High-end fixes

Jan. 1, 2020
Every vehicle has quirks about it. Some just have more than others. Check out these stories about higher-end vehicles, a BMW and a Jaguar to be specific, and the lengths these techs went to for a proper, accurate diagnosis.

Every vehicle has quirks about it. Some just have more than others. Check out these stories about higher-end vehicles, a BMW and a Jaguar to be specific, and the lengths these techs went to for a proper, accurate diagnosis.

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09 BMW X5 J2534 Reflashing—Don’t Try This at Home!
By TST Member Adam Varney

A 2009 BMW X5 that was in a minor fender-bender was brought to our shop by the body shop that performed the repair, but needed us to reprogram the car. We’ve performed this procedure on several Beemers, and have a few tips to share with those of you who may be performing a BMW reflash for the first time.

Step 1: For BMW you have to go to BMWTechInfo.com, buy the $30 one-day subscription, and download the reprogramming software on a dedicated computer.

Step 2: Hook everything up including your J-Box (our shop uses a Drew Tech Cardaq, but any approved Passthru device can be used), battery maintainer, and a lap top. 

Step 3: Look out for hazards! The battery should be maintained by a 70A, 14V capable battery maintainer. This is not the same thing as a battery charger! Use of a conventional battery charger can cause problems because of the AC voltage ripple present in the charger. If voltage dips below 13 volts, you’ll see a warning screen telling you to either correct the low voltage condition or end the session. You’ll also want to make sure your cables are all connected well and not located where someone may kick them out by mistake.

Step 4:  Keep yourself busy for five hours. With our J-Box, the process takes about five hours and you need to update all the modules.  It’s a painstaking process of following prompts and commands (such as clicking the OK button, pulling the key out of the ignition, and so on).

You can’t walk away from the vehicle, so find something to busy yourself.

Lost Cylinder Compression from Dripping Injectors
By TST members Kevin Quinlan, Alex Portillo and Craig Truglia

This is the story of a 2000 Jaguar Vanden Plas 4.0 liter that refused to start. The last shop to touch the car fixed the problem by replacing the whole engine. We started from scratch with our diagnosis. Now, any tech knows that there are three ingredients for a properly starting engine: spark, fuel, and an operative engine.

It had fuel and spark, so we next checked the engine’s compression. It was low all the way around at only 30 psi a cylinder when cranking compression should have been closer to 100 to 150 psi. What’s the only thing that can bring compression down equally on cylinders? The timing chain! What do you think?

However, there is one more step to take to insure a proper diagnosis, and that’s to check for applicable Technical Service Bulletins (TSBs). Thanks to a TSB S479, we found out that this Jaguar specific no-start is created by a programming problem.

How so? The old programming left the injectors open too long at engine shut down, causing them to dump too much fuel and effectively washing down all the cylinders.  Over time, this dries up the rings and kills compression. On other vehicles, the same symptom may occur when a customer keeps cranking their engine and stepping down on the pedal until they hydrostatically lock their engine.

The car worked great after an oil change, new spark plugs, a mixture of 10W30 and STP oil treatment squirted in the cylinders to rebuild compression, and a reflash. Keep an eye out for this happening on other cars, as you can never discount the extremely unlikely.  Do simple tests like sniffing the oil on the dipstick, checking the oil level (it may be high), oil color or light the dipstick on fire and see how it burns. This all can indicate gasoline contamination in the oil.

TST Big Event Comes To California
Mark your calendars. On Sept. 29, Technicians Service Training (TST) will be hosting its first West Coast Big Event. This one-day training event will be held at the Ontario Convention Center in Ontario, Calif., from 8 a.m. to 5 p.m.

Registration includes all handout materials, food and refreshments. Scheduled to present are G. “Jerry” Truglia and Dave Hobbs. Truglia’s “P0420s—Keeping the Light Off” covers diagnosing catalytic converter efficiency DTCs the smart way by utilizing a comprehensive diagnostic process that includes looking at fuel trim, oxygen sensors, PCM reflashing, and much more. 

Hobbs’ “Network Diagnostics—CAN Data” covers everything you need to know to diagnose and repair network and communications problems (those pesky U-codes) on domestic and foreign vehicles.  Hobbs covers both pre-CAN and Controller Area (CAN).

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