P0843 — Transmission Fluid Pressure Sensor/Switch A Circuit High

What Does P0843 Mean?

P0843 is a diagnostic trouble code indicating: Transmission Fluid Pressure Sensor/Switch A Circuit High. This code relates to the transmission system. It has been reported in NHTSA complaints across 2 different vehicle models.

Symptoms of P0843

⚠️ Engine misfires
⚠️ Oil leak or excessive consumption

Common Causes

🔍 Worn or fouled spark plugs

P0843 Reports by Year

2019

1

2025

1

Real Owner Reports

From NHTSA complaint database — actual owner descriptions.

"The contact owns a 2013 Honda Odyssey. The contact stated that while driving at an undisclosed speed, the vehicle made an abnormal rattling sound occasionally. The check engine warning light was illuminated. The vehicle was taken to a local dealer, where it was diagnosed with a cylinder 3 misfire, D"
— Honda Odyssey owner, 01/15/2019

"CVT Transmission Failure. Failure occurred at approximately 66,706 miles on 5/16/25. The Check Engine and AT Temp lights appeared in the instrument cluster. The driving conditions when this happened were a safety concern. First, the vehicle would crawl, shutter, and almost stall with high RPMs w"
— Subaru Legacy owner, 05/16/2025

Source: NHTSA Complaints Database

Most Reported Vehicles for P0843

Based on NHTSA owner complaint data.

#	Vehicle	Reports
1	HONDA ODYSSEY
2	SUBARU LEGACY

Frequently Asked Questions

Is it safe to drive with this transmission code?

Use caution. Transmission codes can indicate serious issues that worsen with continued driving. Avoid highway speeds until diagnosed.

Do I need a full transmission rebuild?

Not necessarily. Many transmission codes are caused by solenoids, sensors, or low fluid — which are much cheaper fixes than a rebuild.

How much does a transmission repair cost?

Solenoid replacement: $200-500. Valve body: $500-1,000. Full rebuild: $1,800-3,500. Get a proper diagnosis first.

What To Do Next

Possible Fixes

🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
🔧 Check transmission fluid level and condition; top off or change if needed
🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P0843: Transmission Fluid Pressure Sensor/Switch A Circuit High