Conditions For Setting DTC P1860

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DTC will set if all conditions for running the DTC are met, and either of the following conditions occur for 4.3 out of 5 seconds.

The PCM commands the TCC PWM solenoid valve off (zero percent) and the voltage input remains low (zero volts).
The PCM commands the TCC PWM solenoid valve on (100 percent) and the voltage input remains high (battery voltage).