Auto Service Professional

JUN 2018

Magazine for the auto service professional

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J u n e 2 018 A SP 53 USA MANUFACTURER OF INNOVATIVE TOOLS & EQUIPMENT 845-679-4500 24-Hour Repair/Replace Warranty • © 2018 Innovative Products of America ® Incorporated. All rights reserved. #9038A #8016 Relay Bypass Switch Kit with Amp Loop Fuse Saver ® Master Kit • Run automotive, 12V DC motors with the push of a switch • Simplifies fuel injection testing • Use in conjunction with clamp-on Amp Probes and Lab Scopes • Provides a level of versatility in electronics testing (5-30 amps) never before available • Allows a technician to move around a vehicle shake testing wires while looking for the short Includes: 5 Color-Coded, Resetting Breaker Handles (5-30 Amps), BuzzAlert™ Audible, Short-Circuit Alert Module and 6 Custom Fuse-Type Adapters Allows Circuit Bypass and Current Testing for 12V DC Relays Chase Down Short Circuits Without Blowing Fuses MAD E IN U S A M A D E I N U S A O F G L O B A L COMPONENTS (Amp Probe Not Included) codes and provide system data that will aid in diagnosing the fault. A good volt ohm meter and a couple of other inexpensive and easily obtained parts will also help in many output is- sue diagnostics. e SRS control module is constantly moni- toring all of its circuits and components for the proper operation, resistance and shorts to power or ground to ensure that the equipment will function as designed when needed. Because most SRS airbag inflator circuits are typically two-wire circuits, resistance is- sues are common. A resistance that is too high or too low will set codes. It's important to re- member that a seat belt pretensioner also fea- tures a small explosive charge monitored and controlled by a two-wire circuit. e normal resistance across these inflator circuits is about 1 to 3 ohms and this data is usually displayed in the SRS data using a scan tool. Some newer Mazda models have a wider range of 0.8 - 9.85Ω. Diagnosing these circuits and resistance codes following the factory di- agnostics usually requires specific SRS load tools to substitute the removed inflator/deploy- ment circuits. But the same testing can be achieved with a scan tool, up-to-date service information and a few 1/4 watt 1, 2, and 3Ω resistors. A 3Ω resistor will work just fine on the new Mazda, too. e following common issues can all be di- agnosed without any special equipment by just using a 2 or 3Ω test resistor in the component connector of concern. is test resistor will verify the integrity of the wiring and module operation. Aer you have gained access to the component connector that has the resistance issue and have confirmed that corrosion or a loose connection isn't the issue, you can sub- stitute the test resistor of the appropriate resis- tance into the circuit to simulate the inflator. en clear the code and see if the code returns. If the code doesn't return, the issue is likely in the inflator. If it does return the issue is in the wiring or module and more testing is going to be required. 2005-2009 Ford Escapes will set a code B2292 high resistance in the passenger side Circle 118 on Reader Service Card

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