Coverage. The chrome layer on the balance chain pins may wear, allowing the chain to stretch. This would cause an engine noise, and if left untreated, could cause the chain to break, leading to engine damage. In addition, the fuel pump plunger shaft seal may wear and allow fuel to leak into the crankcase, setting P0172 DTC, and illuminating the Malfunction Indicator Light. This can cause engine run-on and/or the engine to run rough. If this condition occurs within the stated terms, dealers will replace the engine balance chain and fuel pump.