rollingthunder1994 Posted June 26, 2004 Report Share Posted June 26, 2004 Hi All, The transmission on my 94 STS Seville is stuck in 2nd limp home mode. I replaced both shift solenoids, and the VSS sensor, because these are the codes i was getting. The transmission is still stuck in the limp home mode and the codes, i'm getting now are po52 PCM Memory reset, p109 Keep Alive Memory, IO52 Keep Alive Memory Error, TO73 PCM-EBTCM/EBCM Pulse width Modulation signal fault. Is there something that i have to do to the PCM to get the transmission out of the limp home mode? If so, where is the PCM located? BTW my tranny is the 4t80e. Any help will be greatly appreciated. Link to comment Share on other sites More sharing options...
TDK Posted June 26, 2004 Report Share Posted June 26, 2004 I'm no expert, but perhaps if you disconnected the battery for a few minutes, the codes might clear? This is not the same as clearing codes via the DIC. With any amount of luck, it may hard-reset some of the electro-mechanical, sensors and sub-systems. This procedure has been mentioned for to get the AC going enough to recharge when low. Maybe the tranny codes won't clear automatically, without a little help. Can't hurt I don't think, but you will get some standard re-set codes regardless. Good Luck Add power to leave problems behind. Most braking is just - poor planning. Link to comment Share on other sites More sharing options...
navion Posted June 27, 2004 Report Share Posted June 27, 2004 rollingthunder1994, Try to clear the PCM codes by the following proceedure: Enter diagnostics and wait until it displays "PCM DATA" press "LO". "PCM INPUTS?" appears, press "LO" again. "PCM OUTPUTS?" appears, press "LO", "PCM OVERRIDE?" appears, press "LO", "PCM CLEAR CODES?' appears, Press HI and hold down until "PCM CODES CLEAR" appears. After 3 seconds the display will go to "PCM SNAPSHOT" If you press "LO" again, you will be back at "PCM DATA?" Exit the diagnostic mode and then drive the car and see if it has helped your situation. Good Luck Britt PS: Did you find that the "A" and "B" solenoids were bad? Your post states that you changed them. Did you perform a continuity/resistance on the coils? If so what were the readings? Were the checkballs reinstalled in their proper places? Please let me know shat you find, as I have the same problem with my 1994 SLS. Britt Link to comment Share on other sites More sharing options...
32v_dohc Posted June 28, 2004 Report Share Posted June 28, 2004 Those codes are usually caused by a loose PCM connector or an improperly install MEM-CAL. HTH John Link to comment Share on other sites More sharing options...
Logan Posted June 29, 2004 Report Share Posted June 29, 2004 PO52 and PO109 are the same code. They are both listed under PO109. Common code during a battery reset. Typically normal and ignore. IF the PO52 and PO109 are popping on a regular basis.....check the battery cables for loose, corrosion issues.......OR....could be........It could be a bad PCM quad driver....its about that time....also there were some funky '94 PCMs floating around. I think there is a GM TSB on the '94s PCMs. The PCM is a silver box, mounted on the firewall, inside the car behind the glovebox bucket. Maybe $150 exchange at DELCO. Maybe as cheap as $80 at AutoZone. Cadillacs are very sensitive to good battery connections. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
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