Article: "Wet or frozen AMC access considerations," Haight, S.

2010 Vol. 5 Iss.1

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ollision C The International Compendium for Crash Research

Volume 5 Issue 1

Collision: The International Compendium for Crash Research

Spring 2010

Common Post-impact Speed Analysis Effect of Directional Tires on Wet Traction

CDR Technology An Abbreviated History

WET or FROZEN

ACM Access Considerations

Volume 5, Issue 1 - Spring 2010

Rollover Crash Reconstruction A Variable Deceleration Rate Approach

Insurance Applications

For CDR Legal Considerations

If you found this article useful, look into a subscription to Collision Magazine at www.CollisionMagazine.com

Find out more about the next EDR User’s Summit at EDRSummit.com

Contents

SPRING 2010

of interest 10 8 12

Calendar of Events My Turn at the Wheel "Gear-Up!"

16

Effect Of Directional Tires On Wet Traction

features

- H. J. Herzlich, Robert Swint, Edward Ritsch and B. Unser

28

wet or frozen acm access considerations - Sean Haight

36

28

Insurance Applications for Crash Data Retrieval, Legal Considerations - Michael Merolli, David Brink, Patrick Conran, and Jasmine Garcia-Vieux

44

CDR Evidence Suppressed by Oklahoma Court

50

- George Hall

50

An Abbreviated History Of CDR Technology - Rusty Haight

74

A Variable Deceleration Rate Approach to Rollover Crash Reconstruction

74

- Nathan Rose

84

Retrieving and Interpreting Data from Ford Powertrain Control Modules using the Bosch Crash Data Retrieval Tool

96

- Bruce McNally

96

Common Post Impact Speed Analysis - Greg Russell

104 EDR Module Types and Collision Data Available in CDR Supported Vehicles - Chuck Veppert and David Little www.collisionpublishing.com

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wet or frozen acm access considerations Sean Haight Collision Safety Institute

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I

ntroduction Evaluating Airbag Control Module survivability has been a topic of relatively limited research and testing although there have been several narrowly focused projects addressing durability and survivability as seen later in this narrative. Since every type of environmental scenario simply cannot be tested, research must be focused and ongoing. This report discusses the survivability of multiple Airbag Control Modules in situations where they are powered up while in different forms/states of liquids.

"Group: Obviously the preferred method is to conduct the download with the ACM still in the vehicle.

However, what call do you make when the ACM is obviously wet? Do you refrain from putting any power to the unit, remove and dry it, and then do a bench download (in this case talking about a GM SDM). (Video tape the removal, ect.) Or do you take a chance that you might fry it, put power to it while still in the vehicle, and then remove only if unsuccessful?"

The Bosch preferred Crash Data Retrieval Certification Course material, which follows the CDR software Help file’s best practice recommendation, indicates that the first, best method for any routine CDR imaging is to connect through the Diagnostic Link Connector or DLC. This method utilizes the internal wiring and communication in the vehicle and provides a quick and easy method to retrieving crash data. However, the question remains: what are the consequences of such an attempt to imagine if the module is obviously wet, having been previously soaked, submerged, or frozen in a liquid?

Some have suggested that attempting with a DLC connection could destroy the electronic components inside of the module and potentially render the data useless.

This scenario was discussed on the Yahoo! CDR User’s Group in this post and the ensuing thread:

This forum post suggests a possible flaw in routine operation. One might consider what would happen to a mobile phone under the same environmental conditions.

Imagine yourself accidently falling into a pool or pond with your phone still in your pocket. In most cases, these type of mistakes ruin your favorite personal electronics and they are often un-repairable. When electronics are placed in non-distilled water, for example, the ionic elements in the water will short out the connections on the printed circuit boards. This will cause damage to the internal components of the device. How does this analogy compare to the Airbag Control Module?

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P

rior Research Previously published research on this subject, as it relates to fluids, can be found in the article "EDR Durability and 49CFR63 Survivability Requirements" by Wade Bartlett.

This research was published in Collision Magazine, Volume 2, Issue 1. Bartlett performed several submersion tests including salt and fresh water. In addition, tests were performed on modules in frozen conditions. It was concluded that "EDRs (sic) will [not] have any difficulty in meeting the survivability requirements newly outlined in 49CFR563." In the Federal Regulation 49CFR563.10, we find the minimum survivability requirements for vehicles, however it does not describe scenarios involving water (whether liquid or solid). Bartlett also concluded that “EDRs (sic) have commonly been seen to survive crashes much more severe in nature than anything specified in the FMVSS regulations, including fires, physical damage, and submersion.” While this research answered some of the questions involving Airbag Control Modules, it still left uncertainty regarding powering up these modules in a submerged or frozen state. Bartlett’s research addressed a module that had been wet and was, when the attempt to image data was made, had been dried. The underlying separate question addressed here was: “if the module is still wet (or frozen) when there’s an attempt to image would something related to the module being wet effect the data?”

