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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 PR4s 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.

%META:FILEATTACHMENT{name="PR4top.jpg" attr="" comment="Scan of top of manual PR4-A10 with PA sensor" date="1071784332" path="C:\Temp\wiktemp\PR4top.jpg" size="469558" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4back.jpg" attr="" comment="Scan of bottom of manual PR4-A10 with PA sensor" date="1071784358" path="C:\Temp\wiktemp\PR4back.jpg" size="554568" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4_A01_top.jpg" attr="" comment="Scan of top of manual PR4-A01 without PA sensor" date="1071784429" path="C:\Temp\wiktemp\PR4_A01_top.jpg" size="601036" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4_A02_top.jpg" attr="" comment="TJ's scan of top of manual PR4-A02 w/o PA sensor" date="1071784503" path="C:\Temp\wiktemp\PR4_A02_top.jpg" size="172132" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4closeTJ.jpg" attr="" comment="TJ's closeup of 6260/MCU - very different from PM6" date="1071784577" path="C:\Temp\wiktemp\PR4closeTJ.jpg" size="83456" user="TheAdmin" version="1.1"}%

The PR4 came in two variants - the OBD0 PR4 and the OBD1 PR4.

%META:TOPICINFO{author="TheAdmin" date="1071784800" format="1.0" version="1.1"}% %META:TOPICPARENT{name="ConsolidatedEcuList"}% 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 PR4s 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.

%META:FILEATTACHMENT{name="PR4top.jpg" attr="" comment="Scan of top of manual PR4-A10 with PA sensor" date="1071784332" path="C:\Temp\wiktemp\PR4top.jpg" size="469558" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4back.jpg" attr="" comment="Scan of bottom of manual PR4-A10 with PA sensor" date="1071784358" path="C:\Temp\wiktemp\PR4back.jpg" size="554568" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4_A01_top.jpg" attr="" comment="Scan of top of manual PR4-A01 without PA sensor" date="1071784429" path="C:\Temp\wiktemp\PR4_A01_top.jpg" size="601036" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4_A02_top.jpg" attr="" comment="TJ's scan of top of manual PR4-A02 w/o PA sensor" date="1071784503" path="C:\Temp\wiktemp\PR4_A02_top.jpg" size="172132" user="TheAdmin" version="1.1"}% %META:FILEATTACHMENT{name="PR4closeTJ.jpg" attr="" comment="TJ's closeup of 6260/MCU - very different from PM6" date="1071784577" path="C:\Temp\wiktemp\PR4closeTJ.jpg" size="83456" user="TheAdmin" version="1.1"}%