P0419

Code

Generic P — Powertrain

AIR System Control B Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 30 EN: 45 RU: 34

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Read freeze frame and live data with a scan tool; confirm P0419 and any related codes
Perform a visual inspection of AIR pump, solenoids, relays, fuses and connectors for damage or corrosion
Inspect wiring harness routing for chafing, pinched wires, or water entry
Check fuse(s) and relay(s) for the secondary air system
Command the AIR control B output with a scan tool and observe response (voltage, clicking, or pump/valve activation)
Measure voltage/ground at the AIR solenoid connector with key on and while commanding from the PCM

Supply voltage at fuse/relay: ~12 V (key on)
PCM control signal: typically a switched ground or 0–12 V command pulse (depends on vehicle)
Expected AIR solenoid coil resistance (typical range): ~5–50 ohms (manufacturer-specific)
No continuity to ground (open) or very low resistance (short) at the control circuit indicates wiring or solenoid faults
When commanded by PCM, auxiliary relay (if used) should click and pump/valve should show activation in live data

Verify code and any related codes (P0418, P0410, etc.). Note freeze-frame data and conditions when the code set.
Visually inspect connectors, wiring and components for damage, corrosion, or disconnection. Repair obvious issues and retest.
Check relevant fuse(s) and relay(s). Replace blown fuse or faulty relay, then clear codes and retest.
With connector disconnected, measure AIR solenoid coil resistance. If open or shorted outside expected range, replace the solenoid.
Backprobe solenoid connector with key on; verify constant battery voltage to the supply terminal and that the control terminal switches (to ground or to ~12 V) when commanding from a scan tool.
Command the AIR control B circuit on/off with a scan tool while observing voltage and listening/feeling for valve/pump activation. If PCM commands but device does not operate and supply is present, replace solenoid/valve or pump as applicable.
If device works when directly powered but not when controlled by PCM and wiring is good, check continuity between PCM and solenoid and inspect connector pins. Repair wiring or connectors as needed.
If wiring and components test good but code persists, consider PCM driver fault and perform manufacturer-specific PCM tests before replacement.
After repairs, clear codes, perform functional test and, if possible, complete a drive cycle or readiness check to verify the fault does not return.