Dear Doctor: I have a 2019 Dodge Challenger with the 5.7-liter and eight-speed automatic transmission with under 800 miles. On colder mornings after driving a mile or so, the rpm needle often surges back and forth between 1,200 to 1,500 rpm while cruising at 30 mph in fifth gear and 40 mph in sixth. After a few miles when the engine temperature is up to normal, the needle stops fluctuating. What’s going on? Daniel
Dear Daniel: The vehicle’s computer is in control of the shifting. I suggest you manually shift the car when cold at 30 to 40 mph, and not shift out of fourth gear until the engine is warm or the vehicle speed reaches 50 mph. This will prevent the transmission from hunting up and down. This problem will likely be addressed by Dodge in future computer updates.
Car Battery Questions from our readers to Ask the Auto Doctor:
Dear Doctor: I have a 2012 Honda CR-V and the battery dies, especially in the cold, if I don’t use it for a few days. My local Honda center tested the charging circuit and found no problems, but the battery test fails. Most of the batteries have been replaced under warranty. But Honda can’t seem to give me an answer on what is causing this problem. Any ideas? Bob
Dear Bob: Many Honda vehicles have small 51 series batteries that, in my opinion, are almost too small. We always install a group 24 or 35 battery. If the larger-size battery will not fit, then buy a high cold-cranking-reserve AGM battery. (For proper fit, we disregard the plastic shielding).
Dear Doctor: Our 2005 Mercury Montego with all-wheel drive has only 45,000 miles. There’s a parasitic drain in the system. The battery goes dead when the car is not driven for several days. Two mechanics cannot detect the source of the parasitic drain. Both said my 10-month old battery and charging system checked out great. Is this drain a common issue with the 2005 model-year Mercury and Ford vehicles? George
Dear George: I have seen radio modules, faulty alternators, and even the power door locks cause parasitic draw, as well as most anything that retains system power when the key is off. I suggest you take the car to a qualified shop that employs an ASE-certified technician to examine your vehicle’s circuit. Once the technician locates the circuit with the draw, the next step is to check everything on that circuit to locate the fault.
Dear Doctor: Sometimes my 2013 Dodge Durango doesn’t recognize the key fob. The message center says the key is not recognized, and only after multiple times trying to start the engine does it finally turn over. I have two key fobs and both new batteries where installed by the dealer, who told me a new fob will run around $300. I don’t want to spend money for a new key fob when the problem is in the car itself. This problem is very frustrating. David
Dear David: Sometimes disconnecting the vehicle battery overnight can reset all the modules, similar to rebooting your computer. I would try this first. Other than that, I do think the system will need to be diagnosed with the use of a Dodge-enabled scan tool. The key fob sends a signal the body control module to unlock the push-to-start system.
Dear Doctor: Four days after replacing the battery on my 2015 Honda Accord V-6 with a manual transmission and push-button start, the “starter system” light came on. Prior to that, there was a delay in the engine turning over after the clutch was depressed and the starter button pushed. The first time this happened my dealer cleared the codes, which they acknowledged hadn’t been done when the new battery was installed. The car was OK for two days after the dealer reset, but the same thing happened again. Then the dealer replaced the clutch sensor, which wasn’t working. What’s your opinion on this? Joann
Dear Joann: The battery replacement would not be connected with the push-to-start system. The starter system starts at the switch, then to the clutch pedal safety switch, then to a solenoid, and finally to the (S) terminal on the starter motor. Have a technician connect a test light to the (S) terminal at the starter. Push the start button and depress the clutch, and check to see whether power is at the starter. If there is no power at the starter, then the technician would check power at the clutch safety position sensor.
Dear Doctor: I have a brand-new 2018 Subaru Outback with 5,000 miles. Twice the battery has run down while parked in my garage for two or three weeks. Both times the car was easily started via AAA service. Can I leave a battery charger connected to the Subaru while we are away and the car is not being used for more than two weeks? I wouldn’t want to damage any of the electronics. If so, what kind/type do you recommend? William
Dear William: First, the battery should not go this low in two to three weeks. This indicates the parasitic drain is too much. This car should go back to the dealer for a current draw test. The current draw can be caused by any electric component that retains power with the key off, such as the audio system, power seats and door locks, alarm system, etc. As for the battery charger maintainer, there are multiple brands available at any good auto parts store. Make sure you buy one that has an automatic feature to maintain the battery charge level.
Dear Doctor: My 2008 Cadillac Escalade with 95,000 miles has had all its maintenance and repairs completed by my local dealer. Some time ago the Escalade developed a click sound when turning the key or using the remote start feature, and the engine would not start. Turning the key back to the original starting position and then turning the key again would start the engine. With the remote starter failure, I had to go back to using the standard key. This is now happening more frequently, so the dealer installed a new starter, but the issue has happened twice again since then. Do you have any suggestions? Elaine
Dear Elaine: I would start with a battery load test, followed by checking the battery cable end connections, especially the ground at the engine block and chassis. Actual voltage needs to be checked at the (S) terminal at the starter motor while cranking the engine. In older vehicles, whenever you turned the key to the start position, power went from the ignition switch through either the neutral safety switch or clutch pedal safety switch then to the starter motor. In today’s vehicles, power goes from the ignition switch through the transmission range selector, or clutch safety switch, and then a control module and or the starter relay.
Dear Doctor: I have a 2014 Toyota Highlander with 36,000 miles that I use for local driving. At what point do I replace the battery? Do I wait until I have a problem with it, or should it be replaced at a specific age? Frank
Dear Frank: Batteries should be checked after being in service for two years, and then every year after. I’m seeing battery life three to four years on average, and some batteries do last longer while others die earlier. Today’s vehicles have high-output alternators and engines that start with the turn of the key. In my opinion you should replace the battery now. This will also give the alternator a break to not work so hard.
Junior Damato is an ASE-certified Master Technician.
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