Resetting the PCM
Resetting the PCM Will disconnecting the battery for about 30 minutes reset the PCM? I disconnected my battery from the positive terminal for about 40 minutes and my PCM did not reset. I judge this by looking at my trip odometer and radio. Why would the PCM not reset after doing this? My dad says theres probably a back up battey or something, which I don't believe.
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
Don't know about the radio and trip odo after battery disconnection, don't think the PCM cares about them. Try it this way:
Turn key on, don't start car
Pull PCM BATT and PCM IGN fuses in engine compartment
Wait 5-10 min
Turn ignition off
Replace fuses
Resets the readiness tests too and idle will be grumpy until it relearns.
Turn key on, don't start car
Pull PCM BATT and PCM IGN fuses in engine compartment
Wait 5-10 min
Turn ignition off
Replace fuses
Resets the readiness tests too and idle will be grumpy until it relearns.
LS1Tech Sponsor
Joined: Dec 2005
Posts: 2,932
Likes: 12
From: CT
also, after you disconnect the cable, step on the brake pedal a few times and turn on your headlights... this will drain any residual power left in the system...
trip odometer's don't reset, and it depends on the radio... for mine, my saved stations didn't get cleared out, but the clock did get reset, as well as my compass...
also on my car, when power is lost via pulling fuses or the battery cable, the keys get LOCKED into the ignition.. I wouldn't do it with the keys in the car...
trip odometer's don't reset, and it depends on the radio... for mine, my saved stations didn't get cleared out, but the clock did get reset, as well as my compass...
also on my car, when power is lost via pulling fuses or the battery cable, the keys get LOCKED into the ignition.. I wouldn't do it with the keys in the car...
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
Don't know about the radio and trip odo after battery disconnection, don't think the PCM cares about them. Try it this way:
Turn key on, don't start car
Pull PCM BATT and PCM IGN fuses in engine compartment
Wait 5-10 min
Turn ignition off
Replace fuses
Resets the readiness tests too and idle will be grumpy until it relearns.
Turn key on, don't start car
Pull PCM BATT and PCM IGN fuses in engine compartment
Wait 5-10 min
Turn ignition off
Replace fuses
Resets the readiness tests too and idle will be grumpy until it relearns.
Also you said you only disconnected the positive? General rule always disconnect the negative side of the battery first. disconnecting the positive and leaving the ground still attached is not a good idea.. if you touch the positive side of the battery to anything with the ground still connected the potential is there to get a shock or fry electrical systems.
+1 thats the way to reset the pcm in an F-body. The PCM doesn't control the radio or the trip so reseting the PCM will do nothing to those.
Also you said you only disconnected the positive? General rule always disconnect the negative side of the battery first. disconnecting the positive and leaving the ground still attached is not a good idea.. if you touch the positive side of the battery to anything with the ground still connected the potential is there to get a shock or fry electrical systems.
Also you said you only disconnected the positive? General rule always disconnect the negative side of the battery first. disconnecting the positive and leaving the ground still attached is not a good idea.. if you touch the positive side of the battery to anything with the ground still connected the potential is there to get a shock or fry electrical systems.
Bill
