PR4 : OBD0? 90-91 USDM Integra LS/GS B18A1

The DA chassis integras received B18A1 1.8L non-vtec motors in 1990 through 1993. The car experienced a switch in engine electronics from 91-92 with the switch from OBD0? to OBD1?. The OBD1 PR4?s are not electrically compatible or at all similar with their OBD0? counterparts.

OBD0? PR4s use a different circuit boards than most other MPFI? OBD0? ECUs of similar vintage, but they are definately based on the same core code. Code from the PM6?, PM7? and other members of the family will generally run, but many secondary/peripheral engine functions will not work properly.

Additionally, there were at least 2 different 90-91 PR4 hardware platforms. The key difference is the presence or absence of an internal PA sensor. ROMs marked "33" or "54" usually come in ECUs without an external PA sensor, while ROMs marked "92" usually come in ECUs with an internal PA sensor. Code 13 that will not go away are generally caused by the wrong code base being used.

• obd0_pr4-r33.bin: PR4 without internal PA, EPROM #33
• obd0_pr4-54.bin: PR4 without internal PA ROM #54
• obd0_pr4-92.bin: OBD0 PR4 with internal PA, ROM #92

Attachment:	Modify:	Size:	Date:	Who:	Comment:
PR4_A02_top.jpg	mod	172132	18 Dec 2003 - 21:55	The Admin	TJ's scan of top of manual PR4-A02 w/o PA sensor
PR4top.jpg	mod	469558	18 Dec 2003 - 21:52	The Admin	Scan of top of manual PR4-A10 with PA sensor
PR4closeTJ.jpg	mod	83456	18 Dec 2003 - 21:56	The Admin	TJ's closeup of 6260/MCU - very different from PM6
PR4back.jpg	mod	554568	18 Dec 2003 - 21:52	The Admin	Scan of bottom of manual PR4-A10 with PA sensor
PR4_A01_top.jpg	mod	601036	18 Dec 2003 - 21:53	The Admin	Scan of top of manual PR4-A01 without PA sensor