Auto Doctor: Airbag faults often relate to seatbelt issues
Dear Doctor: The "airbag" light on my 2004 Chrysler Sebring convertible comes on and stays on after I start the engine. The default code reader states there is a problem with the passenger seat belt sensor in the buckle. Do you think the reading is accurate and if so, what has to be replaced? What would be a reasonable cost? -- Harvey
Dear Harvey: We see a lot of airbag fault codes due to seat belt buckle issues, and more often corroded wire connections due to moisture connections under the rug as well as insulation on the floor board on various car makes. The first step is to check both Alldata and Identifix for technical bulletins and quick diagnostic and trouble flow charts with connection locations and voltage specs. A qualified technician should be able to figure out the problem. Regarding price, shop around, but plan for one hour or so of labor charges.
Dear Doctor: I have a 2008 Honda Accord with the four-cylinder and get the oil changed every 3,000 miles. The problem I'm seeing is that I'm burning oil very quickly. A few weeks after I get my oil changed I'm already down a quart or two of oil. There are no leaks that I can see. Any idea why I'm burning so much oil, and does this sound normal? -- Chris
Dear Chris: It's no secret that some Honda engines have had oil usage problems due to problem worn valve guides and piston rings. The first step is to make sure there are no oil leaks and that the crankcase ventilation system is working as designed. The next step is to check with the dealer if there are any bulletins or extended warranty programs available. If there are no Honda programs and the crankcase ventilation system is operating as designed, then I would switch to high-mileage oil, staying as close as possible to the recommended viscosity rating.
Dear Doctor: I own a 2002 Chevy Impala V-6. I have a problem with the dome light. When I open the door a second time the light will not come on. When driving and activating the light switch, sometimes it works, other times it won't. Is there something in the door latch? I'm hoping it's not the main light switch. -- Vincent
Dear Vincent: Unlike the old days of just checking power and ground connections, today's vehicles have Body Control Modules that command many features, including the dome light circuit. A technician will connect a professional scan tool to monitor the door entry system. In most newer vehicles, the dome light switch in located on the door latch assembly. In some cases using spray penetrating oil can free up and lubricate the latch mechanism.
Dear Doctor: I have a 2004 Toyota Corolla with 117,000 miles. The alternator/battery light stays on. I took the car into the shop for testing and they said the alternator was fine and working properly, but the original battery was weak and needed to be replaced. Around the same time my daytime running lights stopped working and the automatic on/off of my headlights stopped working. The headlights work correctly in manual mode. Could the two problems be related? -- Mike
Dear Mike: I took a quick look on Identifix web site and found multiple faults with daytime driving light issues. The majority of faults are faulty DRL relays, modules, burned out ground wires and connections behind the instrument cluster. As for the alternator light illuminating, this is not connected to the daytime running light issue. The alternator can charge with the light in the dash illuminating, however it may not charge at full potential.
Dear Doctor: I recently inherited Pop's 1995 Nissan Pathfinder with less than 100,000 miles. It runs fine with the exception of the tachometer. It does whatever it wants to do, sometimes bouncing between 2,000 and 3,500 rpms. Other times it takes 30 minutes to gradually go from 0 rpm to 8,000 rpm. The indicator always goes back to 0 rpm when the engine is shut off. How do I start looking for the problem without destroying an otherwise perfect SUV? -- Don
Dear Don: First, hook a scan tool to the vehicle and see if the tachometer signal is erratic. If the signal to the scan tool is good and the scan tool reads the rpm correctly, then the problem is in the dash cluster. There is a transistor in the coil circuit that can cause erratic primary signals and faulty tachometer rpm signals. This will require a qualified technician.
Junior Damato is an ASE-certified Master Technician. Email questions to firstname.lastname@example.org. Mail questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347