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Technical Service Information
N88 Solenoid (No. 1 Solenoid)
The N88 Solenoid is an On/Off solenoid and is On and Open in gears 4th through 6th. If this solenoid fails in
the Closed (Off) position, 4th through 6th gear will not be available.
N89 Solenoid (No. 2 Solenoid)
The N89 Solenoid is also an On/Off solenoid and is On and Open, to allow a line pressure increase when the
torque converter clutch is applied. When both the N88 and N89 solenoids are energized at the same time, the
B2 brake clutch is applied in Tiptronic 1st Gear (Manual Low). If the N89 Solenoid fails in the Closed (Off )
position, there will be no pressure increase in TCC and no engine braking in Tiptronic 1st gear (Manual
Low).
N90 Solenoid (No. 3 Solenoid)
The N90 Solenoid is a normally applied, pulse width modulated solenoid controlling the apply and release
of the K3 Clutch. When this solenoid is fully Off, the K3 clutch is fully applied. If this solenoid fails in the
Off (Normally Applied) position, there will be 3rd gear starts and Reverse application may be firm.
N91 Solenoid (No. 4 Solenoid)
The N91 Solenoid is a normally vented, pulse width modulated solenoid controlling the apply and release of
the converter clutch, with the ability to ramp the apply and release. When this solenoid is fully Off, the
converter clutch is fully released. If this solenoid fails in the Off (Normally Vented) position, there will be no
converter clutch application.
Solenoid N92 (No. 5 Solenoid)
The N92 Solenoid is a normally applied, pulse width modulated solenoid controlling the apply and release
of the K1 Clutch. When this solenoid is fully Off, the K1 clutch is fully applied. If this solenoid fails in the
Off (Normally Applied) position, Drive engagement will be firm, and there will be a bind in 5th.
Solenoid N93 (No. 6 Solenoid)
The N93 Solenoid is a normally applied, pulse width modulated solenoid and controls the main line
pressure. When this solenoid is fully Off, maximum line pressure is the result. If this solenoid fails in the Off
(Normally Applied) position, all shifts will be harsh.
Solenoid N282 (No. 9 Solenoid)
The N282 Solenoid is a normally applied, pulse width modulated solenoid controlling the apply and release
of the K2 Clutch. When this solenoid is fully Off, the K2 clutch is fully applied. If this solenoid fails in the
Off (Normally Applied) position, 4th shift may be firm.
Solenoid N283 (No. 10 Solenoid)
The N283 Solenoid is a normally applied, pulse width modulated solenoid controlling the apply and release
of the B1 Clutch. When this solenoid is fully Off, the B1 clutch is fully applied. If this solenoid fails in the Off
(Normally Applied) position, there may be 2nd gear starts..
INDIVIDUAL SOLENOID FUNCTION AND RESULT OF FAILURE
Figure 13
Note: Refer to Figure 14 for Solenoid Application chart and Clutch Application chart for each gear. You
will also find an observed Amperage chart from the actual vehicle that you can use for comparison. This
should make the diagnosis process much easier for the vehicle that you are repairing.