T

est Procedure To further explore the ramifications of powering up an ACM while in a liquid, a series of tests were conducted with a group of airbag control modules (ACMs). The “Scientific Method” suggests that each experimental procedure be based on the principles of gathering observable, empirical, and measurable evidence and information. In addition, before the test is performed a hypothesis must be made to project expected or anticipated results. One possible outcome from submerging an ACM in a liquid like water would be that there is no communication with the module or, in other words, the Bosch hardware/software simply could not recover the information stored in the module. Another possible outcome is that the data was recoverable even while the module is submerged or frozen. Since the Bosch CDR software protocol includes multiple (3) passes or checks of the incoming data, it is also possible that one of the outcomes would result in a match error. This would mean that the data was collected for one pass but it failed for another. One other potential outcome is that that the data stored inside of the module, or the module itself, could be erased or destroyed entirely (“fried”).

Five Airbag Control Modules were selected as the test specimens.

Four of them were Delphi SDM-RSDD modules from General Motors vehicles. These modules were selected because they are the least watertight of the modules available and are easiest to open and expose the internal electronics directly to a fluid. Four of the same modules were selected to have a larger sample of the same modules under different scenarios. A fifth module, a Takata RCM from a Ford Crown Victoria was also used to give some module variety to the experiment (that module was opened to similarly expose the internal electronic components). The modules were labeled 1 through 5 (see figure 1).

Prior to any survivability test, every module was downloaded to provide a baseline data file. None of the modules had previously been exposed to fluids as they would be in this test series. All of the modules were downloaded for baseline data without any connection issues. Table 1 shows the event names that existed before any fluid based tests were performed. After successful baseline downloads of all 5 modules, they were put to the test in various liquid related scenarios.

Module 1

Deployment

Module 2

Deployment

Module 3

Deployment

Module 4

Deployment

Module 5

Deployment

Non-Deployment (only stores one event)

Table 1: Summary of events stored in each test module prior to experiment.

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est 1 The first experimental scenario examined how an ACM would download in a solid, frozen state. To set this up, the metal cover of module number 1 was removed and the module was placed in a container with household, unfiltered tap water. It was then placed in a freezer for more than 24 hours (see figures 2 and 3). Special consideration was given to the placement of the module in the water before freezing such that the water level of the container submerged the entire module up to the main pin connections (see figure 4).

Figure 1: Test modules 1-5

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Non-Deployment

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Figure 2: Placing Module 1 in a container to be frozen Figure 3: Frozen Airbag Control Module The frozen module, or “SDMcicle,” was removed from its container as a block of ice and immediately connected to the Bosch CDR interface using the appropriate direct-to-module cable. The VIN for that module was entered into the CDR software and the download process was initiated. While completely frozen, the module was successfully downloaded without any errors. In addition, the CDR software reported that both the Deployment and Non-Deployment data were unchanged from the baseline download.

Figure 4: Close-up of pin connections on Module 1

After just minutes of sitting at room temperature, the ice had started to melt back into its liquid form. Once the ice had melted to the point where there was standing ice but the module was still wet, a downloaded was again attempted. This time; however, the CDR software was not able to connect to the module. The error dialog box read: "Collect data failed! No Communications with module. Please check DLC cable or cable to module" (see figure 5). The module was disconnected and the remaining ice was removed. The module was then placed outdoors in the sun for about 30 minutes. After the visible residual water had evaporated from the components, the module was connected back to the CDR interface and computer. After www.collisionpublishing.com

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that drying was complete, the module was successfully downloaded.

The CDR software reported that both the Deployment and Non-Deployment data were un-changed from the baseline download.

T

est 2 The second test was designed to simulate liquid submersion after the download has stared. Module number 2 was connected to the Bosch CDR interface by the direct-to-module cable and placed on a table (see figure 6). The VIN number for the module was entered in the software and the download was initiated.

After the first pass was complete, and the second pass had just started, the module was carefully placed into a bowl of generic tap water (see figure 7) making sure the direct-to-module cable remained in place.

The rest of the download process was concluded with the module still in the water bowl.

The CDR software did not successfully image the module and the following error was reported: "Collect data FAILED! Software ID: 0073. Read one: Passed. Read two: Passed. Read three: Passed. Match: FAILED. Check power to interface and the communication cables.

Turn ignition off for five seconds, then turn ignition on and try again.

Make sure vehicle ignition switch is on and engine not running.

Check vehicle battery voltage. Possible incorrect system selected." (see figure 8).

Figure 5: Collect Data error message

Like module 1, this module was then placed in direct sunlight for about 30 minutes. In addition, a can of compressed air was used to remove any remaining water droplets. The module was again connected to the CDR interface and computer. After this drying process, another download was attempted and ran to completion with the CDR software reporting that the Deployment data was un-changed from the baseline download.

Test 3 The third test was designed to simulate an Airbag Control Module that is in still, fresh water; completely submerged. Module number 3 was placed in the same bowl of fresh water as test number 2. It was connected to the CDR interface module and computer (see figure 9). Like the previous tests, the CDR software was started and began downloading the data from the module. The CDR software was not able to connect to the module. The error message read: "Collect data FAILED! No Communications with module. Please check DLC cable or cable to module" (see figure 5).

