What Does P1154 Mean?
This code indicates a malfunction in the air assist control valve circuit. The air assist (or secondary air injection assist) valve is responsible for directing supplemental air into the exhaust stream during cold starts to accelerate catalytic converter warm-up. A circuit malfunction means the PCM detected an open, short, or out-of-range signal in the valve's control circuit, preventing proper secondary air operation.
Common Causes
30%
Failed air assist control valve (solenoid stuck open or closed)
25%
Open or shorted wiring in the air assist valve control circuit
20%
Corroded or disconnected connector at the air assist valve
15%
Blown fuse or relay for the secondary air injection system
10%
PCM driver circuit failure for the air assist valve
Diagnostic Steps
1
Check the fuse and relay for the secondary air injection system; replace if blown.
2
Unplug the air assist control valve connector and measure resistance across the solenoid coil; compare to manufacturer specifications (typically 20-40 ohms).
3
Test for battery voltage and proper ground at the valve connector with the key on and valve commanded active.
4
Inspect the wiring harness between the PCM and the air assist valve for breaks, shorts to ground, or shorts to power.
5
If electrical tests pass, replace the air assist control valve and clear codes to verify repair.
Estimated Repair Cost
$100 - $350
Parts + labor, varies by vehicle and location
This code indicates a malfunction in the air assist control valve circuit. The air assist (or secondary air injection assist) valve is responsible for directing supplemental air into the exhaust stream during cold starts to accelerate catalytic converter warm-up. A circuit malfunction means the PCM ...
The most common cause of P1154 (Air Assist Control Valve Circuit Malfunction) is: Failed air assist control valve (solenoid stuck open or closed)
Typical repair costs for P1154 range from $100 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No direct safety risk. The vehicle remains drivable but may fail emissions testing due to increased cold-start hydrocarbon emissions and delayed catalytic converter light-off.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1154 to identify the root cause.
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Quick Info
Category
Powertrain
System
Secondary Air Injection
Difficulty
Type
Manufacturer
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