Patient monitors · BIS family

Aspect Medical Systems BIS VISTA: troubleshooting and error codes

The ServiceForge knowledge base holds 21 documented symptoms for the Aspect Medical Systems BIS VISTA, with 44 ranked causes, 26 diagnostic checks with test points and expected values, and 58 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Excessive artifact in signal

Signal quality below half of optimal level; artifact from motion, eye blinks, or electromagnetic interference reducing EEG recognition

Ranked causes

1. Patient motion or eye blinks (common)
2. Electrical activity (EMG) interfering with EEG (common)
3. Electro-cautery or warming blankets (occasional)
4. Defective PIC (occasional)
5. Defective BISx (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Sensor check failed

Last sensor check failed or was exited before completion, impedance too high or sensor not properly applied

Ranked causes

1. Electrode impedance too high before sensor check completed (common)
2. Incorrect sensor application (common)
3. Poor sensor connection (occasional)
4. Defective PIC (occasional)
5. Defective BISx (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Sensor disconnected or not recognized

System displays sensor disconnection message, unable to detect sensor or cable connection

Ranked causes

1. Sensor physically disconnected (common)
2. Poor or contaminated connection between sensor and PIC (common)
3. Disconnected PIC (occasional)
4. Defective PIC (occasional)
5. Defective BISx (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

BISx not recognized

Monitor displays 'Connect BISx' message, BISx fails to respond to communication attempts

Ranked causes

1. BISx disconnected or loose connection (common)
2. Defective Monitor Interface Cable (common)
3. Defective BISx (occasional)
4. Defective monitor (rare)

First check

Run DSC Self Test with no sensor connected

Expected: PASS

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Electrode not in contact

System displays press electrode(s) message, indicating one or more electrodes not reading properly

Ranked causes

1. Sensor not fully in contact with patient skin (common)
2. Incorrect sensor application (common)
3. Defective PIC (occasional)
4. Defective BISx (occasional)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Poor signal quality, no BIS value available

Signal quality too low to accurately calculate BIS value; BIS value and related trend variables not displayed

Ranked causes

1. Patient motion or eye blinks (common)
2. Electrical activity (EMG) interfering with EEG (common)
3. Defective PIC (occasional)
4. Defective BISx (rare)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Suspected BISx cable fault caution

BISx not recognized by monitor; determine which cable is defective using diagnostic isolation procedure

Ranked causes

1. Monitor Interface Cable defective (common)
2. Patient Interface Cable (PIC) defective (occasional)
3. BISx or BISx Bulkhead Connector defective (rare)

First check

With no sensor connected, run DSC Self Test

Expected: Test indicates PASS

1 more check with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Automatic background diagnostics detects fault during operation patient safety

Continuous runtime diagnostics detect interface fault, lead disconnect, lead-off condition, or power fault

Ranked causes

1. BISx sensor interface disconnection; lead disconnection; lead-off condition; power supply fault (common)

First check

Inspect sensor cable connection to BISx

Test point: BISx sensor connector
Expected: Connector fully seated, no visible corrosion or damage

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

BIS monitoring system requires checkout and safety verification patient safety

Routine safety and functionality testing including DSC self test, PIC checkout, leakage test and optional Hipot test

Ranked causes

1. Routine maintenance and safety verification required (common)

First check

Perform DSC Self Test

Test point: Monitor interface
Expected: All test sections show PASS status

5 more checks with pass and fail actions, 7 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

BIS value out of target range

BIS measurement has fallen outside the user-configured target range, either too high or too low

Ranked causes

1. Patient condition change (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

BISx Checkout and Safety Tests patient safety

Comprehensive system verification including DSC self-test, PIC checkout, and electrical safety testing

Ranked causes

1. System verification and safety validation required (common)

7 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Calibration: Touch Screen

Touch screen requires recalibration to ensure accurate input response

Ranked causes

1. Touch screen calibration drift or inaccuracy (occasional)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Manual diagnostic test failure during DSC self-test patient safety

Operator-initiated manual diagnostics report digital signal converter (DSC) circuit malfunction

Ranked causes

1. DSC analog-to-digital converter circuit fault; electro-cautery interference during test (occasional)

First check

Verify no electro-cautery or high-EMI equipment operating

Test point: Operating room environment; monitor display
Expected: No RF/electro-surgical activity detected by monitor

2 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Replace BISx bulkhead connector

BISx unit bulkhead connector requires replacement due to damage or connector failure

Ranked causes

1. Bulkhead connector damage or failure (occasional)

First check

Disconnect BISx from monitor and remove Patient Interface Cable

Test point: BISx and PIC connectors
Expected: BISx and PIC fully disconnected from monitor

5 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Replace BISx or BISx4

BIS signal processor unit requires replacement due to damage or malfunction

Ranked causes

1. BISx unit damage or failure (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Replace monitor

BIS VISTA monitor unit requires replacement due to damage, display failure, or malfunction

Ranked causes

1. Monitor damage or failure (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Replace monitor interface cable

BISx to monitor interface cable requires replacement due to damage or connector failure

Ranked causes

1. Cable damage or connector failure (occasional)

First check

Disconnect BISx from monitor

Test point: BISx connector
Expected: BISx disconnected from monitor interface port

5 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Replace PIC or PIC-4 cable

Patient Interface Cable requires replacement due to damage or failure

Ranked causes

1. PIC cable damage or failure (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Software malfunction or unresponsive display

Monitor software becomes unresponsive or display freezes; reset button accessible on rear panel

Ranked causes

1. Software fault requiring reset (occasional)

First check

Locate Reset button on back panel

Test point: Back panel
Expected: Reset button accessible with pointed tool

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

System failure or malfunction detected on power-up

Power-up diagnostics detect software image corruption, trend data corruption, or hardware fault during initial startup

