Motor vehicles equipped with compression ignition (diesel) engines ... Vehicle preconditioning:
1. Vehicles may be tested without preconditioning although for safety reasons checks should be made that the engine is warm and in a satisfactory mechanical condition.
2. Except as specified in subparagraph (d)(5), no vehicle will be failed unless it has been preconditioned according to the following requirements.
3. Engine shall be fully warm, for instance the engine oil temperature measured by a probe in the oil level dipstick tube to be at least 80° C, or normal operating temperature if lower, or the engine block temperature measured by the level of infrared radiation to be at least an equivalent temperature. If, owing to vehicle configuration, this measurement is impractical, the establishment of the engine's normal operating temperature may be made by other means, for example by the operation of the engine cooling fan.
4. Exhaust system shall be purged by at least three free acceleration cycles or by an equivalent method.
