OBD2 Car ScannerWhat does P3400 mean?
P3400 stands for Cylinder Deactivation System Bank 1. This is a manufacturer-specific code: its exact meaning can differ between car brands. The description below is the most common one.
Powertrain codes cover the engine, transmission and emissions. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.
Common causes
- Look up the code for your exact make and model
- Check for related generic (P0) codes
- Ask a dealer or specialist if unsure
What to do
- Read all stored and pending codes with a scanner. Several codes together often point to one cause.
- Note the freeze frame data (speed, temperature, load) recorded when the code was set.
- Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
- Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.
Read this code from your own car
Plug in a cheap ELM327 adapter and the app shows every fault code, what it means and how to fix it.
Frequently asked questions
What does P3400 mean?
P3400 means “Cylinder Deactivation System Bank 1”. It belongs to the manufacturer-specific code group: This is a manufacturer-specific code: its exact meaning can differ between car brands. The description below is the most common one.
Is it safe to drive with P3400?
You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.
How do I clear P3400?
Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.
Related codes
- P2A03O2 Sensor Circuit Range/Performance Bank 2 Sensor 1
- P2A04O2 Sensor Circuit Range/Performance Bank 2 Sensor 2
- P2A05O2 Sensor Circuit Range/Performance Bank 2 Sensor 3
- P2BACNOx Exceedence - Deactivation of EGR
- P3401Cylinder 1 Deactivation/Intake Valve Control Circuit/Open
- P3402Cylinder 1 Deactivation/Intake Valve Control Circuit Performance
- P3403Cylinder 1 Deactivation/Intake Valve Control Circuit Low
- P3404Cylinder 1 Deactivation/Intake Valve Control Circuit High
Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.