Vehicle Related Conditions

After the battery has been charged or tested and has proven to be a good battery, the cause of the no-start or slow cranking condition must be determined to prevent comebacks. If no obvious cause is evident, the vehicle's electrical system should be diagnosed using the following steps:
1. If the battery passed the load test and the engine still will not turn over or is cranking slowly, the cranking system should be checked.
2. If the cranking system test reveals no abnormal conditions, but excessive cranking is required to start the vehicle, the cause must be diagnosed and corrected to reduce battery demands. Two possible causes for excessively long cranks are the fuel or ignition systems. Refer to Computer and Control Systems. Computers and Control Systems
3. If the battery discharges while the vehicle sits for a few hours or days, the vehicle should be diagnosed for parasitic loads. A simple connection of an ammeter in series with the battery may not find the cause as the condition may not show up when power is restored unless that particular component is repeatedly cycled. Refer to "Parasitic Current Drain". Parasitic Current Drain
4. If a battery becomes discharged and no excessive current drain is found, the operation of the charging system should be checked. Refer to Charging System. Charging System