B1981

Code

Other B — Body

Memory Off Switch Circuit Short to Battery

Brand: Other

Type: B — Body

Views: UK: 33 EN: 76 RU: 27

AI status

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Page language: EN

Causes

Short in the switch feed wire to constant battery voltage (pin shorted to B+)
Faulty Memory Off Switch that internally shorts to battery
Damaged or chafed wiring harness contacting a constant 12V source
Corroded or bridged connector pins allowing B+ to feed the circuit
Aftermarket equipment or previous repair incorrectly tied into a constant power feed
Internal failure in the control module reporting the circuit incorrectly

Symptoms

Memory functions (seat/mirror/steering memory) won’t disable/enable correctly
Stored B1981 fault and possibly other related body codes
Intermittent or constant battery drain with vehicle off
Inability to toggle memory switch or switch always reads ON
Related features operating erratically or disabled

What to check

Read and record all stored DTCs and freeze-frame data with a scan tool
Visual inspection of switch, harness, and connectors for damage, corrosion, or melted insulation
Check fuses and fusible links related to memory and body circuits
Backprobe switch connector and measure voltage with switch OFF and ON
Disconnect switch connector and check for battery voltage on the circuit pin (should not be present when harness isolated)
Perform an isolation test: disconnect connectors along the circuit to locate where B+ appears

Signal parameters

Expected: Switch circuit OFF = low impedance to module input, no battery voltage present at module pin (0 V or open depending on design)
Expected: Switch ON = ~12 V present (approx. 11–14 V depending on battery/charging)
Fault condition (short to battery): ~11–14 V present on switch circuit even when switch OFF
Resistance: with battery disconnected, open-circuit or high resistance between switch circuit and battery positive when harness isolated; low resistance if shorted

Diagnostic algorithm

Record DTC(s) and key-on/key-off data. Confirm B1981 is current or intermittent.
Obtain factory wiring diagram to identify switch, module pin, fuses, and splice points for the Memory Off Switch circuit.
Visually inspect the switch, connectors, and routing of the harness for physical damage, rodent chewing, corrosion, or aftermarket taps.
With ignition OFF, disconnect the switch connector. Using a DVOM, check for battery voltage on the switch circuit pin at the harness side. If voltage present with connector disconnected, the short is downstream of the switch (toward B+).
If voltage is present, isolate by disconnecting connectors/splices along the circuit (module connector, splice points) until voltage disappears—this locates the shorted section.
If no voltage at harness with switch disconnected, backprobe at the switch and operate the switch; verify the switch shows battery voltage only when ON. Replace switch if it shows battery when OFF.
Check continuity/resistance between the switch circuit and battery positive with battery removed. Low resistance indicates a short to B+. Also check continuity to adjacent circuits that share B+ for possible backfeed.
Inspect and repair any damaged wiring, replace corroded connectors, repair splices per OEM procedures, or replace the faulty switch.
If wiring and switch test OK, test the control module input. Re-check DTCs after repairs; if B1981 returns and wiring is confirmed good, consider module fault and follow manufacturer procedures for module testing/repair or replacement.
Clear DTCs and perform functional test of memory features and switch; monitor for reoccurrence and check for parasitic draw if battery drain was present.

Likely causes

Wiring short to battery at or near the switch connector
Failed Memory Off Switch (internally shorted)
Connector corrosion or pin damage at switch or module
Incorrect aftermarket accessory wiring
Module input driver fault (less common)

Fault status

⚠️ Status

Memory Off Switch circuit is detecting a short to battery voltage. The module senses battery voltage on the switch line when it should be low/open; diagnostic trouble code stored.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours