I have a 2001 S10 that is throwing P1860 and P1870 codes. I've searched the web and found that the harness and solenoid can be tested but I can't find specifics for this make/year. From what I've read it seems like the usual suspect is the solenoid, but I'd like to test everything else before opening the transmission up. Can some one help me with where I can test from? Location of connectors and pin outs would be great. I've never done any transmission work before, so this is new to me.

thanks in advance
mike

 

i found this out about the 1860 code....


1. Disconnect the PCM red connector.

2. Connect and ammeter from pin 7, Brown wire to ground.

3. Key On Engine Off (KOEO), check amp draw of the TCC Pulse Width Modulation (PWM) solenoid.

4. Should have 0.8 to 1.3 amps.

5. If OK, check after 15 minutes of current flow.

6. If the amp draw is high, replace the solenoid.

7. If the amp draw is low, check available voltage to the transmission at pin E, Pink wire, while the ammeter is still connected and loading the circuit.

8. Should have 11-12 V at pin E.

9. If the amp draw is low and the voltage at pin E is OK, replace the TCC PWM solenoid.

10. If the amp draw is OK, replace the PCM.


Potential Causes
Failed Ignition Switch
Failed Torque Converter Clutch (TCC) Pulse Width Modulation (PWM) Solenoid
Broken Transmission Wiring



Confirmed Fix
4 - Replaced Vehicle Control Module (VCM)
3 - Replaced Torque Converter Clutch (TCC) Pulse Width Modulation (PWM) Solenoid
1 - Replaced Automatic Transmission

 

P1860 is an electrical code for the TCC PWM solenoid. With both codes I would go after the P1860 code first. The bad solenoid can and and will cause a TCC slip forcing a P1870 code. If never goes away it's time for a Valve Body repair or replacement. Follow Abig84 post for checking the electrical. You should fix it with that.