Underhood - Service Repair

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Taking care of today's vehicles

One little oversight can result in big — and costly — mistakes.
Thursday, June 26, 2014 - 07:00
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In addition to having to adjust your oil change habits of yesterday to keep up with the technology of today, other areas we once considered “routine” have changed. Not all are new, but many of these are still giving technicians fits from lack of information and training. One example is Tire Pressure Monitoring System (TPMS) reset. It’s something we all need to deal with, even if we are just rotating tires. Some TPMS systems are very simple, while other vehicles need a special tool to reset the system or program new locations into the Electronic Control Unit (ECU) in charge. Another “routine” service area that isn’t so routine anymore is brake service. With more electronic braking systems coming into play, and electronically-actuated parking brakes installed, beginning a routine reline could end up costing you a lot more than a set of brake pads to fix.

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Why Perform Maintenance Work?
It’s time to move on to problem vehicles that came in with issues that could have been avoided if the proper maintenance was performed. Our first vehicle is a 2002 Saturn SC1 1.9L that came in with a P0341 (Figure 2) cam sensor Diagnostic Trouble Code (DTC). This DTC can be confusing for the tech who is not familiar with this vehicle. The 1.9L engine does not have a cam sensor, but rather uses the Electronic Ignition (EI) that has capacitive pickup plates located under the 1/4 coil pack that determines the polarity sequence for a cam input.

The cause for this problem was a neglect of maintenance on this vehicle that had not seen routine service in a few years or more. How is that related? Worn spark plugs lead to wider plug gaps. This, in turn, leads to a higher energy demand in order to fire. And while coils are more than capable of meeting the demand, they are not designed to do it all the time. They overheat and the secondary insulation breaks down, leading to a shorted coil. This fix for this vehicle was new spark plugs, wires and the No. 1-4 cylinder ignition coil.

Our next story is about a 2008 MB GL450 4.6L with air suspension that came in with a message “AirMatic Service Required” after the vehicle was serviced at another shop. The owner of this Benz went for the cheapest oil change he could find which wound up costing him more in the long run. This wasn’t exactly caused by lack of maintenance as it was by lack of knowledge and training. The problem occurs if the vehicle is lifted without first turning off the air suspension system. Any trigger, like a door opening, could activate the system with no load on the suspension. The air suspension spring can be damaged or moved off its seat. Ford products with air suspension systems had a switch in the trunk (or at the passenger’s side lower trim panel) to turn off the air suspension, but the Benz has to be turned off via a scan tool or may be turned off on some models by the control module automatically. Make sure before you lift up a vehicle, you check if it has air suspension and know how to turn it off and don’t forget to turn it back on when you let the vehicle down.

How about a 2004 Ford F150 XLT 4.6L with 186,000 that has not seen ignition maintenance in over 90,000 miles? Well you probably know where I am going with this one if you have had the joy of removing the spark plugs (Figure 4) on this engine. Because the plugs have a tendency of breaking there are a couple of things that you can do before removing them. The following are a few things that you can try before removing the plugs. First, warm up the engine; second, perform a fuel system cleaning/decarbonize before remove the plugs; and third, pray and make sure you have the special tool (Figure 5) that removes the broken plug along with an air vacuum to suck up any small debris that may have been left behind.  

Or a 2002 Cadillac Escalade 6.0L with 80,000 on the odometer with a brake problem that could have been avoid in two ways. The first way she could have avoided a costly repair was when she first heard the noise (Figures 6 and 7). She should have brought the vehicle right in rather than continue to drive. You’ve never had a customer like this one, have you? As you can see, she drove the vehicle until the caliper blew out. The other way she could have saved a boatload of cash was to have had the service done when the shop first recommended the brake work.

FIGURES 5-7

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