C1247: Brake pedal stroke sensor fault (Toyota)

Brake pedal stroke (delta S) sensor malfunction

Severity: Inspect soon

Toyota's owner's manual says an ABS warning light means a fault in the ABS or brake assist system and the vehicle should be inspected by a dealer immediately. Normal braking remains, but anti-lock and stability help may be off.

It gets more serious if:

Stop: The red BRAKE warning light stays on together with the ABS light. Toyota says to stop in a safe place, because braking can become unstable.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

C1247 in short

On Toyotas, C1247 means the skid control computer found a fault with the brake pedal stroke sensor signal. The ABS and VSC lights come on and the check engine light may too. Toyota has software bulletins for some Sequoia, Prius and Camry Hybrid years, so have a dealer check soon.

The brake pedal stroke sensor, which Toyota also calls the delta S sensor, reports how far and how fast the brake pedal moves. The skid control ECU uses it for brake assist and stability control. If the signal sits stuck near the top or bottom of its range, the ECU stores C1247 and turns on the warning lights.

Toyota issued bulletins that address this code by changing the ECU's detection logic: one for the 2003–2005 Sequoia, where it pairs with C1310, one for the 2004–2009 Prius and one for the 2007–2011 Camry Hybrid. On those vehicles a software update may be the fix rather than a new part.

On the Sequoia, the sensor is part of the brake booster assembly, so Toyota's repair manual lists the booster, the sensor, its wiring and the skid control ECU as the possible trouble areas.

Pick your make

C1247 is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

C1247 on Toyota

Most likely causes

Cause 1: Skid control ECU detection logic needing an update
Supported by vehicle data
Why it ranks here
Toyota bulletins for the 2003–2005 Sequoia, 2004–2009 Prius and 2007–2011 Camry Hybrid address C1247 with a change to the ECU's logic. These bulletins are not verified as current.
What would change this
Rises on a vehicle covered by one of these bulletins that has not had the update. Falls if the update is already done.
Cause 2: Failed brake pedal stroke (delta S) sensor or brake booster
Possible — needs testing
Why it ranks here
Toyota's repair manual lists the delta S sensor and the brake booster it is part of as trouble areas when the signal is out of range.
What would change this
Rises if the sensor reading is stuck at one end of its range with the pedal moving. Falls if the reading tracks the pedal smoothly.
Cause 3: Fault in the stroke sensor wiring or connector
Possible — needs testing
Why it ranks here
The repair manual lists the sensor circuit as a trouble area.
What would change this
Rises if wiggling the harness changes the reading. Falls if the circuit checks good.
Cause 4: Faulty skid control ECU
Possible — needs testing
Why it ranks here
The repair manual lists the skid control ECU as a trouble area, and Sequoia owners report dealers replacing it for this code.
What would change this
Rises only after the sensor, wiring and any software update have been ruled out.
How to test the brake system control module (abs module)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Have the ABS/VSC codes read with a scan tool and note any other codes stored with C1247.
Low riskTool: scan tool with ABS/VSC access
- IfC1247 with C1310 on a 2003–2005 Sequoia
  It meansToyota bulletin 00606 covers this pair.
  Go to step 2 Points to: Skid control ECU detection logic needing an update
- IfC1247 on a 2004–2009 Prius or 2007–2011 Camry Hybrid
  It meansA Toyota bulletin covers the stroke sensor detection logic.
  Go to step 2 Points to: Skid control ECU detection logic needing an update
- IfAny other vehicle
  It meansThe service manual diagnosis is next.
  Go to step 3
Step 2: Give your VIN to a Toyota dealer and ask whether a skid control ECU update for C1247 applies and has been done.
Low risk
- IfThe update applies and has not been done
  It meansThe dealer applies it and rechecks.
  Points to: Skid control ECU detection logic needing an update
- IfNo update applies, or it is done and the code returns
  It meansThe sensor and wiring need testing.
  Go to step 3
Step 3: Have a technician watch the stroke sensor reading while pressing the pedal and test its wiring as the service manual directs.
Best left to a shopTool: Toyota diagnostic tool and service information
Warning:This is brake system work on a power brake booster. Leave it to a qualified technician, and do not drive if the red BRAKE light is on with the ABS light.
- IfThe reading is stuck high or low while the pedal moves
  It meansThe sensor or booster is suspect.
  Points to: Failed brake pedal stroke (delta S) sensor or brake booster
- IfThe reading drops out when the harness is moved
  It meansThe wiring or connector is at fault.
  Points to: Fault in the stroke sensor wiring or connector
- IfSensor and wiring are good
  It meansThe skid control ECU is suspect.
  Points to: Faulty skid control ECU

Symptoms

ABS, VSC and slip lights on
Check engine light on with the ABS lights
Red BRAKE light on along with the ABS light Gets more serious: stop and have it checked.

