On Call Plus Error Codes E0–E6 & Troubleshooting Guide

On Call Plus glucometer E0 E1 E2 E3 E4 E5 E6 error codes and troubleshooting guide

If your On Call Plus glucometer displays an error such as E0, E1, E2, E3, E4, E5 or E6, the message can help identify what went wrong during meter startup, strip handling, blood application, calibration or battery operation.

The On Call Plus meter also displays other messages for temperature problems, code-chip faults, incorrect test strips, battery condition and glucose results outside the meter's measurement range.

This guide explains the main On Call Plus error codes and troubleshooting steps and helps you decide when to repeat the test, replace the strip, check the code chip, replace the battery or seek additional support.

For complete information about the meter, compatible strips, coding and pack sizes, first see our On Call Plus Glucometer & Test Strips Complete Guide .

On Call Plus Error Codes: Quick Reference

Display	Likely Cause	What to Do
E-0	Power-on self-check error	Remove the battery for about 30 seconds, reinstall it and restart the meter.
E-1	Internal calibration check error	Move the meter away from strong electrical or radio-frequency sources and retry.
E-2	Test strip removed during testing	Repeat the test with the strip left fully inserted until testing is complete.
E-3	Blood or control sample applied too early	Use a new strip and wait for the blood-drop/test-strip symbol before applying sample.
E-4	Used, damaged or contaminated test strip	Discard the strip and repeat with a new compatible On Call Plus strip.
E-5	Insufficient blood sample	Repeat with a fresh strip and apply enough blood to correctly fill the strip check window.
E-6	Battery too low to continue testing	Replace the battery and repeat the test.

Important: Do not reuse the same test strip when the troubleshooting instructions require a new strip.

On Call Plus E0 Error – Power-On Self-Check Error

E-0, sometimes searched as E0 or On Call Plus error 0, indicates that the meter encountered a problem during its power-on self-check.

What to do for E0

Turn the meter off.
Remove the battery.
Wait approximately 30 seconds.
Reinstall the battery correctly.
Turn the meter on again.

If E-0 repeatedly returns after the battery reset, discontinue repeated testing with additional strips and seek product or technical support.

On Call Plus E1 Error – Internal Calibration Check Error

E-1 indicates an internal calibration-check problem.

Strong radio-frequency or electrical interference near the meter can contribute to this type of problem.

What to do for E1

Move mobile phones away from the meter during testing.
Move away from strong radio-frequency sources.
Avoid testing immediately beside high-powered electrical equipment.
Restart the testing procedure.

If E-1 continues to appear after moving the meter away from possible interference sources, stop repeatedly using test strips and obtain technical support.

On Call Plus E2 Error – Test Strip Removed During Test

E-2 means the test strip was removed or lost proper contact with the meter while the test was in progress.

How to fix E2

Discard the interrupted test strip.
Insert a new compatible On Call Plus strip fully into the strip port.
Keep the strip in place throughout the test.
Do not pull, move or partially remove the strip while the meter is counting down.

If E-2 occurs repeatedly even when the strip remains properly inserted, inspect the strip port for visible contamination or damage and seek support if necessary.

On Call Plus E3 Error – Blood Applied Too Early

E-3 occurs when the blood or control sample is applied to the test strip before the meter is ready to accept the sample.

After inserting the strip, wait until the meter displays the appropriate blood-drop/test-strip symbol before applying blood.

How to correct E3

Discard the strip used during the failed test.
Insert a new On Call Plus Test Strip.
Wait for the meter's sample-ready indication.
Only then apply the blood sample.

For the complete testing sequence, see:

How to Use On Call Plus Glucometer & Test Strips →

On Call Plus E4 Error – Used or Contaminated Test Strip

E-4 generally indicates that the meter has detected a strip that is already used, contaminated or otherwise unsuitable for testing.

What to do for E4

Discard the affected strip and perform the test using a new compatible On Call Plus Test Strip.

Do not attempt to:

reuse a previously tested strip,
clean a used strip,
apply blood to a strip that has already been exposed or contaminated, or
insert a visibly damaged strip.

