PT Shift "Burp-Free Modification Procedure:For 2001 and 2002 domestic PTs. Does not work on any 2003 PTs. Please read other notes listed to the left. This procedure was created by MX-5 and originally posted at ptdoityourself.net. As well as this mod, MX-5 has provided valuable information to many PT owners through his post on several of the PT Forums, so I would like give him a well deserved "Thanks!" This is a great mod and makes driving your auto trans PT alot more fun! This is a very simple mod. Enjoy! |
MX-5 PT Shift "Burp-Free" Modification Procedure Those of us who have the automatic transmission option are well aware of the slight hesitation felt as the engine accelerates through its sequence of gears. This momentary hesitation is often described as the "shift burp" effect. While reviewing the torque management system in the 2002 service manual one owner (MX-5) has designed a no-cost, easy to apply modification, which will allow you to do away with that momentary "burp" for a quick snappy shift. For a complete description of the procedure go here: http://www.ptdoityourself.net/ptshiftburpguide.html NOTE There has been no testing done on export PT's. Owners are welcome to try it and report their finding. We do not recommend the modification on either the 1.6L gas or 2.2L turbo diesel exports since the PCM wiring is different. This modification does not work on any 2003 model year PT's since there is no wire input or output for the newly designed 2003 PCM. The 2003 PCM seems to have taken over some of the TCM controls. This function is likely an internal pre-programmed one. Early Build Domestic PT's - I was finally able to test the shift mod on an early build PT. These are pre July 24th, 2000 built as 2001 PT's, and easily identified by a cluster of two window switches on the dash, instead of the normal cluster of four switches. The wire will disable the 3-2 passing gear. The low speed 2-1 gear drop still works. Connecting the wire back up will cure the odd shifting. In short, do not cut the wire if the PT has only two window switches on the dash. This change in programming is not covered in the 2001 service manual or it's supplement. It is not necessary to disconnect the battery when cutting the wire, just ensure that the ignition switch is turned off. With this modification you won't experience any fault codes and or a check engine light. The shifts are quick and hard (like they should be). With the snappy shifts, the car will be a little faster. For those with added power, watch for torque-steer to the right. During my nitrous boost, the 1-2 shift will really pull. Hold onto the steering wheel! The TRD Link information is referenced from page 21-189 of the 2002 service manual. Click on each image to enlarge. |
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Locate the Correct Wire The wire, which you need to cut, is yellow with a green stripe. It's just to the inside of the brake master cylinder, at the lower corner of the PCM. This wire bundle has about 30 wires in it. Carefully, open the wire bundle to access the wires. There are 5 yellow wires inside the bundle, but only one yellow wire with a green stripe. (See photo # 1 & 2.) 2 - Yellow/Red Stripe NOTE: Unless you have installed wire loom, as I have, your harness will be black. |
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Strip Back the Harness Covering Carefully strip back the wiring harness covering to expose the wire bundle. |
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Find the Correct Wire Find the Yellow Wire with the Green Strip and pull it away from the bundle. |
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Snip the Wire Carefully snip the yellow wire with the green strip without damaging the surrounding wires. Apply electrical tape to each cut end, then tuck them back inside the wire bundle. NOTE: You may want to attach quick connectors to each end of the cut wire if you anticipate reconnecting the wires at some point in the future. |
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Finishing Up Re-tape the wire bundle to ensure that there is no chance of a short to ground. Replace wire loom, if installed. |
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