P21B7

Cold Start Cylinder 2 Injection Timing

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$17–89 (est.)

Symptoms

Unstable engine operation at idle
Increased fuel consumption
Difficult cold start
Loss of engine power
Increased emissions of harmful substances

Causes

Malfunction of the fuel injector of cylinder 2
Problems with the fuel pump or pressure regulator
Malfunction of sensors (mass air flow sensor, coolant temperature sensor)
Problems with the engine ECU
Fuel system contamination

How to Fix

Check the condition of the fuel injector of cylinder 2
Check the pressure in the fuel system
Diagnose the operation of sensors (mass air flow sensor, coolant temperature)
Check the wiring harness to the injector
Clean the fuel system if necessary

Related codes

P21B6 P21B8 P21B9