If unused strips repeatedly produce E-4, check:

strip expiry,
storage conditions,
whether the strip container has been kept properly closed,
whether the strips were exposed to moisture or contamination, and
whether the strips are genuinely compatible with On Call Plus.

For storage information, read:

On Call Plus Test Strips Expiry & Storage Guide →

On Call Plus E5 Error – Insufficient Blood Sample

E-5 means the strip did not receive enough sample to complete the measurement correctly.

The On Call Plus system requires approximately 1 µL of blood. The strip sample area must fill as instructed by the manufacturer.

How to fix E5

Discard the strip from the failed test.
Prepare a new compatible strip.
Obtain an adequate blood drop.
Apply the sample to the correct sample area.
Make sure the strip's check window fills as instructed.

Do not assume that repeatedly adding blood to a failed Plus test will correct E-5. Follow the Plus-specific testing instructions and use a fresh strip when required.

On Call Plus E6 Error – Battery Too Low

E-6 means the battery has discharged to the point that the meter will not allow further glucose testing.

Replace the battery before attempting another test.

On Call Plus battery type

The traditional On Call Plus meter uses a CR2032 3V coin-cell battery.

After replacing the battery

Ensure the battery polarity is correct.
Close the battery compartment securely.
Check the meter date and time.
Repeat the glucose test using a fresh strip.

Low-Battery Symbol vs E6

A low-battery symbol can appear before the battery is completely unable to support another test.

If the meter still has sufficient power, testing may temporarily remain possible, but the battery should be replaced promptly.

Once E-6 appears because the battery cannot support another test, replace the battery before continuing.

On Call Plus HI Message – What Does It Mean?

The On Call Plus measurement range is approximately 20–600 mg/dL.

If the meter displays HI, the measured glucose concentration is above the meter's reportable range, meaning it is greater than approximately 600 mg/dL.

This is not the same as an ordinary E-code error.

What to do if On Call Plus displays HI

Wash and thoroughly dry your hands.
Repeat the test with a new compatible strip to rule out a testing-procedure problem.
If HI is repeated, follow the meter instructions and seek prompt medical advice.

A repeatedly confirmed HI reading represents a potentially very high glucose level and should not be ignored.

On Call Plus LO Message – What Does It Mean?

If LO appears on the display, the measured glucose concentration is below the meter's reportable range of approximately 20 mg/dL.

What to do if On Call Plus displays LO

Repeat the test with a fresh strip if this can be done safely and without delaying necessary treatment.
If LO is confirmed or symptoms of severe low glucose are present, follow the hypoglycaemia treatment plan provided by your healthcare professional.
Seek urgent medical assistance when severe symptoms, altered consciousness or inability to self-treat are present.

Do not dismiss a repeated LO result as simply a meter fault without appropriate assessment.

HI / LO vs HI t / LO t – Do Not Confuse Them

On Call Plus uses different displays for glucose-range messages and operating temperature warnings.

Display	Meaning
HI	Glucose result above the meter's measurable range
LO	Glucose result below the meter's measurable range
HI t	Meter/system temperature is above its permitted operating range
LO t	Meter/system temperature is below its permitted operating range

A temperature warning does not mean that your blood glucose itself is high or low.

On Call Plus HI t – Meter Too Hot

A high-temperature warning indicates that the meter or testing environment is above the system's permitted operating temperature.

Move the meter to a cooler suitable environment and allow it to stabilise before repeating the test.

Do not attempt to rapidly cool the meter using a refrigerator, freezer or direct contact with ice.

On Call Plus LO t – Meter Too Cold

A low-temperature warning indicates that the meter is below the system's permitted operating temperature.

Move the meter to a warmer suitable environment and allow it to reach an appropriate operating temperature before testing again.

If the meter itself fails to power on after being stored in very cold conditions, the On Call Plus instructions recommend allowing it approximately 30 minutes to reach room temperature before retrying.

On Call Plus CODE Message – No Code Chip

If the meter displays CODE because no code chip is installed, insert the correct code chip supplied with the applicable box of On Call Plus Test Strips.

On Call Plus uses a code-chip based system, so the coding setup should be checked when changing strip supplies.

