clear ecm/pcm error message

[OLDS75DK]

I repleaced the tcc ( torque converter clutch) solenoid circuit in 96 olds cierra 3.1 w/4T60E tranny. After reset the error code p1864 will not stay cleared more than 4 seconds before it pops up again on my Matco obd II scanner. any ideas on how to reset and clear code for good? do you think the pcm is bad. Please help if you can.

olds75dk

[maxwedge]

Check for power on the pink wire at the trans connector, make sure the connector is properly secured, no pins bent.

[Tech II]

Like Max is alluding to, a big mistake by DIY'ers, and even some techs is, when a code is set, it doesn't mean replace the part the code is named after.....

P1864, is for the TCC circuit.... that means anything in the circuit can cause this to happen......that includes the TCC solenoid, the wiring and connections to it, the PCM, AND the hydraulic circuit it controls......

So you may have replaced the solenoid, but how do you know the circuit is ok.....you could have an opening in a wire....you could have a bad PCM(rare)....or the hydraulic circuit could be plugged somehow....

This is why diagnosis is so important in cases like this......I have seen people replace transmissions, when all it was was a broken wire in a harness....

Most techs take a test drive with a scan tool, and observe if the PCM is commanding the TCC on, and if it is, if there is a drop in slippage when this occurs.....that is the basic first step in diagnosis....

As Max said, you need a scan tool capable of commanding the solenoid on and off.....you disconnect the harness to the tranny, attach a test light to the appropriate circuit in the harness, and then you command the solenoid on/off with the scan tool, and see if the light goes on/off.....if it does, then the problem is in the tranny....if it doesn't then the problem is the wiring harness or PCM....

Now if the light goes on off, you take the side cover off disconnect the TCC solenoid, reconnect the tranny harness and attach the test light to the TCC solenoid, and command the TCC on/off with the scan tool.....if it goes on/off, this eliminates the internal wiring harness.....then you install the new Solenoid....you can even command the solenoid on/off to hear/feel it click before putting the side cover back on.....

Now if that doesn't fix the problem, it's an internal tranny problem.....a circuit could be plugged, or you have a bad torque converter....

[OLDS75DK]

tech11 thanks for the info,il try it and get back to you;