Auto Service World
Feature   August 1, 2003   by CARS Magazine

Davis Instruments CarChip EX

The cure for phantom electrics?


We’ve all encountered the problem. The customer arrives with an intermittent electrical fault that won’t show up no matter how long you troubleshoot. Return the car to the owner, and it reappears. “Phantom” electrical problems aren’t new. But an unusual OBDII data logger called CarChip may be an answer. SSGM tested the Davis Instrument CarChip EX in a 1995 Saturn. The device is a small cartridge that attaches to the under dash data port and rides along for as much as 300 hours of driving. If a DTC is set, the logger “freeze frames” engine parameters at the time the code was set. Information is retrieved by removing the logger and downloading the information into a personal computer using the supplied cables and software. Information can be displayed in either a tabular or graphical form, and the system can reset the vehicle’s MIL lamp.

CarChip allows real-time monitoring of any four out of 23 possible engine parameters, including RPM, throttle position, engine load, coolant temperature, intake manifold pressure, air flow rate, intake air temperature, timing advance, fuel pressure, fuel system status, short- or long-term fuel trim and oxygen sensor output voltage. A technician faced with a MIL but no other symptoms might reset the light, select for the four most probable trouble spots for the given DTC, then turn the customer loose for a few days. When the code recurs, the ability to monitor specific voltage levels should help find intermittents. The unit can be swapped between multiple cars, with each stored independently by the software.

The other interesting feature of the system is its ability to track speed, acceleration and braking. In a sense, it’s a mini “black box” recorder like the airplane versions and in case of an accident, CarChip records the last 20 seconds of driving parameters before the hard braking that precedes the accident. Davis Instruments also suggests that the unit can be used to track your teenager’s driving habits, although that kind of monitoring seems a little like “Big Brother” to this reviewer.

The software is CD-based and is fairly straightforward to use, with an extensive “help” section and sample vehicle readouts to give new users a sense of what to expect. The software is compatible with Windows 95, 98, 2000, XP, ME or NT4.0 and the system requires 5 megabytes of free hard disk space. CarChip works on 1996 and later OBDII vehicles except 2003 CAN protocol models such as the Saab 9-3, Mazda 6, Saturn Ion, and several Ford cars and light trucks.

The system is very easy to install, use and analyze. Gripes? I’d prefer a paper-based user manual (it’s available on the CD in pdf format), and in an ideal world, the ability to monitor more than four parameters could be helpful.

As a whole, CarChip could be a useful new tool to track down frustrating intermittents and at its U.S. MSRP of $US179, it’s not expensive. And when you’re not chasing down stray electrons with it, you can always find out if your daughter is having fun, fun, fun ’till you take her T-Bird away.

Davis Instruments


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