1. Weak Battery. If your Odyssey’s engine won’t crank or cranks very slowly, then the most likely culprit is a weak or dead 12v battery. Investigating more closely and doing a battery voltage test will clarify whether the starting problem is due to the battery. A test can be done to measure the voltage between the battery poles, check the Auto Stop/Start Issues. Hi Folks, our 2019 Jeep GC's auto stop/start feature has been down for several months now. Finally took it into the dealer yesterday and they first determined that the auxiliary battery was bad and they replaced it but to no avail. This morning they replaced the main battery and called me saying it was fixed. Stop/start technology is more than just a switch wired to the brake pedal and starter – it is a function of the power management system that uses several modules to decide when the engine needs to stop and start. Likewise, diagnostics for stop/start systems are not limited to the starter, battery and alternator. 1. Slow engine crank. The 12 volt battery is a vital component of the starting system in Jeep Grand Cherokee. It powers the starter motor that turns over the engine. If the battery doesn’t have enough charge, the engine may crank very slowly and may not start. Slow crank is usually the first symptom of a dying battery. 1. Weak Battery. If your Compass engine won’t crank or cranks very slowly, then the most likely culprit is weak or dead 12v battery. Investigating more closely and doing a battery voltage test will clarify whether the starting problem is due to the battery. A test can be done to measure the voltage between the battery poles, check the acid For mechanical sympathy, YES. However, manufacturers do report that parts in an auto start-stop vehicle (starter, alternator, battery) are designed to be more durable. For a cleaner environment, NO. If you are regularly stuck in stationary traffic, having the engine turned off has a better effect on the environment. Yep, I tolerate it on my hybrid daily driver because it's just the way it is with hybrids, and unlike the Pentastar, the hybrid's gas engine is actually specifically designed for frequent stop/starts without causing excess wear and tear - also it's less annoying because the electric motor drives the car forward without any delay even before the gas engine has kicked back on, and there's zero Sometimes the engine will start but will idle really badly and may cut out. Cause 2. Bad spark plugs. Worn out or dirty spark plugs are also a common reason why a car cranks but won’t start sometimes. Simply checking if a spark plug is generating a spark is not enough when it comes to modern fuel injected engines. Stop-start certainly entered the public domain fairly poorly; the early systems cut and restarted the engine about as intrusively as a prostate exam. Worse still, with some early efforts they would scare you witless by taking just that millisecond too long to fire back up, just as you were trying to accelerate into a gap in a roundabout. If engine is warm enough the auto start/stop work activate/work either. Your batteries were charged, so that "Check" was passed. Try going out in the morning, drive for about 10 minutes and if temperature is in the 70s or low 80s, it should work. v92p.