Ranked causes

1. Software image checksum error; trend data memory corruption; hardware interface fault (rare)

First check

Allow power-up diagnostics to complete

Test point: System display and status indicators
Expected: Diagnostics complete without error; unit enters normal operation or displays failure message

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Touch screen requires calibration

Touch screen may need recalibration if responsiveness or accuracy degrades from factory settings

Ranked causes

1. Factory calibration lost or degraded (rare)

First check

Select Calibrate Touch Screen option

Test point: Maintenance Menu
Expected: On-screen calibration instructions appear

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`01`	Connect BISx	BISx disconnected or not recognized by monitor	warning
`1000-1999`	Unrecoverable BISx Error	Fatal error in BISx or BISx-monitor interface	critical
`[1000-1999]`	Unrecoverable BISx error / BISx initialization error	BISx hardware or initialization failure	critical
`109`	Sensor Used for Over 24 Hours	Sensor has been continuously connected for more than 24 hours	info
`[109]`	Sensor used for over 24 hours	Sensor attachment duration exceeds 24 hours	warning
`13`	Re-prep Sensor	Sensor application incorrect or not ready for use	warning
`14`	Sensor Disconnected	Sensor is disconnected or connection lost	warning
`16`	Last Sensor Check Failed	Sensor check did not complete or sensor element impedance too high	warning
`2000-2999`	Unrecoverable Monitor Error	Fatal system error has occurred in monitor hardware or software	critical
`[2000-2999]`	System error / Unrecoverable monitor error	System-level hardware or software failure	critical
`202`	Sensor Expired	Sensor expiration date passed or system time/date incorrect	warning
`27`	Excessive Artifact Detected in Signal	Signal quality less than half desirable level due to non-EEG artifact	warning
`28`	Data unavailable due to poor signal quality	Signal quality too low to calculate accurate BIS value	warning
`29`	BIS Out of Target Range - Low	BIS value fallen below user-set target range	info
`[2902]`	Hardware timer error	System timer hardware malfunction	critical
`30`	BIS Out of Target Range - High	BIS value risen above user-set target range	info
`[3000-3999]`	Data export error	Data export operation failed	error
`3000-3999`	Data Export Error	Data export to removable USB drive failed	error
`31`	Isoelectric EEG Detected	No discernible EEG activity for several minutes; SR=100	warning
`[31]`	Isoelectric EEG detected	No discernible EEG activity detected for 63 seconds	info
`[33]`	Operating on battery backup	AC power loss; monitor switches to battery	warning
`33`	Operating On Battery Backup	AC power lost; monitor running on internal battery	warning
`[34]`	Battery power low	Battery charge depleted to critical level	critical
`34`	Battery Power Low	Battery charge reduced to only few minutes remaining	warning
`4000-4999`	Software Update Error	Software update did not complete successfully	error
`[4001-4999]`	Unable to update software	Software update or upgrade operation failed	error
`[471]`	Unrecoverable monitor error	Monitor unplugged during software upgrade or battery exhaustion during operation	critical
`[5000-5999]`	Trend memory error	Trend data memory failure or corruption	error
`5000-5999`	Trend Memory Error	Memory error detected in trend data storage system	critical
`[512]`	Data export error	Data export operation failed	error
`[513]`	Date and time not changed	Attempted to change system date/time while case in progress	warning
`[516]`	Trend memory error	Trend memory full or data corruption detected	error
`[517]`	Unrecoverable BISx error	BISx hardware or initialization failure	critical
`[524]`	No data available	No case data exists or data is inaccessible	warning
`[527]`	PDF creation halted: USB error	USB drive error during PDF export	error
`[533]`	System error	Generic system error condition	error
`[537]`	Snapshot corrupted	Snapshot file corruption detected	error
`[538]`	System error	Generic system error condition	error
`[539]`	Export halted: USB drive not detected	USB drive not recognized by monitor	error
`[540]`	Export halted: USB drive full	USB drive storage capacity exceeded	error
`[541]`	Export halted: BISx not detected	BISx disconnected or communication lost during export	critical
`[544]`	Export halted: USB drive full	USB drive storage capacity exceeded	error
`[545]`	Export halted: USB drive not detected	USB drive not recognized by monitor	error
`[548]`	Replace PIC - possible PIC problem	PIC or Sensor Simulator failure detected	error
`[549]`	Possible PIC problem - check cable using Sensor Simulator	PIC or cable fault suspected	error
`6000-6999`	Snapshot Error	Snapshot capture or storage process did not complete correctly	error
`[6000-6999]`	Snapshot error	Snapshot data capture or processing failed	error
`[83]`	Sensor incompatible with monitor	Sensor type does not match monitor configuration	error
`[92]`	Sensor ground fault (negative)	Detected ground fault on sensor negative lead	error
`92`	Sensor Ground Fault	Problem detected in sensor ground electrode circuit	warning
`[93]`	Sensor ground fault (positive)	Detected ground fault on sensor positive lead	error
`93`	Sensor Ground Fault	Problem detected in sensor ground electrode circuit (alternate code)	warning
`94`	Sensor Overcurrent	Sensor is drawing excessive current	warning
`[94]`	Sensor overcurrent	Sensor current draw exceeds safe limits	error
`[95]`	Sensor unusable - connection limit reached	Sensor connected and disconnected too many times	error
`95`	No more Uses for this Sensor	Sensor has been connected and disconnected too many times	info
`96`	Sensor Invalid	Sensor not recognized or rejected by system	warning
`[96]`	Reinsert sensor firmly	Poor or loose sensor connection detected	warning

Likely causes and actions for each code are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.