P1421moderate severityPowertrain
Cold Start Control
on 2012 Nissan Pathfinder 4.0L V6 VQ40DE · RWD
What this code means
The ECM detected a fault in the cold start emission control system used to warm the catalyst quickly. This affects emissions during warm-up rather than normal driving.
Symptoms
- Check engine light on
- Rough cold idle
- Increased emissions on startup
Common causes
- Faulty A/F or O2 sensor
- Ignition timing control fault
- Intake air temp sensor issue
- ECM fault
Diagnostic steps
- Retrieve freeze frame data
- Check A/F and O2 sensor operation
- Verify ignition timing control
- Inspect intake air temp sensor
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Budget handheld~$40
ANCEL AD410 →
No-phone-needed handheld — reads, clears, live data, freeze frame.
✓ ANCEL official store
Serious DIY~$100
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
SHOP FAVORITEShop-grade tablet~$300
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
✓ Autel official store
Pro diagnostics$1,500+
Autel MaxiSys MS906 Pro →
Full-system pro platform — topology mapping, ECU coding, the works.
✓ Autel official store
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0005
Fuel Shutoff Valve A Control Circuit/Open
P0006
Fuel Shutoff Valve A Control Circuit Low
P0007
Fuel Shutoff Valve A Control Circuit High
P0008
Engine Position System Performance - Bank 1
P0009
Engine Position System Performance - Bank 2
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1