A The Alldata automotive database pulled up bulletin 18-003-05, dated January 2005, that addresses the fluctuation of interior lights and headlights upon a cold start. The bulletin calls for selectively erasing and reprogramming the powertrain control module (PCM) with Chrysler's StarScan scan tool. If the vehicle is still under warranty, this would be covered. Labor time is less than one hour.
Q I have a 2001 Suburban with 76,000 miles on it with the Autoride feature. At 75,000 miles the "Service Ride Control" light came on. It was intermittent at first but now comes on when I back out of the garage or shift into drive. The vehicle sits level, and the ride seems as good as ever. The dealer says it could be a loose wire, a shock absorber or sensor, the computer controller, etc. All of which would be expensive. Is there any inexpensive way to troubleshoot the problem? Will any harm come from driving the vehicle as is?
A As with most electronically controlled systems on modern motor vehicles, they have built-in self-diagnostic capabilities. Thus, use a scan tool to look for diagnostic fault codes involving the electronic ride control system. If code C0580 is present, service bulletin 03-03-11-001, dated July 2003, identifies the possibility of a lack of clearance between the right front shock absorber solenoid connector and the A/C evaporator hose creating a poor electrical connection, which is a fairly simple fix. Although it's unlikely you'll cause any damage by driving the vehicle as is, I'd suggest at least troubleshooting the problem to see if it's an inexpensive repair.
Q I bought a used 2005 Buick LaCrosse with the 3.8-liter V6 engine and 61,900 miles in immaculate condition. I change the oil at 3,000-mile intervals, but I notice 1- to 1 1/2-quart usage between changes. Recently the "Check Engine" light came on and the dipstick showed almost no oil. The Buick does not smoke or show leaks, and it runs just fine. Before I go to the dealer, could you check your database for reasons for this condition?
A GM says that oil consumption of one quart or less per 2,000 miles is within normal specs. Higher oil consumption can have several causes, including engine wear and tear, high engine oil operating temperatures, clogged PCV system, oil dilution and heavy engine loads from towing. GM service bulletin 05-06-01-035A, dated December 2008, describes excess oil consumption on some 3800 Series II/III V6 engines potentially caused by exhaust valve seals slipping out of position and no longer sealing oil from being drawn past the valve guide.
Q My daughter in-law has a 2005 Chevy Suburban with 60,000 miles. When she puts it in gear and accelerates, the engine revs, but the car will go only 5 miles per hour. If she backs off the throttle and accelerates again, the car acts normally. This problem is intermittent. Any ideas?
A My first suspicion is a problem with the transmission's valve body. Debris in the pressure control solenoid screen could limit hydraulic pressure initially, causing the slippage she's experiencing when she first hits the throttle. Similarly, a binding or sticking valve in the valve body could cause the same thing.
A scan tool might identify a transmission fault code pinpointing the problem, but try a half-can of SeaFoam Trans-Tune added to the transmission fluid for several weeks, then consider a complete transmission flush/filter/refill.
Most important, she should immediately lift out of the throttle when the transmission begins slipping. This slippage can cause serious transmission damage quickly. Don't ignore this.