What Does P1556 Mean?
The engine control module has detected an open circuit in the camshaft position actuator control circuit for Bank 1 intake camshaft. This indicates a break in the electrical connection preventing the ECM from controlling variable valve timing.
Common Causes
35%
Broken or damaged wiring between ECM and camshaft actuator solenoid
30%
Failed camshaft position actuator solenoid (VVT solenoid)
20%
Corroded or loose electrical connector at actuator
15%
ECM internal circuit failure
Diagnostic Steps
1
Step 1: Visually inspect the camshaft actuator solenoid connector and wiring for damage, corrosion, or disconnection
2
Step 2: Measure resistance of the camshaft actuator solenoid (typically 6-12 ohms); replace if out of specification
3
Step 3: Check for battery voltage at the actuator connector with key on; verify proper ground circuit continuity
4
Step 4: Test continuity between ECM connector and actuator connector to identify any open circuits in wiring harness
5
Step 5: If all wiring and actuator test good, suspect ECM internal driver circuit failure
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The engine control module has detected an open circuit in the camshaft position actuator control circuit for Bank 1 intake camshaft. This indicates a break in the electrical connection preventing the ECM from controlling variable valve timing.
The most common cause of P1556 ("A" Camshaft Position Actuator Control Open Circuit Bank 1) is: Broken or damaged wiring between ECM and camshaft actuator solenoid
Typical repair costs for P1556 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive but performance and fuel economy will be reduced. Extended driving may cause increased emissions and potential engine wear.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1556 to identify the root cause.
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Quick Info
Category
Powertrain
System
Variable Valve Timing System
Difficulty
Type
Manufacturer
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