Figure 6: Direct-to-module cable connection

The module was dried using the previously described combination of the exposure to the sun and air can drying techniques. After the remaining water was removed, the module was downloaded without any errors and the two events that were previously observed in that module had not been changed from the baseline download.

Figure 7: Module 2 placed in a container with tap water.

T

est 4 In addition to fresh water, an ACM was also placed in salt water. For this experiment, a sample of sea water from San Diego bay was collected and placed in a similar bowl. The salt water was captured near the end of the bay nearest the ocean where chemical and metal residuals would be minimal. There were the typical biological particulates observed the salt water such as bits of kelp and silt (and one live ghost shrimp). Module number 3 was connected to the CDR interface module and then placed into the bowl of salt water (see figure 10). After the module settled in the water, it was downloaded using the same procedure as observed in the previous tests.

Like test number 3, the CDR software could not make a connection with the module and it provided the error: "Collect data FAILED! No Communications with module. Please check DLC cable or cable to module" (see figure 5).

The module was then dried as was done in the previous tests. After the remaining water was removed, the module was downloaded without any errors and the two events that were stored had not been changed from the baseline download.

Figure 8: Match error message 32 Collision

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Figure 9: Connection method while the module was submerged

T

est 5 Considering that these modules are installed in vehicles, that may contain several types of automotive fluids and hazardous materials, one test was attempted with a “typical” vehicle fluid. Test number 5 was designed to simulate a severe crash were fluids from the engine compartment may have leaked into the passenger compartment and flooded the Airbag Control Module. For this experiment, engine coolant was used as the test liquid based on the idea that it would be most readily available in quantity in a car after a crash.

Module number 4 was connected to the CDR interface and the computer, placed in the coolant, and download attempted (see fig-

ure 11). The CDR software could not collect the data from the module and provided the same error message as tests 3 and 4 (see figure 5). The module was taken out of the coolant and rinsed in tap water. It was dried and downloaded again with no errors. Like the previous tests, the collected data was identical to the baseline download.

T

est 6 The last test was a interesting hypothetical scenario. It was designed to simulate the driver with the over-super-sized ultra-44 ounce cup of cola getting in a collision coming from the local convenience store. To create this scenario, a 2 liter bottle of generic cola was poured into the same bowl as the previ-

Figure 10: ACM submerged in salt water (left) Figure 11: ACM submerged in engine coolant (right)

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ous tests (see figure 12). Cola was selected has having a reputation of being highly corrosive. This was another reason for this particular test. Module number 5 was connected using the appropriate direct-to-module cable and a download was attempted.

This test provided the most visually interesting results of the entire experiment. Once the power was connected to the CDR interface module, the cola started to fizz and bubble aggressively (see figure 13). This reaction occurred very rapidly after the power was connected. Similar to the previous submersion tests, the ACM was not successfully downloaded and the connection error previously returned was observed. The module was taken out of the cola and rinsed in regular tap water. It was dried and downloaded again with no errors. Like all the previous tests, the collected data was identical to the baseline download.

A

nalysis Test 1 indicates that completely frozen water encasing a module does not have an effect the data collection process, nor does it damage the module in any way. This is most likely due to the fact that completely frozen ice is not a conductor. This means that ice does not allow the electrons to flow across it like metal or other minerals would. Once the ice starts to melt however, the electrons move freely through the non-distilled water left behind. Like tests 3, 4, 5, and 6, the conductive liquids that the modules were placed in cause shorts in the connections of the different internal components. This short caused communication problems and the CDR system was not able to retrieve the data from the module memory.

More importantly, none of the modules tested in these liquids were permanently damaged. After they were dried, the short circuit conditions were removed, and the module worked perfectly. None of them were "fried" from the electrical currents applied while wet and none of the data was lost. In addition, exposure to corrosive liquids like salt water and cola caused no short term damage on ACMs while they are powered up. Lastly, hazardous materials like engine coolant also have no short term effect on an ACM when it is being imaged.

Figure 12: Placing Module 5 in a container filled with cola

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onclusions The purpose of this experiment was to provide a reasonable set of data and a baseline protocol for downloading an Airbag Control Module while it is obviously submerged or may have been submerged in liquid or frozen. Based on these results, attempting to download a seemingly submerged or frozen module through the Diagnostic Link Connector is still the first, best method for collecting crash data and even if the module has been wet, the most likely result will be a communications failure not a loss or “corruption” of the stored data. While this experiment was conducted on a small sample of modules in a small sample of liquids and there are many different variations of ACM types and many different types/solutions of liquids which may reach a module in a vehicle after a crash, the selection here seems to be demonstrably representative of the potential for the module-fluid exposure combination likely to be encountered in the field.

Figure 13: Result of powering-up a Airbag Control Module in cola 34 Collision

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