What Does P1285 Mean?
The PCM has detected an abnormally high voltage signal from the air-assisted injection valve solenoid control circuit on bank 1. This indicates the control circuit voltage is above expected parameters.
Common Causes
35%
Open circuit in solenoid control wiring
30%
Failed air injection switching solenoid with internal open
20%
Poor ground connection at solenoid
15%
Corroded or disconnected connector terminals
Diagnostic Steps
1
Step 1: Visually inspect solenoid connector for loose, corroded, or backed-out pins
2
Step 2: Check solenoid coil resistance with connector disconnected
3
Step 3: Test for continuity in control circuit from PCM to solenoid connector
4
Step 4: Verify ground circuit continuity and quality
5
Step 5: Monitor voltage at solenoid connector with ignition on, engine off to check for proper supply
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The PCM has detected an abnormally high voltage signal from the air-assisted injection valve solenoid control circuit on bank 1. This indicates the control circuit voltage is above expected parameters.
The most common cause of P1285 (Switching Solenoid for Air Assisted Injection Valves Bank 1 Control Circuit Signal High) is: Open circuit in solenoid control wiring
Typical repair costs for P1285 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle remains safe to drive but may have reduced performance, increased emissions, and rough running. Repair within a few days.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1285 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection / Air-Assist System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
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