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

Skid control ECU, stroke sensor or brake booster:On vehicles covered by a Toyota bulletin, a software update may come before any part. Sequoia owners report dealers replacing the ECU, actuator or booster. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Toyota

2003–2005 · Sequoia
Supported by vehicle data
Toyota bulletin 00606 changes the skid control computer logic for C1247 with C1310. Owners also report C1223 stored with it. Whether the bulletin is still current is not verified.
2004–2009 · Prius
Supported by vehicle data
A Toyota bulletin addresses C1247 with a change to the stroke sensor detection logic. Whether it is still current is not verified.
2007–2011 · Camry
Supported by vehicle data
Camry Hybrid only: a Toyota bulletin addresses C1247 the same way as on the Prius. Whether it is still current is not verified.

00606Status unverified
Check engine light on with C1247 and C1310: skid control computer logic change
2003–2005sequoia · issued March 31, 2006 · NHTSA 10019688
Changes the skid control computer's logic for this pair of codes.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
T-SB-0174-12 RevStatus unverified
Check engine and ABS/VSC lights with C1247 (stroke sensor malfunction)
2004–2009prius · issued June 25, 2014 · NHTSA 10132768
Addresses the stroke sensor detection logic in the ABS/VSC ECU.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
T-SB-0040-14Status unverified
Camry Hybrid: check engine and ABS/VSC lights with C1247 (stroke sensor malfunction)
2007–2011camry · issued June 25, 2014 · NHTSA 10132767
Same issue as the Prius bulletin, for the Camry Hybrid only.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

All ABS, traction and stability control codes

C1247 questions

Is C1247 always a bad sensor?

No. On some Sequoia, Prius and Camry Hybrid years Toyota addressed it with a change to the ECU's detection logic, so ask a dealer about the bulletin before replacing parts.

Sources and review

Camry Owner's Manual (OM06291U) — Toyota
Toyota 00606: MIL on with DTC C1247 and C1310, skid control computer logic change — Toyota / NHTSA , March 31, 2006
Toyota T-SB-0174-12 Rev: MIL and ABS/VSC lights with DTC C1247 (stroke sensor malfunction) — Toyota / NHTSA , June 25, 2014
Toyota T-SB-0040-14: MIL and ABS/VSC lights with DTC C1247 (stroke sensor malfunction) — Toyota / NHTSA , June 25, 2014
2005 Toyota Sequoia repair manual: DTC C1247/47 delta S sensor malfunction — Toyota Motor Corporation (third-party mirror)
2005 Toyota Sequoia repair manual: ABS/VSC diagnostic trouble code chart — Toyota Motor Corporation (third-party mirror)
Owner complaints: 2003-2005 Toyota Sequoia ABS, VSC and brake lights with C1223 and C1247 — NHTSA Office of Defects Investigation
2005 Toyota Sequoia repair manual: DTC C1223/43 malfunction in ABS control system — Toyota Motor Corporation (third-party mirror)

Last reviewed: October 15, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Pick your make

Most likely causes

Cause 1: Skid control ECU detection logic needing an update

Cause 2: Failed brake pedal stroke (delta S) sensor or brake booster

Cause 3: Fault in the stroke sensor wiring or connector

Cause 4: Faulty skid control ECU

What to test first

Step 1: Have the ABS/VSC codes read with a scan tool and note any other codes stored with C1247.

Step 2: Give your VIN to a Toyota dealer and ask whether a skid control ECU update for C1247 applies and has been done.

Step 3: Have a technician watch the stroke sensor reading while pressing the pedal and test its wiring as the service manual directs.