🌿String Trimmer

E01

STIHL · FS 91 R Trimmer

STIHL FS 91 R Trimmer E01 Error Fix: Engine Overheating

This error indicates the engine temperature has exceeded safe operating limits, typically triggered by prolonged use or inadequate cooling. The trimmer may shut down automatically to prevent damage.

High severity2 fixes available

Quick Answer

Error E01 on the STIHL FS 91 R Trimmer means: Engine Overheating. The top-ranked community fix is “Clean Cooling Fins and Air Intake” (easy difficulty, ~20 min, DIY cost: $0-$5). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · string trimmer

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

Root Cause Analysis

Sensor MalfunctionPrimary

When to Call a Professional

While many string trimmer repairs can be done safely at home, consider hiring a qualified technician if:

This is a high severity error — continued use may cause damage or a safety hazard
The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $70-$120.

Other STIHL Models with Error E01

BG 86 C-E Blower

leaf_blower · 2 fixes

BGA 57 Battery Blower

leaf_blower · 2 fixes

FS 56 RC-E Trimmer

string_trimmer · 2 fixes

FSA 57 Battery Trimmer

string_trimmer · 2 fixes

MS 180 C-BE Chainsaw

chainsaw · 2 fixes

MS 250 45.4 cc 2-Stroke Gas Chainsaw with 18" Bar and Anti-Vibration System

chainsaw · 2 fixes

MS 362 C-M Chainsaw

chainsaw · 2 fixes

MSA 220 C-B Battery

chainsaw · 2 fixes

Other STIHL FS 91 R Trimmer Error Codes

DIES AT IDLE

Engine Dies When Idling

1 fix

E02

Fuel Mixture Imbalance

2 fixes

E03

Ignition Coil Failure

Clutch Slippage

Throttle Trigger Malfunction

Air Filter Clogging

Spark Plug Fouling

Fuel Line Crack or Leak

2 fixes

People Also Ask About STIHL FS 91 R Trimmer Error E01

What does error code E01 mean on a STIHL FS 91 R Trimmer?

Error code E01 on the STIHL FS 91 R Trimmer means: Engine Overheating. This error indicates the engine temperature has exceeded safe operating limits, typically triggered by prolonged use or inadequate cooling. The trimmer may shut down automatically to prevent damage.

How do I fix error code E01 on my STIHL FS 91 R Trimmer?

The most successful fix is "Clean Cooling Fins and Air Intake" (easy difficulty, ~20 minutes). Estimated DIY cost: $0-$5. HomeMD has 2 community-ranked fixes for this error.

Is error code E01 on a STIHL FS 91 R Trimmer serious?

This error is rated high severity. You should address it promptly — continued use could cause damage or safety concerns.

Can I fix STIHL FS 91 R Trimmer error E01 myself?

Yes — the top-ranked community fix ("Clean Cooling Fins and Air Intake") is rated easy difficulty and takes about 20 minutes. Tools needed: Soft brush, Compressed air can.

How much does it cost to repair STIHL FS 91 R Trimmer error E01?

DIY cost: $0-$5. Professional repair typically costs $70-$120. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the STIHL FS 91 R Trimmer have?

The STIHL FS 91 R Trimmer has 8 other known error codes, including: DIES AT IDLE (Engine Dies When Idling), E02 (Fuel Mixture Imbalance), E03 (Ignition Coil Failure), E04 (Clutch Slippage), E05 (Throttle Trigger Malfunction), and 3 more.

Which other STIHL models have the E01 error?

Error code E01 also appears on 8 other STIHL models: BG 86 C-E Blower, BGA 57 Battery Blower, FS 56 RC-E Trimmer, FSA 57 Battery Trimmer, MS 180 C-BE Chainsaw, MS 250 45.4 cc 2-Stroke Gas Chainsaw with 18" Bar and Anti-Vibration System, and 2 more. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the STIHL FS 91 R Trimmer have?

The STIHL FS 91 R Trimmer has 8 other known error codes:

DIES AT IDLE — Engine Dies When Idling (1 fix)
E02 — Fuel Mixture Imbalance (2 fixes)
E03 — Ignition Coil Failure (2 fixes)
E04 — Clutch Slippage (2 fixes)
E05 — Throttle Trigger Malfunction (2 fixes)
E06 — Air Filter Clogging (2 fixes)
E07 — Spark Plug Fouling (2 fixes)
E08 — Fuel Line Crack or Leak (2 fixes)

Which other STIHL models have the E01 error?

Error code E01 also appears on 8 other STIHL models:

BG 86 C-E Blower (leaf blower) · 2 fixes
BGA 57 Battery Blower (leaf blower) · 2 fixes
FS 56 RC-E Trimmer (string trimmer) · 2 fixes
FSA 57 Battery Trimmer (string trimmer) · 2 fixes
MS 180 C-BE Chainsaw (chainsaw) · 2 fixes
MS 250 45.4 cc 2-Stroke Gas Chainsaw with 18" Bar and Anti-Vibration System (chainsaw) · 2 fixes
MS 362 C-M Chainsaw (chainsaw) · 2 fixes
MSA 220 C-B Battery (chainsaw) · 2 fixes

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