| Re: Code 36 MAF BURNOFF - 89 C4 |
Subject: Re: Code 36 MAF BURNOFF - 89 C4 by Danspeed1 on 2008/5/2 14:46:43 [IMG]http://i142.photobucket.com/albums/r97/BG528/57561871.gif[/IMG] [IMG]http://i142.photobucket.com/albums/r97/BG528/57561872.gif[/IMG] CIRCUIT DESCRIPTION The Mass Air Flow (MAF) sensor measures the amount of air which passes through it. The Electronic Control Module (ECM) uses this information to determine the operating condition of the engine, to control fuel delivery. Due to contaminates in the atmosphere a residue may build up on the MAF sensor sensing wire. To maintain an accurate reading from the sensor, a "burn-off' cycle will occur when the ignition is turned off after the engine had been running a specified amount of time and engine warmed up. The burn-off function is enabled when the ECM grounds circuit 900 which energizes the MAF sensor burn-off relay. With the MAF sensor burn-off relay energized, voltage will be supplied to the MAF sensor terminal "D". Voltage will also be supplied through the normally closed set of contacts in the MAF power relay which will supply 12 volts to terminal "E" of the MAF sensor. TEST DESCRIPTION Numbers below refer to circled numbers on the diagnostic chart. This test will determine if the burn-off function is operative or if the code was set due to an intermittent condition. Check for continuous 12 volts supply to burn-off relay. Grounding circuit 900 should energize the relay and close the contacts. If the test light is dim, check for corroded or fauly connections. If O/K replace relay. With the burn-off relay energized there should be 12 volts supplied to the MAF sensor on terminal "D" & "E" (circuits 993 and 994). DIAGNOSTIC AIDS The Code 36 could have been set due to a poor connection at any of the relays or the MAF sensor. Be sure that these connections and terminals are OK. A faulty MAF sensor should not be considered as the cause if Code 36 is set |
