Make and Model > GMC Trucks > Acadia > P182E, hard shift, no PRNDL display — Internal Mode Switch

P182E, hard shift, no PRNDL display — Internal Mode Switch

Diagnose and fix P182E, hard shift, no PRNDL display

A P182E, hard shift, no PRNDL display condition on the vehicles listed below can be caused by a faulty internal mode switch. The internal mode switch is the new name for what we used to call the park/neutral switch, which was then changed to transmission range selector.

P182E: Internal Mode Switch Indicates Invalid Range

The IMS does not indicate a valid Park, Reverse, Neutral, or Drive Range position for 7 seconds.

How the internal mode switch works

The switch has a sliding contact switch attached to the shift detent lever shaft inside the transmission. The switch sends 4 inputs to the transmission control module (TCM) to indicate which gear position is selected by the transmission driver. The input voltage at the TCM is high when the switch is open and low when the switch is closed to ground. The state of each input is displayed on the scan tool as IMS. The IMS input parameters represented are transmission range Signal A, Signal B, Signal C, and Signal P.

The P182E code can only set if:

The engine speed is 400 RPM or greater for 5 seconds.

The ignition voltage is 9.0 volts or greater.

Codes P0101, P0102, P0103, P0106, P0107, P0108, P0171, P0172, P0174, P0175, P0201, P0202, P0203,

P0204, P0205, P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307,

P0308, P0401, P042E, P0722, or P0723 is not set.

A faulty internal mode switch may cause the check engine light to illuminate and store a P183E trouble code. In some cases the PRNDL display stops working because the transmission control module can’t figure out what gear you’ve selected. It can also cause hard shifting, again because it’s confused about which gear you’ve selected.

What happens when P182E sets

The TCM commands maximum line pressure.

The TCM turns OFF all solenoids.

The TCM freezes transmission adaptive functions.

The TCM limits the transmission to reverse and 5th gear.

The TCM forces the torque converter clutch (TCC) OFF.

The TCM inhibits the Tap Up/Tap Down function.

The TCM inhibits manual shifting of forward gears.

The TCM turns the high side driver OFF.

The TCM enables torque management.

GM has issued a technical service bulletin PI0269B to address the issue

Vehicles affected by PIO269B P182E

2009-2011 Buick Enclave

2010-2011 Buick LaCrosse

2010-2011 Cadillac SRX

2009-2011 Chevrolet Equinox, Malibu, Traverse

2009-2011 GMC Acadia

2010-2011 GMC Terrain

2009 Pontiac G6, Torrent

2009-2010 Saturn AURA, OUTLOOK, VUE

Equipped with 6T70, 6T75 Automatic Transmission and built from February, 2009 through July, 2010

Fix P182E

Start by checking the shift cable adjustment

• Set the park brake and chock the wheels.

• Verify the transmission range select lever is in the park position.

• Verify the transmission manual shift lever is in the park position.

• At the transmission, pull the retaining collar forward on the shift cable. Then release the range select cable adjuster clip

• Then slide the two halves of the range select cable together until all free play is removed.

Depress the adjuster clip to lock the adjuster clip completely, then release the retaining collar.

Pull both halves of the range select cable in opposite directions to verify the cable adjuster is secured. Check the transmission range select lever in all gear selections for proper operation.

Verify the park/neutral status in all ranges

Check the PRNDL display to see if it works and shows the proper gear selection. If no display, check gear status on a scan tool.

Replace the internal mode switch

If the adjustment doesn’t solve the problem,

Internal mode switch

replace the internal mode switch. The internal mode switch is a complete unit (lever, manual shift detent with shaft position switch assembly.

For PDF instructions, see this post

For a really bad you tube video, see this:

Posted on December 22, 2017 by Rick Muscoplat