What Does P1397 Mean?
The engine control module has detected a circuit fault with the secondary (B) camshaft position sensor on Bank 1. This sensor monitors intake or exhaust cam position for variable valve timing control and may have an electrical or signal issue.
Common Causes
35%
Failed camshaft position sensor B with internal electrical fault
25%
Damaged or corroded wiring harness or connector to cam sensor
15%
Worn camshaft reluctor wheel or missing/damaged sensor teeth
15%
Incorrect sensor air gap or loose mounting causing erratic signal
10%
Short or open circuit in sensor wiring or poor ground connection
Diagnostic Steps
1
Step 1: Inspect camshaft position sensor B connector for corrosion, oil contamination, or damaged pins
2
Step 2: Monitor sensor signal pattern using oscilloscope while cranking engine
3
Step 3: Measure sensor resistance and compare to specifications; check voltage supply and ground
4
Step 4: Verify proper sensor installation and air gap according to manufacturer specifications
5
Step 5: Inspect camshaft reluctor wheel for damage and verify cam timing alignment
Estimated Repair Cost
$120 - $500
Parts + labor, varies by vehicle and location
The engine control module has detected a circuit fault with the secondary (B) camshaft position sensor on Bank 1. This sensor monitors intake or exhaust cam position for variable valve timing control and may have an electrical or signal issue.
The most common cause of P1397 (Camshaft Position Sensor "B" Circuit (Bank 1)) is: Failed camshaft position sensor B with internal electrical fault
Typical repair costs for P1397 range from $120 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may run in reduced power mode with VVT disabled. Generally safe to drive but with compromised performance and fuel economy until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1397 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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