• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
B+, MSM Terminal F11 X2 | B1420 | B1420 | -- | -- |
B+, Seat Adjuster Switch | B1420 | 1 | -- | -- |
B+, Memory Seat Adjuster Switch | B1420 | 2 | -- | -- |
Power Seat Front Vertical Up Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Power Seat Front Vertical Down Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Power Seat Horizontal Rearward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Power Seat Horizontal Forward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Power Seat Recline Forward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Power Seat Recline Rearward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Power Seat Rear Vertical Up Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
Power Seat Rear Vertical Down Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820 | -- |
1. Power seat inoperative 2. Memory seat functions inoperative |
Battery positive voltage is supplied at all times to the memory seat module (MSM), the driver seat adjuster switch, and the memory seat adjuster switch from the TILT/TELE SW/MEM SEAT MOD 10A fuse located in the body control module (BCM) fuse block. The MSM monitors this voltage to verify that power is supplied to the seat adjuster switch before it will allow for any memory recall operation.
• | DTC B1327 must not be present. |
• | Battery voltage must be between 9-16 volts. |
DTC B1420 will set if the MSM detects an open on the B+ circuit.
• | The memory seat functions for the seat will be disabled. |
• | Manual seat functions will operate. |
• | The condition responsible for setting the DTC no longer exists. |
• | A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred. |
The MSM is also referred to as the Driver Position Module in certain scan tool menus.
Memory Seats Description and Operation
Control Module References for scan tool information
Ignition ON, observe the scan tool Driver Position Module seat switch parameters while activating each switch. The reading should change between Inactive and Active as each switch is activated.
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for MSM replacement, setup, and programming