For a complete explanation, read:

On Call Plus Code Chip & Coding Guide →

On Call Plus E7 – Damaged or Removed Code Chip

E-7 is associated with a damaged code chip or a code chip that was removed during testing.

What to check

Make sure the chip is not visibly damaged.
Check that the chip remains installed during testing.
Confirm that its code corresponds to the applicable test-strip code.
If damaged, use the appropriate replacement code chip supplied for the strips.

On Call Plus E8 – Meter Electronics Failure

E-8 indicates an internal electronics problem.

If the error persists after restarting the meter, discontinue repeated testing with new strips and contact the appropriate product-support channel.

On Call Plus E9 – Incorrect Code Chip

E-9 indicates that the code chip installed in the meter is not the correct code chip for the On Call Plus testing system.

Check that:

you are using On Call Plus Test Strips,
the code chip belongs to the correct strip supply, and
you have not accidentally inserted a chip from another On Call system.

For detailed model compatibility, see:

On Call Plus Test Strip Compatibility Guide →

On Call Plus E10 – Data Communication Error

E-10 relates to a communication failure while transferring meter records to a compatible computer/data-management system.

This is a data-transfer problem rather than a blood-sample error. Check the applicable data-management connection and instructions.

On Call Plus Meter Will Not Turn On

If your On Call Plus meter does not power on at all, first check the simple causes before assuming that the meter has failed.

1. Check the battery

The battery may be discharged, damaged, incorrectly inserted or making poor contact.

Remove and reinstall the battery.
Confirm the polarity.
Try a new CR2032 battery if necessary.

2. Consider temperature

A meter stored in very cold conditions may not start normally. Allow it to reach a suitable room temperature before testing again.

3. Insert a test strip correctly

A correctly inserted new On Call Plus strip normally activates the testing sequence. Make sure the strip is inserted in the proper orientation.

4. If the meter remains completely unresponsive

Stop using additional strips while troubleshooting. A persistent power problem may require meter replacement or technical support.

On Call Plus Meter Is Not Reading the Test Strip

If you insert a strip but the meter does not recognise it, check the following:

Compatibility: Is it genuinely an On Call Plus Test Strip?
Orientation: Is the strip inserted correctly?
Insertion: Is it fully seated in the strip port?
Condition: Is the strip new, dry and undamaged?
Expiry: Is the strip within its applicable use-by period?
Code chip: Is the correct Plus code chip installed?
Battery: Does the meter have adequate power?
Strip port: Is there visible contamination or damage?

Do not force a strip into the meter.

On Call Plus Meter Reads the Strip but Will Not Start the Test

If the strip is recognised but testing does not begin after applying blood, possible causes include:

blood applied before the meter was ready,
insufficient sample volume,
blood applied to the wrong portion of the strip,
a used or contaminated strip,
incorrect strip family, or
an operating-temperature problem.

Note the exact message displayed by the meter before discarding the strip. The error number usually provides a more precise troubleshooting path.

On Call Plus Gives Unexpected Results – What Should You Check?

An unexpected reading does not automatically prove that the meter is defective. Before drawing conclusions, consider:

hand washing and drying,
correct strip compatibility,
strip storage and expiry,
correct code-chip setup,
adequate blood sample,
meter operating temperature,
possible contamination of the strip or meter port, and
whether a control solution check is appropriate.

If a result is inconsistent with how you feel, or remains unexpectedly high or low after correct repeat testing, seek appropriate medical advice rather than changing treatment based only on troubleshooting.

When Should You Perform a Control Solution Test?

A control solution test can help assess whether the meter and compatible strips are operating together as expected.

Refer to the manufacturer's instructions regarding control testing, particularly when:

you suspect strips may have been stored incorrectly,
the meter has been dropped or damaged,
results repeatedly appear unexpected, or
you want to check the meter-and-strip system.

Control solution results are quality-control checks and are not personal blood glucose measurements.

How to Reduce On Call Plus Testing Errors

Always use compatible On Call Plus Test Strips.
Check strip expiry before testing.
Store strips according to manufacturer instructions.
Keep vial-packed strips properly closed.
Keep foil-packed strips sealed until use.
Wait for the blood-drop symbol before applying blood.
Use an adequate sample.
Keep the strip inserted until testing finishes.
Use the correct code chip for the applicable strips.
Replace a weak battery promptly.
Do not test outside the permitted meter operating conditions.

