P21C1

Cold Start Cylinder 12 Injection Timing

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$17–89 (est.)

Symptoms

Rough engine idling
Difficulty starting in cold weather
Increased fuel consumption
Loss of engine power
Dips during acceleration

Causes

Malfunction of the fuel injector of cylinder 12
Problems with the fuel pump or pressure regulator
Fuel system contamination
Malfunction of sensors (temperature, pressure)
Problems with the engine ECU

How to Fix

Check the condition and operation of the injector of cylinder 12
Diagnose the fuel system (pressure, fuel quality)
Check the condition of the fuel filter
Scan for other errors and sensor readings
If necessary, replace faulty components

Related codes

P21C0 P21C2 P020C