Jeep Cherokee Won’t Start But Has Power, Causes #5: Defective Spark Plug. Let’s say your Jeep Cherokee won’t start if the battery, starter, gas tank, and fuel pump aren’t in good condition. In that case, you need to check the spark plugs. You may locate the spark plug wires by opening your Jeep’s hood. 5 days ago · 144 K - 156 K. $ 1606. $ 647. Repair Costs. Scheduled Maintenance Costs. Calculations based on 12,000 miles driven per year. This is an estimate of what you might expect to pay for routine hb2xhSp.