(dissenting).
I respectfully dissent. The court holds that the district court did not abuse its *544discretion when it denied appellants’ motion to exclude all test results produced by the Intoxilyzer 5000EN because: (1) the government established that the test results are reliable; (2) the district court did not violate appellants’ due process and fair trial rights when it held that appellants could not introduce evidence at trial regarding the alleged source code defects if the Intoxilyzer 5000EN reported a numerical value; and (8) the district court did not abuse its discretion when it held that In-toxilyzer 5000EN results are unreliable if they report a deficient breath sample, unless there is evidence the deficient sample is not the result of a source code error. I dissent from the court’s second and third holdings because there will be cases in which the source code will be probative of whether the Intoxilyzer 5000EN produced an accurate numeric result or accurately reported a deficient sample. Moreover, I have concerns regarding the practical effect of these rulings to the extent they essentially eviscerate the opportunity for an accused to challenge the weight or credibility of Intoxilyzer 5000EN results.
“ ‘Relevant evidence’ means evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” Minn. R. Evid. 401. Generally, “relevant evidence is admissible.” Minn. R. Evid. 402. The court concludes that the district court did not violate appellants’ due process and fair trial rights when it excluded evidence at trial related to alleged problems with the source code because “the source code defects alleged at the evidentiary hearing are not relevant.” Supra at 541. I disagree. It is undisputed that radio frequency from cell phones can affect the Intoxilyzer 5000EN’s results.1 The State’s expert, Dr. Steven Nuspl, testified that cell phone frequencies are not a problem “if one uses a reasonable set of guidelines — like, for example, making sure that cell phones are not in the same room or at least a certain distance away.” The district court concluded, “[f]or there to be any possibility of [radio frequency interference] with 5000EN test results, a cell would have to be remarkably close to the instrument.” Implicitly, then, if proper precautions are not taken, the results will be inaccurate.
I read the court’s opinion as permitting a defendant to mount a pretrial challenge to the procedures the police officer used while administering the test — for example, if the police officer failed to ensure a cell phone was sufficiently far from the testing device.2 In order for the defendant to ascertain whether proper cell phone guidelines were followed, he could presumably cross-examine the police officer who administered the Intoxilyzer 5000EN test. But that cross-examination would be ineffective if the defendant was prohibited from asking questions that relate to the *545reason such precautions are taken. In other words, the cross-examination of the police officer regarding the procedures she followed would not aid the court in determining whether to admit the Intoxilyzer 5000EN results if the defendant cannot ask questions about the reasons for the guidelines.
Second, I disagree with the court’s holding regarding the admissibility of a deficient breath sample. The court frames this as an evidentiary determination governed by Minn. R. Evid. 104(b).3 According to the court, a deficient breath sample is reliable if “there is other evidence or observations that demonstrate the deficient sample was not the result of a source code error.” Supra at 543. This “other evidence or observations” includes “an officer’s observation that the driver did not engage in exorbitantly hard blowing or other conduct that would cause the 240 software to report an adequate breath sample as a deficient sample.” Id. But the court’s holding does not permit a defendant to rebut the officer’s observations with evidence that the source code could have caused the deficient sample. Instead, unless there is a recording of the exchange, a defendant is limited to a credibility contest in which the defendant’s word is the sole evidence available to oppose the police officer’s testimony. See Stephan v. State, 711 P.2d 1156, 1159 n. 6 (Alaska 1985) (cited in State v. Scales, 518 N.W.2d 587, 591 (Minn.1994)) (noting that “it is probably generally valid” that courts are more likely to trust the recollections of police officers than the recollections of criminal defendants). In other words, the State is permitted to introduce evidence to establish that the source code was not at fault based purely on a police officer’s observations, but the defendant is unable to produce evidence to establish that the source code was at fault based on the operation of the source code.
The practical result of the court’s holdings is that defendants will be unable to challenge Intoxilyzer 5000EN results. Despite evidence that the test has a margin of error, that radio frequencies from cell phones can disturb the accuracy of the test, and that the test may erroneously produce a deficient sample,4 a defendant may not raise the source code as a potential cause of an inaccurate or deficient sample. Denying the accused an opportunity to raise source code issues effectively eliminates the accused’s opportunity to challenge the results.
. The source code does not allow a test to be completed if the threshold level of radio frequency interference is detected, but the instrument itself does not confirm whether the radio frequency interference antenna is plugged in.
. Although the court does not directly address this issue, the court of appeals' three-part burden-shifting test takes into account whether a particular operator followed specified procedures. See Noren v. Comm’r of Pub. Safety, 363 N.W.2d 315, 317 (Minn.App.1985) ("The proponent of a chemical test must establish that the test is reliable and ‘that its administration in the particular instance conformed to the procedure necessary to ensure reliability.'" (quoting State v. Dille, 258 N.W.2d 565, 567 (Minn.1977))). If a defendant advances an argument that the administration of the test did not conform “to the procedure necessary to ensure reliability,” it appears such a challenge would occur at the pretrial stage because the argument would be based on a failure to follow procedures, not a source code error.
. "When the relevancy of evidence depends upon the fulfillment of a condition of fact, the court shall admit it upon, or in the court's discretion subject to, the introduction of evidence sufficient to support a finding of the fulfillment of the condition." Minn. R. Evid. 104(b).
. The effect of a deficient sample might be license revocation. Under Minn.Stat. § 169A.52, subd. 3(a) (2010), the commissioner of public safety shall revoke a person’s license if “the peace officer [certifies] that there existed probable cause to believe the person had been driving, operating, or in physical control of a motor vehicle in violation of section 169A.20 (driving while impaired), and that the person refused to submit to a test.” The minimum revocation period "for a person with no qualified impaired driving incidents within the past ten years” is one year. Id., subd. 3(a)(1).