Some 2007-08 TL, 2007-12 MDX and 2010-12 ZDX models may produce a squeak from the accessory drive belt when the engine is started cold and allowed to idle.
A likely cause for the noise is the rubber formulation of the belt, and in some cases, misalignment between the a/c compressor and belt pulleys. The correct fix depends on the year, model and VIN of the vehicle you're working on.
On 2007-08 TL models, 2007-10 MDX models, 2010 ZDX models and 2011 MDX models built from VIN 2HNYD2 BH500001 through 2HNYD2 BH512245 and 2011 ZDX models built from VIN 2HNYB2 BH500001 through 2HNYB2 BH500146, replace the drive belt with an improved design, part #38920-RCA-A01, along with upgraded A/C compressor mounting bolts, part #90023-R70-A00.
On 2011 MDX models built from VIN 2HNYD2 BH512246, 2011 ZDX models built from VIN 2HNYB2 BH500147 and all 2012 MDX and ZDX models, replace the drive belt alone.