94 hatch throwing a code
28-May-2004, 08:42 PM
#1
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Location: Southern California
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94 hatch throwing a code
ok here it is.... my buddies 94 hatch was throwing an 02 sensor code so he replaced it.... when he disconnected the battery for 15 minutes to reset the ECU, the code is still getting thrown..... we even took out the fuse in the fuse box to reset the ECU and it is still doing it.
anyone have any ideas? the sooner we can fix his car the better, hopefully by monday
-JASON
anyone have any ideas? the sooner we can fix his car the better, hopefully by monday
-JASON
31-May-2004, 08:59 AM
#4
Jason, the O2 sensor code is never thown when the O2 is at fault. Sounds wierd, but the ECU has no idea if the O2 is working or not, that's why in OBD2 they have 2 O2s, so they can verify each other plus they can verify the catalytic converter. In OBD1, the O2 has no checkpoint. It's only thrown when the engine is running rich, which can be 100 different problems. Like a missfire due to bad ignition, or misfueling due to a bad MAP sensor or a bad engine coolant temp sensor. It's time for a tune-up, air filter change, oil change... the works!! Then, test each and every sensor right at the ECU plug. Read every value and compare it to the book. Whatever gives a false reading, replace it.
02-Jun-2004, 06:06 AM
#6
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Location: Southern California
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hey bruno, could a vaccuum leak be at fault? or would that throw a different CEL code? cuz he thinks he also has a vaccuum leak cuz it idles rough...
thanx for the help, that will stop him from buying another o2 sensor.... he almost did but i said wait and ill ask here first to see what was wrong, and you came through....
thanx for the help, that will stop him from buying another o2 sensor.... he almost did but i said wait and ill ask here first to see what was wrong, and you came through....
02-Jun-2004, 08:43 AM
#7
it can be a vacuum leak too. cars that old, it's hard to say. you have to start with the basics... get a vacuum gauge and pull a vacuum line - read what kinda vacuum it's getting. You often do NOT get a code for a vacuum leak if it's small enough. Hondas are very finicky with vacuum leaks cuz we use a MAP sensor, not MAF. What kinda mileage is the car getting?
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