On Call Plus vs On Call Extra Error Codes

Do not use this Plus guide to troubleshoot an On Call Extra meter.

Although the two systems share the On Call brand, their strip technology and operating features differ.

If your meter says On Call Extra, use:

On Call Extra Error Codes & Troubleshooting Guide →

For a complete comparison of the two systems:

On Call Plus vs On Call Extra Glucometer Comparison →

Need Compatible On Call Plus Test Strips?

Troubleshooting will not solve an incompatibility problem if the wrong strip family is being used.

Browse the complete range:

Shop On Call Plus Glucometers & Test Strips →

Frequently Asked Questions

What does E0 mean on an On Call Plus glucometer?

E-0 indicates a power-on self-check error. Remove the battery for approximately 30 seconds, reinstall it and restart the meter. Seek support if the error persists.

What does E1 mean on On Call Plus?

E-1 indicates an internal calibration-check error. Move the meter away from strong radio-frequency or electrical interference and repeat the procedure.

What does E2 mean on On Call Plus?

E-2 means the test strip was removed or lost contact during testing. Repeat with a new strip and keep it fully inserted until the test is complete.

What does E3 mean on On Call Plus?

E-3 means the sample was applied before the meter was ready. Use a new strip and wait for the blood-drop/test-strip symbol before applying blood.

What does E4 mean on On Call Plus?

E-4 indicates a used or contaminated test strip. Discard it and repeat the test with a new compatible On Call Plus strip.

What does E5 mean on On Call Plus?

E-5 indicates an insufficient blood sample. Repeat the test with a fresh strip and ensure enough blood is applied to fill the strip as instructed.

What does E6 mean on On Call Plus?

E-6 means the battery is too low for further glucose testing. Replace the CR2032 battery before repeating the test.

Why does my On Call Plus show CODE?

A CODE warning can occur when the required code chip is not installed. Use the correct code chip associated with the applicable On Call Plus Test Strips.

What does E7 mean?

E-7 is associated with a damaged code chip or a code chip removed during testing. Check the chip and confirm it matches the applicable strip code.

What does E8 mean?

E-8 indicates a meter electronics failure. Persistent E-8 errors require technical support rather than repeated use of additional test strips.

What does E9 mean?

E-9 indicates an incorrect code chip. Confirm that the code chip and test strips are intended for the On Call Plus system.

What does HI mean on an On Call Plus meter?

HI means the glucose result is above the meter's approximately 600 mg/dL upper measurement limit. Repeat the test correctly with a fresh strip and seek prompt medical advice if HI is confirmed.

What does LO mean on an On Call Plus meter?

LO means the result is below the meter's approximately 20 mg/dL lower measurement limit. A repeated LO reading can represent severe low blood glucose and requires appropriate immediate action according to medical guidance.

Why won't my On Call Plus meter recognise the strip?

Check that the strip is compatible, correctly inserted, new, undamaged and within expiry. Also verify battery condition, code-chip setup and the strip port.

Related On Call Plus Guides

Shop On Call Plus at Microsidd

Microsidd supplies On Call Plus meters, kits and compatible test-strip packs for customers across India.

View everything together: On Call Plus Glucometer & Test Strips Collection →

Or explore the entire On Call family: On Call Plus, Extra & GK Dual Collection →

Medical information notice: This troubleshooting guide is intended to explain meter messages and general product operation. It does not diagnose a medical condition, determine whether an individual glucose result is clinically safe, or replace the instructions supplied with the meter or professional medical advice.

If a glucose result is unexpectedly high or low, repeat testing according to the manufacturer's instructions where appropriate. Repeated HI or LO readings, severe symptoms, confusion, loss of consciousness or inability to self-treat require prompt medical assessment. Do not delay appropriate medical care while troubleshooting the meter.

On Call Plus Error Codes & Troubleshooting Guide: E0–E6, HI/LO & Code Chip Errors