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1886
CIRCUIT DESCRIPTION
The 3-2 Shift Solenoid Valve Assembly (3-2 SS Valve Assy.) Is a normally-closed, 3-port, on/off device that controls the 3-2 downshift. The solenoid attaches to the control valve body within the transmission. The solenoid receives ignition voltage through circuit 1020. The Vehicle Control Module (VCM) controls the solenoid by providing a ground path on circuit 687. During a 3-2 downshift, the 2-4 band applies as the 3-4 clutch releases. The VCM varies the timing between the 3-4 clutch release and the 2-4 band apply depending on the vehicle speed and the throttle position.
When the VCM detects a continuous open or short to ground in the 3-2 SS Valve Assy. Circuit or the 3-2 SS Valve Assy, then DTC P1886 sets. DTC P1886 is a type A DTC.
CONDITIONS FOR SETTING THE DTC
The system voltage is 10-17 volts.
The engine is running.
All of the above conditions are met for 5 seconds, and either of the following fail conditions occurs for 5 seconds:
The VCM commands the solenoid ON and the voltage remains high (B+).
The VCM commands the solenoid OFF and the voltage remains low (0 volts).
ACTION TAKEN WHEN THE DTC SETS
The VCM commands a soft landing to third gear.
The VCM commands maximum line pressure.
The VCM freezes shift adapts from being updated.
The VCM inhibits TCC engagement.
The VCM inhibits 4th gear if the transmission is in hot mode.
The VCM illuminates the Malfunction Indicator Lamp (MIL).
CONDITIONS FOR CLEARING THE MIL/DTC
The VCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.
A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported.
The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM.
DIAGNOSTIC AIDS
Inspect the wiring for poor electrical connections at the VCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look for the following conditions:
A bent terminal.
A backed out terminal.
A damaged terminal.
Poor terminal tension.
A chafed wire.
A broken wire inside the insulation.
When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
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