§ 86.1910 How must I prepare and test my in-use engines?

(a) You must limit maintenance to what is in the owners manual for engines with that amount of service and age. For anything we consider an adjustable parameter (see §§ 86.094–21(b)(1)(ii) and 86.094–22(e)), you may adjust that parameter only if it is outside of its adjustable range. You must then set the adjustable parameter to the mid-point of its adjustable range or your recommended setting, unless we approve your request to do otherwise. You must receive permission from us before adjusting anything not considered to be an adjustable parameter. You must keep records of all maintenance and adjustments, as required by § 86.1925. You must send us these records, as described in § 86.1920(b)(3)(x), unless we instruct you not to send them.

(b) You may treat a vehicle with an illuminated MIL or stored trouble code as follows:

(1) If the length of MIL illumination or trouble code storage is consistent with proper maintenance and use, either test the prospective test vehicle as received or repair the vehicle before testing. If you elect to repair the vehicle/engine, but ultimately determine that repairs cannot be completed in a timely manner, you may reject the vehicle from the test program and replace it with another vehicle. If you repair or reject the vehicle, you must describe the MIL or trouble code information in your report under § 86.1920.

(2) If the length of MIL illumination or trouble code storage is inconsistent with proper maintenance and use, either test the prospective test vehicle as received, repair the vehicle before testing, or reject the vehicle from the test program and replace it with another vehicle. If you repair or reject the vehicle, you must describe the MIL or trouble code information in your report under § 86.1920.